Search

Your search keyword '"William J. Jenkins"' showing total 159 results
Start Over Author "William J. Jenkins"
159 results on '"William J. Jenkins"'

1. Evidence of an active volcanic heat source beneath the Pine Island Glacier

Author

Brice Loose, Alberto C. Naveira Garabato, Peter Schlosser, William J. Jenkins, David Vaughan, and Karen J. Heywood

Subjects
Science
Abstract

The West Antarctic Ice Sheet sits atop an extensional rift system with volcano-like features, yet we do not know if any of these volcanoes are active, because identifying subglacial volcanism remains a challenge. Here, the authors find evidence in helium isotopes that a large volcanic heat source is emanating from beneath the fast-melting Pine Island Ice Glacier.

Published
2018
Full Text
View/download PDF

2. Psychology 2e

Author

Rose M. Spielman, William J. Jenkins, Marilyn D. Lovett and Rose M. Spielman, William J. Jenkins, Marilyn D. Lovett

Published
2020

4. Major processes of the dissolved cobalt cycle in the North and equatorial Pacific Ocean

Author

Rebecca Chmiel, Matthew R. McIlvin, Phoebe J. Lam, Mariko Hatta, Mak A. Saito, Alessandro Tagliabue, William J. Jenkins, Jessica N. Fitzsimmons, Allison Laubach, Nathan T. Lanning, and Jong-Mi Lee

Subjects
Biogeochemical cycle, geography, geography.geographical_feature_category, Mesopelagic zone, Geotraces, Seamount, Oceanography, Phytoplankton, Environmental science, Thermohaline circulation, Transect, Scavenging, Ecology, Evolution, Behavior and Systematics, Earth-Surface Processes
Abstract

Over the past decade, the GEOTRACES and wider trace metal geochemical community have made substantial contributions towards constraining the marine cobalt (Co) cycle and its major biogeochemical processes. However, few Co speciation studies have been conducted in the North and equatorial Pacific Ocean, a vast portion of the world’s oceans by volume and an important endmember of deep thermohaline circulation. Dissolved Co (dCo) samples, including total dissolved and labile Co, were measured at-sea during the GEOTRACES Pacific meridional transect (GP15) along the 152° W longitudinal from 56° N to 20° S. Along this transect, upper ocean dCo was linearly correlated to dissolved phosphate (slope = 82 ± 2 µM:M) due to phytoplankton uptake and remineralization. As depth increased, dCo concentrations became increasingly decoupled from phosphate concentrations due to co-scavenging with manganese oxide particles in the mesopelagic. The transect revealed an organically-bound coastal source of dCo to the Alaskan Stream associated with low salinity waters. An intermediate-depth hydrothermal flux of dCo was observed off the Hawaiian coast at the Loihi Seamount, and the elevated dCo was correlated to estimated xs3He at and above the vent site; however, the Loihi Seamount likely did not represent a major source of Co to the Pacific basin. Elevated concentrations of dCo within oxygen minimum zones (OMZs) in the equatorial North and South Pacific were consistent with the suppression of oxidative scavenging, and we estimate that future deoxygenation could increase the OMZ dCo inventory by 13–28 % over the next century. In North Pacific Deep Water (NPDW), a fraction of elevated ligand-bound dCo appeared protected from scavenging by the high biogenic particle flux in the North Pacific basin. This finding is counter to previous expectations of low dCo concentrations in the deep Pacific due to scavenging over thermohaline circulation. Compared to a Co global biogeochemical model, the observed transect displayed more extreme inventories and fluxes of dCo than predicted by the model, suggesting a highly dynamic Pacific Co cycle.

Published
2021

5. 14C Blank Corrections for 25–100 μg Samples at the National Ocean Sciences AMS Laboratory

Author

William J. Jenkins, Alan R. Gagnon, Mark L. Roberts, Li Xu, Brett E. Longworth, Joshua D. Hlavenka, and Kathryn L. Elder

Subjects
Archeology, Accuracy and precision, chemistry, Sample processing, Analytical chemistry, General Earth and Planetary Sciences, chemistry.chemical_element, Environmental science, Replicate, Carbon, Blank
Abstract

Replicate radiocarbon (14C) measurements of organic and inorganic control samples, with known Fraction Modern values in the range Fm = 0–1.5 and mass range 6 μg–2 mg carbon, are used to determine both the mass and radiocarbon content of the blank carbon introduced during sample processing and measurement in our laboratory. These data are used to model, separately for organic and inorganic samples, the blank contribution and subsequently “blank correct” measured unknowns in the mass range 25–100 μg. Data, formulas, and an assessment of the precision and accuracy of the blank correction are presented.

Published
2019

6. A determination of atmospheric helium, neon, argon, krypton, and xenon solubility concentrations in water and seawater

Author

K.L. Cahill, William J. Jenkins, and Dempsey E. Lott

Subjects
0106 biological sciences, Argon, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Krypton, Analytical chemistry, Temperature salinity diagrams, Noble gas, chemistry.chemical_element, General Chemistry, Oceanography, 01 natural sciences, Freezing point, Neon, Xenon, chemistry, Environmental Chemistry, Environmental science, Seawater, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Water Science and Technology
Abstract

We have determined the concentrations of atmospheric helium, neon, argon, krypton , and xenon in distilled water and seawater equilibrated with moist marine air at one atmosphere over a temperature range from near freezing point to approximately 35 °C and a salinity range of zero to roughly 39.5 PSS78. In all, we made 74 sets of noble gas measurements at 34 distinct temperature and salinity combinations. The experiments included 35 replicate pairs of samples drawn from 35 separate equilibrations, which in turn had three pairs of repeat equilibrations run at close to identical temperatures. We fit the results to an eight-parameter function similar to one commonly used to compute solubility equilibrium concentrations of these gases for environmental waters. Based on an estimate of analytical accuracy, reproducibility of the comparison with secondary atmospheric standards, replicate sample reproducibility, and reproducibility of the repeat equilibrations, we estimate this function to predict equilibrium concentrations at a particular temperature and salinity within this range to overall precisions 0.10% or better. This includes the regression statistics associated with interpolation and analytical errors for fitting the 8-parameter smoothing function. There is an overall systematic uncertainty of 0.15% for all gases, based on our confidence in and experience with the integrity and cross-calibration of our air standards over recent years. Because our methods are calibrated using assumed and explicit atmospheric abundances of these noble gases, any subsequent uncertainties in atmospheric abundances cancel out in the determination, particularly when the oceanographic measurements utilize marine air as a primary standard. Furthermore, measurement at ambient atmospheric abundances avoids any potential co-solvency induced biases introduced by using ~1 atm pure noble gases, as has been done in most previous studies. We compare these determinations to those made by others in the past and find modest but significant systematic differences with those results.

Published
2019

7. Using Noble Gases to Assess the Ocean's Carbon Pumps

Author

Steven Emerson, Roberta C. Hamme, David P. Nicholson, and William J. Jenkins

Subjects
0106 biological sciences, Solubility pump, Carbon dioxide in Earth's atmosphere, Argon, 010504 meteorology & atmospheric sciences, Arctic Regions, Oceans and Seas, 010604 marine biology & hydrobiology, Krypton, Biological pump, chemistry.chemical_element, Carbon Dioxide, Oceanography, Atmospheric sciences, Noble Gases, 01 natural sciences, Neon, chemistry, Environmental science, Seawater, Oceanic carbon cycle, Carbon, 0105 earth and related environmental sciences
Abstract

Natural mechanisms in the ocean, both physical and biological, concentrate carbon in the deep ocean, resulting in lower atmospheric carbon dioxide. The signals of these carbon pumps overlap to create the observed carbon distribution in the ocean, making the individual impact of each pump difficult to disentangle. Noble gases have the potential to directly quantify the physical carbon solubility pump and to indirectly improve estimates of the biological organic carbon pump. Noble gases are biologically inert, can be precisely measured, and span a range of physical properties. We present dissolved neon, argon, and krypton data spanning the Atlantic, Southern, Pacific, and Arctic Oceans. Comparisons between deep-ocean observations and models of varying complexity enable the rates of processes that control the carbon solubility pump to be quantified and thus provide an important metric for ocean model skill. Noble gases also provide a powerful means of assessing air–sea gas exchange parameterizations.

Published
2019

8. Using Excess 3 He to Estimate Southern Ocean Upwelling Time Scales

Author

William J. Jenkins

Subjects
chemistry.chemical_element, Atmospheric sciences, Hydrothermal circulation, Neon, Geophysics, chemistry, Dissolved iron, General Earth and Planetary Sciences, Environmental science, Upwelling, Thermohaline circulation, Marine productivity, Isotopes of helium, Helium
Abstract

Using a recently compiled global marine dataset of dissolved helium isotopes and helium and neon concentrations, we make an estimate of the inventory of hydrothermal He in the Southern Ocean to be ...

Published
2020

10. An intermediate-depth source of hydrothermal 3He and dissolved iron in the North Pacific

Author

Jessica N. Fitzsimmons, Chris German, Reiner Schlitzer, Mariko Hatta, Laura M. Whitmore, Dempsey E. Lott, G. Weiss, William J. Jenkins, N.R. Buckley, Alan E. Shiller, K.L. Cahill, Phoebe J. Lam, Nathan T. Lanning, Karen L. Casciotti, and Gregory A. Cutter

Subjects
geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Seamount, Geochemistry, Flux, 010502 geochemistry & geophysics, 01 natural sciences, Hydrothermal circulation, Plume, Abyssal zone, Geophysics, Water column, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Trace metal, 14. Life underwater, Primitive mantle, Geology, 0105 earth and related environmental sciences
Abstract

We observed large water column anomalies in helium isotopes and trace metal concentrations above the Loihi Seamount. The 3He/4He of the added helium was 27.3 times the atmospheric ratio, clearly marking its origin to a primitive mantle plume. The dissolved iron to 3He ratio (dFe:3He) exported to surrounding waters was 9.3 ± 0.3 × 10 6 . We observed the Loihi 3He and dFe “signal” at a depth of 1100 m at several stations within ∼100 – 1000 km of Loihi, which exhibited a distal dFe:3He ratio of ∼ 4 × 10 6 , about half the proximal ratio. These ratios were remarkably similar to those observed over and near the Southern East Pacific Rise (SEPR) despite greatly contrasting geochemical and volcanic-tectonic origins. In contrast, the proximal and distal dMn:3He ratios were both ∼ 1 × 10 6 , less than half of that observed at the SEPR. Dissolved methane was minimally enriched in waters above Loihi Seamount and was distally absent. Using an idealized regional-scale model we replicated the historically observed regional 3He distribution, requiring a hydrothermal 3He source from Loihi of 10.4 ± 4.2 mol a−1, ∼2% of the global abyssal hydrothermal 3He flux. From this we compute a corresponding dFe flux of ∼40 Mmol a−1. Global circulation model simulations suggest that the Loihi-influenced waters eventually upwell along the west coast of North America, also extending into the shallow northwest Pacific, making it a possibly important determinant of marine primary production in the subpolar North Pacific.

Published
2020

11. Evidence of an active volcanic heat source beneath the Pine Island Glacier

Author

David G. Vaughan, Peter Schlosser, Karen J. Heywood, Brice Loose, William J. Jenkins, and Alberto C. Naveira Garabato

Subjects
010504 meteorology & atmospheric sciences, Science, Geochemistry, General Physics and Astronomy, Antarctic ice sheet, Volcanism, 010502 geochemistry & geophysics, 01 natural sciences, General Biochemistry, Genetics and Molecular Biology, Ice shelf, Article, Glacial period, lcsh:Science, Meltwater, 0105 earth and related environmental sciences, geography, Multidisciplinary, Rift, geography.geographical_feature_category, Glacier, General Chemistry, Volcano, 13. Climate action, lcsh:Q, Geology
Abstract

Tectonic landforms reveal that the West Antarctic Ice Sheet (WAIS) lies atop a major volcanic rift system. However, identifying subglacial volcanism is challenging. Here we show geochemical evidence of a volcanic heat source upstream of the fast-melting Pine Island Ice Shelf, documented by seawater helium isotope ratios at the front of the Ice Shelf cavity. The localization of mantle helium to glacial meltwater reveals that volcanic heat induces melt beneath the grounded glacier and feeds the subglacial hydrological network crossing the grounding line. The observed transport of mantle helium out of the Ice Shelf cavity indicates that volcanic heat is supplied to the grounded glacier at a rate of ~ 2500 ± 1700 MW, which is ca. half as large as the active Grimsvötn volcano on Iceland. Our finding of a substantial volcanic heat source beneath a major WAIS glacier highlights the need to understand subglacial volcanism, its hydrologic interaction with the marine margins, and its potential role in the future stability of the WAIS., The West Antarctic Ice Sheet sits atop an extensional rift system with volcano-like features, yet we do not know if any of these volcanoes are active, because identifying subglacial volcanism remains a challenge. Here, the authors find evidence in helium isotopes that a large volcanic heat source is emanating from beneath the fast-melting Pine Island Ice Glacier.

Published
2018

12. Export of Strongly Diluted Greenland Meltwater From a Major Glacial Fjord

Author

William J. Jenkins, Nicholas Beaird, and Fiammetta Straneo

Subjects
geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Fjord, Noble gas (data page), 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, Oceanography, General Earth and Planetary Sciences, Glacial period, Meltwater, Geology, 0105 earth and related environmental sciences
Published
2018

13. The deep distributions of helium isotopes, radiocarbon, and noble gases along the U.S. GEOTRACES East Pacific Zonal Transect (GP16)

Author

Christopher R. German, K.L. Cahill, Dempsey E. Lott, Brett E. Longworth, Joanne Goudreau, and William J. Jenkins

Subjects
Basalt, Water mass, Radiogenic nuclide, 010504 meteorology & atmospheric sciences, Geotraces, chemistry.chemical_element, Flux, Mineralogy, General Chemistry, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Plume, chemistry, Environmental Chemistry, Upwelling, Helium, Geology, 0105 earth and related environmental sciences, Water Science and Technology
Abstract

We report the deep distributions of noble gases, helium isotopes, and radiocarbon measured during the U.S. GEOTRACES GP16 East Pacific Zonal Transect between 152 and 77°W at 12–15°S in the South Pacific. The dominant feature is an intense tongue of hydrothermal effluent that extends > 4000 km westward from the East Pacific Rise (EPR) at ~ 2500 m depth. The patterns reveal significant “downstream” variations in water mass structure, advection, and mixing that belie the simple perception of a continuous plume extending westward from the EPR. For example, one feature observed at 120°W, 14°S has tracer signatures that are consistent with a water mass originating from an area as much as 2000 km south of this section, suggesting a quasi-permanent northward flow on the western flank of the EPR. Helium isotope variations in the plume show a uniquely high 3 He/ 4 He source in the tongue compared with typical mid-ocean ridge basalts (MORB), consistent with the anomalously high ratios observed in MORB glasses from the EPR segment just south of this transect. The water column data also reveal that the background 3 He/ 4 He east of the EPR is significantly lower than values characteristic of MORB, suggesting an additional, more geographically distributed radiogenic 4 He flux of order 10 7 mol/y into the deep Pacific. In the western end of the section, incoming bottom waters have relatively less hydrothermal hydrothermal helium, more radiocarbon, and more oxygen, as well as negative saturation anomalies for the heavy noble gases (Ar, Kr, and Xe). During the basin-scale upwelling of this water, diapycnal mixing serves to erase these negative anomalies. The relative magnitudes of the increases for the heavy noble gases (Ar, Kr, and Xe) are quantitatively consistent with this process. This leads us to estimate the relatively smaller effects on He and Ne saturations, which range from near zero to 0.2% and 0.3% respectively. With this information, we are able to refine our estimates of the magnitude of 3 He and 4 He excesses and the absolute 3 He/ 4 He ratio of non-atmospheric helium introduced into deep Pacific waters.

Published
2018

14. Water mass analysis of the 2013 US GEOTRACES eastern Pacific zonal transect (GP16)

Author

James H. Swift, Gregory A. Cutter, Brian Peters, Christopher R. German, Mark A. Brzezinski, James W. Moffett, Karen L. Casciotti, and William J. Jenkins

Subjects
Water mass, Antarctic Intermediate Water, 010504 meteorology & atmospheric sciences, Geotraces, General Chemistry, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Water column, Antarctic Bottom Water, Circumpolar deep water, Environmental Chemistry, Hydrography, Thermocline, Geology, 0105 earth and related environmental sciences, Water Science and Technology
Abstract

The 2013 US GEOTRACES Eastern Pacific Zonal Transect (GP16) extended from the Peruvian coast to Tahiti, along a line that fell between 10 and 15°S. This transect sampled the Peruvian oxygen deficient zone (ODZ) and the hydrothermal plume extending from the East Pacific Rise (EPR) for a variety of trace elements and isotopes (TEIs). Here we report nutrient and hydrographic measurements collected on this cruise, as well as results from an Optimum Multiparameter Analysis (OMPA) to quantify the fractional contributions of endmember water masses in each sample. The primary goals of this study were to better understand the distribution of water masses in the eastern tropical Pacific, and to help interpret TEI measurements collected on this cruise, as well as related studies carried out in the region. In the thermocline, Equatorial Subsurface Water (ESSW) dominated the low oxygen waters of the eastern tropical South Pacific, blending into Eastern South Pacific Intermediate Water (ESPIW) and South Pacific Central Water (SPCW) further west. Below the thermocline, distributions of Antarctic Intermediate Water (AAIW) and Equatorial Pacific Intermediate Water (EqPIW) were relatively homogenous along the section between 800 and 1200 m depth. Deeper in the water column, distinct water mass signatures were found on opposite sides of the EPR: southward flowing Pacific Deep Water (PDW) dominated the basin east of the EPR, while the northward flowing Antarctic Bottom Water (AABW) and Lower Circumpolar Deep Water (LCDW) had the strongest contributions on the western side of the EPR. These findings support previous studies that indicate the Peruvian ODZ is largely contained within ESSW and that the EPR plays an important role in steering water mass distributions in the deep waters of the tropical Pacific. Overall, these results agree well with previous water mass analyses in this region and are consistent with the general circulation patterns in the eastern tropical Pacific.

Published
2018

15. Evolution of the south Pacific helium plume over the past three decades

Author

John E. Lupton and William J. Jenkins

Subjects
Geophysics, Oceanography, 010504 meteorology & atmospheric sciences, 010505 oceanography, Geochemistry and Petrology, 01 natural sciences, Archaeology, Geology, 0105 earth and related environmental sciences
Abstract

Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 18 (2017): 1810–1823, doi:10.1002/2017GC006848.

Published
2017

16. Characteristics of meltwater export from Jakobshavn Isbræ and Ilulissat Icefjord

Author

Nicholas Beaird, William J. Jenkins, and Fiammetta Straneo

Subjects
geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Ocean current, Glacier, Fjord, 010502 geochemistry & geophysics, 01 natural sciences, Iceberg, Oceanography, Submarine pipeline, Glacial period, Hydrography, Meltwater, Geology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract

Jakobshavn Isbræ, which terminates in Ilulissat Icefjord, has undergone rapid retreat and is currently the largest contributor to ice-sheet mass loss among Greenland's marine terminating glaciers. Accelerating mass loss is increasing fresh water discharge to the ocean, which can feed back on ice melt, impact marine ecosystems and potentially modify regional and larger scale ocean circulation. Here we present hydrographic observations, including inert geochemical tracers, that allow the first quantitative description of the glacially-modified waters exported from the Jakobshavn/Icefjord system. Observations within the fjord suggest a deep-reaching overturning cell driven by glacial buoyancy forcing. Modified waters containing submarine meltwater (up to 2.5 ± 0.12%), subglacial discharge (up to 6 ± 0.37%) and large portions of entrained ocean waters are seen to exit the fjord and flow north. The exported meltwaters form a buoyant coastal gravity current reaching to 100 m depth and extending 10 km offshore.

Published
2017

17. Volcanic Helium

Author

Mark D. Kurz and William J. Jenkins

Published
2019

18. A comprehensive global oceanic dataset of helium isotope and tritium measurements

Author

Reiner Schlitzer, Wolfgang Roether, Scott C. Doney, Rana A. Fine, Robert M. Key, Peter Schlosser, Philippe Jean-Baptiste, Toshitaka Gamo, Robert Newton, Yuji Sano, Birgit Klein, William J. Jenkins, Michaela Fendrock, John E. Lupton, James H. Swift, Monika Rhein, Woods Hole Oceanographic Institution (WHOI), Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami [Coral Gables], Atmosphere and Ocean Research Institute [Kashiwa-shi] (AORI), The University of Tokyo (UTokyo), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
lcsh:GE1-350, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, lcsh:QE1-996.5, Ocean current, chemistry.chemical_element, 010502 geochemistry & geophysics, Atmospheric sciences, 01 natural sciences, lcsh:Geology, Neon, chemistry, 13. Climate action, Water temperature, Data quality, General Earth and Planetary Sciences, Environmental science, Tritium, 14. Life underwater, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Isotopes of helium, lcsh:Environmental sciences, Helium, 0105 earth and related environmental sciences
Abstract

Tritium and helium isotope data provide key information on ocean circulation, ventilation, and mixing, as well as the rates of biogeochemical processes and deep-ocean hydrothermal processes. We present here global oceanic datasets of tritium and helium isotope measurements made by numerous researchers and laboratories over a period exceeding 60 years. The dataset's DOI is https://doi.org/10.25921/c1sn-9631, and the data are available at https://www.nodc.noaa.gov/ocads/data/0176626.xml (last access: 15 March 2019) or alternately http://odv.awi.de/data/ocean/jenkins-tritium-helium-data-compilation/ (last access: 13 March 2019) and includes approximately 60 000 valid tritium measurements, 63 000 valid helium isotope determinations, 57 000 dissolved helium concentrations, and 34 000 dissolved neon concentrations. Some quality control has been applied in that questionable data have been flagged and clearly compromised data excluded entirely. Appropriate metadata have been included, including geographic location, date, and sample depth. When available, we include water temperature, salinity, and dissolved oxygen. Data quality flags and data originator information (including methodology) are also included. This paper provides an introduction to the dataset along with some discussion of its broader qualities and graphics.

Published
2019

19. A comprehensive global oceanic dataset of helium isotope and tritium measurements

Author

William J. Jenkins, Scott C. Doney, Michaela Fendrock, Rana Fine, Toshitaka Gamo, Philippe Jean-Baptiste, Robert Key, Birgit Klein, John E. Lupton, Monika Rhein, Wolfgang Roether, Yuji Sano, Reiner Schlitzer, Peter Schlosser, and Jim Swift

Abstract

Tritium and helium isotope data provide key information on ocean circulation, ventilation, and mixing, as well as the rates of biogeochemical processes, and deep-ocean hydrothermal processes. We present here global oceanic datasets of tritium and helium isotope measurements made by numerous researchers and laboratories over a period exceeding 60 years. The dataset has a DOI:10.25921/c1sn-9631 and is available at https://www.nodc.noaa.gov/ocads/data/0176626.xml, and includes approximately 60,000 valid tritium measurements, 63,000 valid helium isotope determinations, 57,000 dissolved helium concentrations, and 34,000 dissolved neon concentrations. Some quality control has been applied in that questionable data have been flagged and clearly compromised data excluded entirely. Appropriate metadata has been included, including geographic location, date, and sample depth When available, we include water temperature, salinity, and dissolved oxygen. Data quality flags and data originator information (including methodology) are also included. This paper provides an introduction to the dataset along with some discussion of its broader qualities and graphics.

Published
2018

20. Estimating the recharge properties of the deep ocean using noble gases and helium isotopes

Author

Chris J. Ballentine, Brice Loose, Peter J. Brown, R. Moriarty, Michael P. Meredith, Alberto C. Naveira Garabato, William J. Jenkins, Sinhue Torres Valdes, Loïc Jullion, and Mario Hoppema

Subjects
Weddell Sea Bottom Water, Water mass, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Brine rejection, Groundwater recharge, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Geophysics, Antarctic Bottom Water, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Deep ocean water, Sea ice, 14. Life underwater, Meltwater, Geology, 0105 earth and related environmental sciences
Abstract

The distribution of noble gases and helium isotopes in the dense shelf waters of Antarctica reflect the boundary conditions near the ocean surface: air-sea exchange, sea ice formation and subsurface ice melt. We use a non-linear least-squares solution to determine the value of the recharge temperature and salinity, as well as the excess air injection and glacial meltwater content throughout the water column and in the precursor to Antarctic Bottom Water. The noble gas-derived recharge temperature and salinity in the Weddell Gyre are -1.95 °C and 34.95 psu near 5500 m; these cold, salty recharge values are a result of surface cooling as well as brine rejection during sea ice formation in Antarctic polynyas. In comparison, the global value for deep water recharge temperature is -0.44 °C at 5500 m, which is 1.5 °C warmer than the southern hemisphere deep water recharge temperature, reflecting the contribution from the north Atlantic. The contrast between northern and southern hemisphere recharge properties highlight the impact of sea ice formation on setting the gas properties in southern sourced deep water. Below 1000 m, glacial meltwater averages 3.5 ‰ by volume and represents greater than 50% of the excess neon and argon found in the water column. These results indicate glacial melt has a non-negligible impact on the atmospheric gas content of Antarctic Bottom Water.

Published
2016

21. Long-range transport of hydrothermal dissolved Zn in the tropical South Pacific

Author

Jingfeng Wu, Saeed Roshan, and William J. Jenkins

Subjects
010504 meteorology & atmospheric sciences, Geotraces, chemistry.chemical_element, General Chemistry, Zinc, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Hydrothermal circulation, Nutrient, chemistry, Productivity (ecology), Environmental Chemistry, Sample collection, Transect, Geology, 0105 earth and related environmental sciences, Water Science and Technology, Hydrothermal vent
Abstract

Zinc (Zn) is one of the essential micronutrients that can regulate oceanic primary productivity due to its central roles as a co-factor in carbonic anhydrase and alkaline phosphatase. However, the sources of dissolved Zn to the ocean are poorly understood, mainly because of the difficulties of sample collection and analysis for Zn at very low concentrations in oceanic waters. The prevailing view considers rivers as the major source of dissolved Zn to the ocean. Here we report the dissolved Zn section along a ~ 4500-km transect at approximately 15°S in the tropical South Pacific Ocean along the western segment of the US GEOTRACES EPZT cruise (the GP16 transect). Dissolved Zn exhibits a substantial enrichment emanating from the hydrothermal vents at the axis of the East Pacific Rise to the central South Pacific, ~ 4000 km away. Total dissolved Zn and mantle-derived 3He show a correlation with R2 = 0.71 at depths 2300–2800 m along the transect. It is likely that this correlation can be improved by accounting for the non-uniformity in the non-hydrothermal background of dissolved Zn. After subtracting the non-hydrothermal Zn imprint using Zn Si relationship in the North Pacific, the correlation between “excess” dissolved Zn and mantle-derived 3He improves significantly (R2 = 0.87). The correlation leads to a global hydrothermal Zn flux of 1.75 ± 0.35 g mol yr− 1 that is many-fold higher than the input fluxes estimated by other studies. These results suggest that mantle-derived dissolved Zn dominates the oceanic Zn inventory and that dissolved Zn residence time is much shorter (3000 ± 600 years) than previous input-based estimates (11,000 and 50,000 years) and more consistent with previous removal-based estimate (3000–6000 years). The shorter residence time, the dominance of hydrothermal input and the negligible contribution of dust to the oceanic dissolved Zn inventory imply that changes in the efficiency of particle-associated removal according to changes in oceanic productivity through time may change the oceanic dissolved Zn inventory rapidly. This, in turn, may lead to a divergence between Zn and the nutrients whose oceanic inventories are more affected by dust which can change dramatically on glacial/interglacial timescales.

Published
2016

22. The GEOTRACES Intermediate Data Product 2017

Author

Thomas J. Browning, Hans-Jürgen Brumsack, Katharina Pahnke, Saeed Roshan, Stephanie Owens, Rosie Chance, Peter Croot, Steven van Heuven, Alison E. Hartman, Mercedes López-Lora, Pu Zhang, Heather A. Bouman, Géraldine Sarthou, François Lacan, Robyn E. Tuerena, José Marcus Godoy, Ester Garcia-Solsona, Steven L. Goldstein, Hans A. Slagter, Celia Venchiarutti, A. Russell Flegal, Emily Townsend, Ralph Till, Christopher T. Hayes, Melanie Gault-Ringold, Ros Watson, Peter N. Sedwick, Chandranath Basak, Bronwyn Wake, Loes J. A. Gerringa, Noriko Nakayama, Lars-Eric Heimbürger, Paul J. Morris, François Fripiat, Paul B. Henderson, Chris J. Daniels, Catherine Jeandel, Helen M. Snaith, Patrizia Ziveri, Toshitaka Gamo, Yanbin Lu, Oliver J. Lechtenfeld, Yingzhe Wu, Andreas Wisotzki, Hajime Obata, Cynthia Dumousseaud, Ashley T. Townsend, Sebastian Mieruch, Donna Cockwell, Laurent Bopp, Elena Masferrer Dodas, Bernhard Schnetger, J. K. Klar, Sunil K. Singh, Joaquin E. Chaves, Kuo-Fang Huang, Louise A. Zimmer, Laura F. Robinson, Michiel M Rutgers van der Loeff, Corey Archer, Feifei Deng, Karen Grissom, Robert Rember, Nicholas J. Hawco, Jingfeng Wu, Robert M. Sherrell, Rachel U. Shelley, Jan-Lukas Menzel Barraqueta, E. Malcolm S. Woodward, Fanny Chever, Yuichiro Kumamoto, Hélène Planquette, Dorothea Bauch, Frank Dehairs, Daniel C. Ohnemus, Akira Nishiuchi, Paul D. Quay, Sanjin Mehic, Zichen Xue, Maxi Castrillejo, Brian Peters, Michael J. Ellwood, Stephen R. Rintoul, Tobias Roeske, Jing Zhang, Gretchen J. Swarr, Peng Ho, Ken O. Buesseler, Gwenaelle Moncoiffe, Martin Frank, Maureen E. Auro, Abby Bull, David Kadko, Montserrat Roca-Martí, Maeve C. Lohan, Roulin Khondoker, Patricia Cámara Mor, Melissa Gilbert, Sebastian M. Vivancos, Erin E. Black, Santiago R. Gonzalez, Gideon M. Henderson, David J. Janssen, Sylvain Rigaud, Amandine Radic, Maxence Paul, Cyril Abadie, Ana Aguliar-Islas, Seth G. John, Marie Boye, Evgenia Ryabenko, Abigail E. Noble, Luke Bridgestock, Brian Duggan, Hisayuki Yoshikawa, Jun Nishioka, Kathrin Wuttig, Pieter van Beek, Jana Friedrich, Thomas M. Church, Maija Heller, Stephen J.G. Galer, Pier van der Merwe, Claire P. Till, Xin Yuan Zheng, Henning Fröllje, John Niedermiller, Howie D. Scher, Johnny Stutsman, Patricia Zunino, Christel S. Hassler, Ye Zhao, Tim M. Conway, William M. Landing, Yang Xiang, Katrin Bluhm, Maria T. Maldonado, Elena Chamizo, Sabrina Speich, Claudine H. Stirling, Guillaume Brissebrat, Matthew A. Charette, Jeremy E. Jacquot, Yu-Te Hsieh, Pinghe Cai, Ivia Closset, Yoshiki Sohrin, Ejin George, Jong-Mi Lee, Leopoldo D. Pena, Edward Mawji, Damien Cardinal, Catherine Pradoux, Martin Q. Fleisher, Virginie Sanial, Derek Vance, Craig A. Carlson, Pere Masqué, Katlin L. Bowman, Evaline M. van Weerlee, Oliver Baars, Ruifang C. Xie, María Villa-Alfageme, Hein J W de Baar, M. Alexandra Weigand, Tina van de Flierdt, J. Bown, Timothy C. Kenna, Kenneth W. Bruland, Jeroen E. Sonke, Hai Cheng, Mark J. Warner, Sven Ober, Rob Middag, Jessica N. Fitzsimmons, Emilie Le Roy, Yishai Weinstein, Nicholas R. Bates, Joerg Rickli, Daniel M. Sigman, Hendrik M. van Aken, Angela Milne, Cheryl M. Zurbrick, Gregory A. Cutter, Igor Semiletov, Marie Labatut, Torben Stichel, Pascale Lherminier, Gabriel Dulaquais, Jay T. Cullen, Christopher I. Measures, Mark Rosenberg, Tomoharu Minami, Mariko Hatta, Alexander L. Thomas, Gonzalo Carrasco, Karel Bakker, Clifton S. Buck, Maarten B Klunder, Willard S. Moore, Reiner Schlitzer, Tomas A. Remenyi, Susan H. Little, Eberhard Fahrbach, Charles R. McClain, Edward A. Boyle, Ursula Schauer, Linjie Zheng, Alex R. Baker, Emma Slater, Kay Thorne, Patrick Laan, Christina Schallenberg, Reiner Steinfeldt, Benjamin S. Twining, Yolanda Echegoyen-Sanz, Neil J. Wyatt, Alison M. Agather, Viena Puigcorbé, Peter Scott, Gillian Stewart, Matthew P. Humphreys, Frédéric A. C. Le Moigne, Phoebe J. Lam, Núria Casacuberta, Josh Helgoe, Edward C.V. Butler, Mark Rehkämper, Elizabeth M. Jones, Karen L. Casciotti, James W. Moffett, Tristan J. Horner, Sue Velazquez, Yuzuru Nakaguchi, Micha J.A. Rijkenberg, Antje H L Voelker, Joseph A. Resing, Lesley Salt, Eric P. Achterberg, Sven Kretschmer, Jan van Ooijen, Dominik J. Weiss, Moritz Zieringer, Carl H. Lamborg, Rick Kayser, Pierre Branellec, John M. Rolison, Sara Rauschenberg, Walter Geibert, Raja S. Ganeshram, Myriam Lambelet, Janice L. Jones, Chad R. Hammerschmidt, William J. Jenkins, Jordi Garcia-Orellana, Alessandro Tagliabue, Philip W. Boyd, Alan M. Shiller, Marcus Christl, Mark Baskaran, Mak A. Saito, Huong Thi Dieu, Morten B. Andersen, Kenji Isshiki, Taejin Kim, Christian Schlosser, Melanie K. Behrens, Albert S. Colman, Frédéric Planchon, Bettina Sohst, Andrew R. Bowie, Mark A. Brzezinski, R. Lawrence Edwards, Kristen N. Buck, Jeanette O'Sullivan, William M. Smethie, Wafa Abouchami, Valentí Rodellas, Ed C Hathorne, Robert F. Anderson, James H. Swift, Frank J. Pavia, Daniel Cossa, Lauren Kipp, Peter L. Morton, Fabien Quéroué, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Centre for Automotive Safety Research, University of Adelaide, University of California, National Oceanography Centre (NOC), Scottish Association for Marine Science (SAMS), Department of Oceanography [Cape Town], University of Cape Town, Antarctic Climate and Ecosystems Cooperative Research Centre (ACE-CRC), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Chemistry (MPIC), Max-Planck-Gesellschaft, University of Toyama, Department of Marine Chemistry and Geochemistry (WHOI), Woods Hole Oceanographic Institution (WHOI), Royal Netherlands Institute for Sea Research (NIOZ), Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Department of Geology, Wayne State University [Detroit], The Bartlett, University College of London [London] (UCL), Institute for Environmental Research, Rheinisch-Westfälische Technische Hochschule Aachen (RWTH), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Department of Earth Sciences [Oxford], University of Oxford [Oxford], Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Cycles biogéochimiques marins : processus et perturbations (CYBIOM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institute for Research on Learning, Services communs OMP - UMS 831 (UMS 831), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Marine Science Institute [Santa Barbara] (MSI), University of California [Santa Barbara] (UCSB), University of California-University of California, National Oceanography Centre [Southampton] (NOC), University of Southampton, Institut Français de Recherche pour l'Exploitation de la Mer - Nantes (IFREMER Nantes), Université de Nantes (UN), University of Victoria [Canada] (UVIC), Massachusetts Institute of Technology (MIT), Universidad de Dakota del Sur, Analytical, Environmental and Geo- Chemistry, Vrije Universiteit [Brussels] (VUB), Wright State University, School of Geography, Earth and Environmental Sciences [Plymouth] (SoGEES), Plymouth University, Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], Alfred Wegener Institute [Potsdam], Institute of Global Environmental Change [China] (IGEC), Xi'an Jiaotong University (Xjtu), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Department of Mathematics and Science, National Taiwan Normal University (NTNU), School of Information Technology [Kharagpur], Indian Institute of Technology Kharagpur (IIT Kharagpur), GEOMAR - Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), University of California [Davis] (UC Davis), Institut de Ciencia i Tecnologia Ambientals (ICTA), Universitat Autònoma de Barcelona [Barcelona] (UAB), Institute of Low Temperature Science, Hokkaido University, The University of Tokyo, Institute for Marine and Antarctic Studies [Horbat] (IMAS), University of Tasmania (UTAS), Joint Institute for the Study of the Atmosphere and Ocean (JISAO), University of Washington [Seattle], Institute of Geochemistry and Petrology, Détection, évaluation, gestion des risques CHROniques et éMErgents (CHROME) / Université de Nîmes (CHROME), Université de Nîmes (UNIMES), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), School of Earth and Ocean Sciences, University of Victoria, Knowledge Media Institute (KMI), The Open University [Milton Keynes] (OU), Bermuda Biological Station for Research (BBSR), Bermuda Biological Station for Research, Department of Geosciences [Princeton], Princeton University, Kyoto University [Kyoto], Géochimie des Isotopes Stables (GIS), Géosciences Environnement Toulouse (GET), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES), School of Earth and Environmental Sciences [Queens New York], Queens College [New York], City University of New York [New York] (CUNY)-City University of New York [New York] (CUNY), SOEST, University of Hawai‘i [Mānoa] (UHM), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Bigelow Laboratory for Ocean Sciences, Department of Earth Science and Technology [Imperial College London], Imperial College London, Plymouth Marine Laboratory, Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami [Coral Gables], Tsinghua National Laboratory for Information Science and Technology (TNList), RITE, Research Institute of Innovative Technology for the Earth, Agricultural Information Institute (AII), Chinese Academy of Agricultural Sciences (CAAS), Department of Mathematics [Shanghai], Shanghai Jiao Tong University [Shanghai], University of California [Irvine] (UCI), Institute of Environmental Science and Technology [Barcelona] (ICTA), University of California (UC), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Rheinisch-Westfälische Technische Hochschule Aachen University (RWTH), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), University of Oxford, Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Southern California (USC), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Services communs OMP (UMS 831), Université Toulouse III - Paul Sabatier (UT3), Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France, University of California [Santa Barbara] (UC Santa Barbara), University of California (UC)-University of California (UC), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Vrije Universiteit Brussel (VUB), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Florida International University [Miami] (FIU), Department of Earth Science and Engineering [Imperial College London], Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Universitat Autònoma de Barcelona (UAB), British Oceanographic Data Centre (BODC), Institute of Low Temperature Science [Sapporo], Hokkaido University [Sapporo, Japan], The University of Tokyo (UTokyo), Institute of Geochemistry and Petrology [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), College of Earth, Ocean, and Environment [Newark] (CEOE), University of Delaware [Newark], Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Knowledge Media Institute (KMi), Kyoto University, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Academia Sinica, University of California [Irvine] (UC Irvine), Danish Technological Institute (DTI), Scientific Committee on Oceanic Research (SCOR) from the U.S. National Science Foundation [OCE-0608600, OCE-0938349, OCE-1243377, OCE-1546580], UK Natural Environment Research Council (NERC), Ministry of Earth Science of India, Centre National de Recherche Scientifique, l'Universite Paul Sabatier de Toulouse, Observatoire Midi-Pyrenees Toulouse, Universitat Autonoma de Barcelona, Kiel Excellence Cluster The Future Ocean, Swedish Museum of Natural History, University of Tokyo, University of British Columbia, Royal Netherlands Institute for Sea Research, GEOMAR-Helmholtz Centre for Ocean Research Kiel, Alfred Wegener Institute, Scientific Committee on Oceanic Research, National Science Foundation (US), Natural Environment Research Council (UK), Ministry of Earth Sciences (India), Centre National de la Recherche Scientifique (France), Université Toulouse III Paul Sabatier, Observatoire Midi-Pyrénées (France), Universidad Autónoma de Barcelona, Helmholtz Centre for Ocean Research Kiel, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (Germany), Schlitzer, Reiner [0000-0002-3740-6499], Masferrer Dodas, Elena [0000-0003-0879-1954], Chamizo, Elena [0000-0001-8266-6129], Christl, M. [0000-0002-3131-6652], Masqué, Pere [0000-0002-1789-320X], Villa-Alfageme, María [0000-0001-7157-8588], Universitat de Barcelona, Natural Environment Research Council (NERC), Leverhulme Trust, Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Carrasco Rebaza, Gonzalo, Echegoyen Sanz, Yolanda, Kayser, Richard A, Isotope Research, Ocean Ecosystems, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Hassler, Christel, Schlitzer, Reiner, Masferrer Dodas, Elena, Chamizo, Elena, Christl, M., Masqué, Pere, and Villa-Alfageme, María

Subjects
Geochemistry & Geophysics, 010504 meteorology & atmospheric sciences, Isòtops, sub-01, Geotraces, MODELS, Digital data, Context (language use), 010502 geochemistry & geophysics, 01 natural sciences, IDP2017, Isotopes, Geochemistry and Petrology, Oceans, Electronic atlas, ddc:550, 0402 Geochemistry, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, NetCDF, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Trace elements, Science & Technology, Information retrieval, ACL, Geology, computer.file_format, Ocean Data View, Metadata, Data processing, GEOTRACES, 0403 Geology, Data extraction, 13. Climate action, Data quality, Physical Sciences, [SDE]Environmental Sciences, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, 0406 Physical Geography and Environmental Geoscience, computer, Processament de dades, Trace elements Isotopes
Abstract

The GEOTRACES Intermediate Data Product 2017 (IDP2017) is the second publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2016. The IDP2017 includes data from the Atlantic, Pacific, Arctic, Southern and Indian oceans, with about twice the data volume of the previous IDP2014. For the first time, the IDP2017 contains data for a large suite of biogeochemical parameters as well as aerosol and rain data characterising atmospheric trace element and isotope (TEI) sources. The TEI data in the IDP2017 are quality controlled by careful assessment of intercalibration results and multi-laboratory data comparisons at crossover stations. The IDP2017 consists of two parts: (1) a compilation of digital data for more than 450 TEIs as well as standard hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing an on-line atlas that includes more than 590 section plots and 130 animated 3D scenes. The digital data are provided in several formats, including ASCII, Excel spreadsheet, netCDF, and Ocean Data View collection. Users can download the full data packages or make their own custom selections with a new on-line data extraction service. In addition to the actual data values, the IDP2017 also contains data quality flags and 1-σ data error values where available. Quality flags and error values are useful for data filtering and for statistical analysis. Metadata about data originators, analytical methods and original publications related to the data are linked in an easily accessible way. The eGEOTRACES Electronic Atlas is the visual representation of the IDP2017 as section plots and rotating 3D scenes. The basin-wide 3D scenes combine data from many cruises and provide quick overviews of large-scale tracer distributions. These 3D scenes provide geographical and bathymetric context that is crucial for the interpretation and assessment of tracer plumes near ocean margins or along ridges. The IDP2017 is the result of a truly international effort involving 326 researchers from 25 countries. This publication provides the critical reference for unpublished data, as well as for studies that make use of a large cross-section of data from the IDP2017. This article is part of a special issue entitled: Conway GEOTRACES - edited by Tim M. Conway, Tristan Horner, Yves Plancherel, and Aridane G. González., National Science Foundation (U.S.) (Grant OCE-0608600), National Science Foundation (U.S.) (Grant OCE0938349), National Science Foundation (U.S.) (Grant OCE-1243377), National Science Foundation (U.S.) (Grant OCE-1546580)

Published
2018

23. The 3He flux gauge in the Sargasso Sea: a determination of physical nutrient fluxes to the euphotic zone at the Bermuda Atlantic Time-series Site

Author

Scott C. Doney, Dempsey E. Lott, Rachel H. R. Stanley, and William J. Jenkins

Subjects
Water mass, Mixed layer, New production, chemistry.chemical_compound, Oceanography, Flux (metallurgy), Nitrate, chemistry, Mode water, Photic zone, 14. Life underwater, Thermocline, Ecology, Evolution, Behavior and Systematics, Geology, Earth-Surface Processes
Abstract

Significant rates of primary production occur in the oligotrophic ocean, without any measurable nutrients present in the mixed layer, fueling a scientific paradox that has lasted for decades. Here, we provide a new determination of the annual mean physical supply of nitrate to the euphotic zone in the western subtropical North Atlantic. We combine a 3-year time series of measurements of tritiugenic 3He from 2003 to 2006 in the surface ocean at the Bermuda Atlantic Time-series Study (BATS) site with a sophisticated noble gas calibrated air–sea gas exchange model to constrain the 3He flux across the sea–air interface, which must closely mirror the upward 3He flux into the euphotic zone. The product of the 3He flux and the observed subsurface nitrate–3He relationship provides an estimate of the minimum rate of new production in the BATS region. We also apply the gas model to an earlier time series of 3He measurements at BATS in order to recalculate new production fluxes for the 1985 to 1988 time period. The observations, despite an almost 3-fold difference in the nitrate–3He relationship, yield a roughly consistent estimate of nitrate flux. In particular, the nitrate flux from 2003 to 2006 is estimated to be 0.65 ± 0.14 mol m−2 yr−1, which is ~40 % smaller than the calculated flux for the period from 1985 to 1988. The difference in nitrate flux between the time periods may be signifying a real difference in new production resulting from changes in subtropical mode water formation. Overall, the nitrate flux is larger than most estimates of export fluxes or net community production fluxes made locally for the BATS site, which is likely a reflection of the larger spatial scale covered by the 3He technique and potentially also by the decoupling of 3He and nitrate during the obduction of water masses from the main thermocline into the upper ocean. The upward nitrate flux is certainly large enough to support observed rates of primary production at BATS and more generally in the oligotrophic subtropical ocean.

Published
2015

24. Water mass analysis for the U.S. GEOTRACES (GA03) North Atlantic sections

Author

William M. Smethie, William J. Jenkins, Edward A. Boyle, and Gregory A. Cutter

Subjects
Water mass, Oceanography, Geotraces, Circumpolar deep water, Ocean current, North Atlantic Deep Water, Thermohaline circulation, Mid-Atlantic Ridge, Hydrography, Geology
Abstract

We present the distributions of hydrographic properties (potential temperature, salinity, dissolved oxygen, and micromolar level inorganic macronutrients) along two sections occupied in the subtropical North Atlantic as part of the first U.S. GEOTRACES (GA03) survey during 2010 and 2011. The purpose of this work is to place subsequent papers in this special issue in a general context and to provide a framework in which the observed distributions of Trace Elements and Isotopes can be interpreted. Using these hydrographic properties we use a modified Optimum Multiparameter water mass analysis method to diagnose the relative contributions of various water types along the sections and rationalize their distributions. The water mass compositions appear largely consistent with what is understood from previous studies about the large scale circulation and ventilation of the North Atlantic, with perhaps one exception. We found that the North Atlantic Deep water both east and west of the Mid Atlantic Ridge is more strongly influenced by Iceland Scotland Overflow Water relative to Denmark Straits Overflow Water (about 3:1) than inferred from other tracer studies (typically 2:1). It remains unclear whether this is an artifact of our calculation or a real change in deep water composition in the decades between the determinations.

Published
2015

25. The distributions of helium isotopes and tritium along the U.S. GEOTRACES North Atlantic sections (GEOTRACES GAO3)

Author

William J. Jenkins, Brett E. Longworth, K.L. Cahill, J.M. Curtice, and Dempsey E. Lott

Subjects
geography, Oceanography, Water column, geography.geographical_feature_category, Volcano, Geotraces, Upwelling, Isotopes of helium, Thermocline, Geology, Boundary current, Plume
Abstract

We present the distributions of helium isotopes (in the form of helium isotope ratio anomaly relative to the atmospheric ratio) and tritium along two sections occupied in the subtropical North Atlantic as part of the first U.S. GEOTRACES survey (GEOTRACES GA03). The general distributions of these isotopes are consistent with the continuing penetration and evolution of bomb-produced tritium and its daughter isotope 3He in the main thermocline and along the western boundary current system. We combine these two distributions to compute a tritium–3He age, which is related to the elapsed time since the water was at the ocean surface. Although it is an indicator biased by the effects of mixing and influenced by the time history and spatial distribution of bomb tritium delivery to the ocean surface, it still remains a useful measure of ventilation time-scales. Aside from the continued propagation of the tritium–3He transient into the ocean interior, there are three notable features of interest in these distributions. The first is the clear signature of upwelling in the water column near the coast of Mauritania, characterized by the upward bowing of isochrones in the thermocline and discernable 3He excess at the ocean surface. A simple 3He mass balance calculation suggests an upwelling flux of order 1.8×106 m3 s−1 (1.8 Sv) along the Mauritanian coast. The second is a mid-depth (~1500–2000 m) core of ventilated waters centered over the Mid-Atlantic Ridge, an anticyclonic circulation of waters likely originating in the Labrador Sea. The third notable feature is a volcanic 3He plume at about 3500 m depth emanating from the TAG Hydrothermal Area that is detectable as much as 500 km away on each side of the Mid-Atlantic Ridge. We estimate a 3He:heat ratio of ~7×10–18 mol J−1 and a 3He flux from the TAG site of ~15 mmol y−1. Since 3He is a conserved tracer in the absence of measureable tritium, the correlation of volcanic 3He with other hydrothermally influenced TEIs (e.g., Fe) can be used as a dilution tracer as probe of non-conservative behavior in the water column. Also, since the regional and global fluxes of volcanic 3He are known, the correlations can be used as a regional/global flux gauge for hydrothermal input of those TEIs.

Published
2015

27. An Analysis of Amos Tversky and Daniel Kahneman's Judgment Under Uncertainty : Heuristics and Biases

Author

Camille Morvan, William J. Jenkins, Camille Morvan, and William J. Jenkins

Subjects
Reasoning--Testing
Abstract

Amos Tversky and Daniel Kahneman's 1974 paper ‘Judgement Under Uncertainty: Heuristics and Biases'is a landmark in the history of psychology. Though a mere seven pages long, it has helped reshape the study of human rationality, and had a particular impact on economics – where Tversky and Kahneman's work helped shape the entirely new sub discipline of ‘behavioral economics.'The paper investigates human decision-making, specifically what human brains tend to do when we are forced to deal with uncertainty or complexity. Based on experiments carried out with volunteers, Tversky and Kahneman discovered that humans make predictable errors of judgement when forced to deal with ambiguous evidence or make challenging decisions. These errors stem from ‘heuristics'and ‘biases'– mental shortcuts and assumptions that allow us to make swift, automatic decisions, often usefully and correctly, but occasionally to our detriment. The paper's huge influence is due in no small part to its masterful use of high-level interpretative and analytical skills – expressed in Tversky and Kahneman's concise and clear definitions of the basic heuristics and biases they discovered. Still providing the foundations of new work in the field 40 years later, the two psychologists'definitions are a model of how good interpretation underpins incisive critical thinking.

Published
2017

28. An Analysis of Michael R. Gottfredson and Travish Hirschi's A General Theory of Crime

Author

William J Jenkins and William J Jenkins

Subjects
Criminal psychology, Self-control, Criminology--History
Abstract

Michael R. Gottfredson and Travish Hirschi's 1990 A General Theory of Crime is a classic text that helped reshape the discipline of criminology. It is also a testament to the powers of clear reasoning and interpretation. In critical thinking terms, reasoning is all about presenting a solid and persuasive case – and as many people instinctively understand, the most persuasive reasoning is that which bases itself on a single, simple hook. In Gottfredson and Hirschi's case, this hook was what has come to be known as the “self-control theory of crime” – the idea that the tendency to commit crime is directly related to an individual's level of self-control. While the dominant schools of thought of the time tended to focus on crime as the product of complex environmental factors, with little attempt to unify different theories, Gottfredson and Hirschi sought to interpret things so as to provide a single overarching concept that explained why crimes of all sorts were committed. Moreover, while other theories of crime concentrated on understanding and explaining specific types of law-breaking, the self-control model could, in Gottfredson and Hirschi's view, be seen as the basis for understanding the root cause for all crime in all contexts. While such simplicity inevitably attracted as much criticism as agreement, subsequent studies have provided real-world corroboration for the General Theory's persuasive reasoning.

Published
2017

29. An Analysis of Stanley Milgram's Obedience to Authority : An Experimental View

Author

Mark Gridley, William J. Jenkins, Mark Gridley, and William J. Jenkins

Subjects
Psychology--Experiments, Authority, Obedience--Moral and ethical aspects, Compliance
Abstract

Stanley Milgram is one of the most influential and widely-cited social psychologists of the twentieth century. Recognized as perhaps the most creative figure in his field, he is famous for crafting social-psychological experiments with an almost artistic sense of creative imagination – casting new light on social phenomena in the process. His 1974 study Obedience to Authority exemplifies creative thinking at its most potent, and controversial. Interested in the degree to which an “authority figure” could encourage people to commit acts against their sense of right and wrong, Milgram tricked volunteers for a “learning experiment” into believing that they were inflicting painful electric shocks on a person in another room. Able to hear convincing sounds of pain and pleas to stop, the volunteers were told by an authority figure – the “scientist” – that they should continue regardless. Contrary to his own predictions, Milgram discovered that, depending on the exact set up, as many as 65% of people would continue right up to the point of “killing” the victim.The experiment showed, he believed, that ordinary people can, and will, do terrible things under the right circumstances, simply through obedience. As infamous and controversial as it was creatively inspired, the “Milgram experiment” shows just how radically creative thinking can shake our most fundamental assumptions.

Published
2017

30. An Analysis of Elizabeth F. Loftus's Eyewitness Testimony

Author

William J Jenkins and William J Jenkins

Subjects
Witnesses, Eyewitness accounts, Memory, Recollection (Psychology)
Abstract

Understanding evidence is critical in a court of law – and it is just as important for critical thinking. Elizabeth Loftus, a pioneering psychologist, made a landmark contribution to both these areas in Eyewitness Testimony, a trail-blazing work that undermines much of the decision-making made by judges and juries by pointing out how flawed eyewitness testimony actually is. Reporting the results of an eye-opening series of experiments and trials, Loftus explores the ways in which – unbeknownst to the witnesses themselves – memory can be distorted and become highly unreliable. Much of Loftus's work is based on expert use of the critical thinking skill of interpretation. Her work not only highlights multiple problems of definition with regard to courtroom testimony, but also focuses throughout on how best we can understand the meaning of the available evidence. Eyewitness Testimony is arguably the best place in the Macat library to begin any investigation of how to use and understand interpretation.

Published
2017

31. An Analysis of Sigmund Freud's The Interpretation of Dreams

Author

William J Jenkins and William J Jenkins

Subjects
Psychoanalysis, Dream interpretation
Abstract

There is arguably no more famous book about the arts of interpretation and analysis than Sigmund Freud's 1899 Interpretation of Dreams. Though the original edition of just 600 copies took eight years to sell out, it eventually became a classic text that helped cement Freud's reputation as one of the most significant intellectual figures of the 19th and 20th centuries. In critical thinking, just as in Freud's psychoanalytical theories, interpretation is all about understanding the meaning of evidence, and tracing the significance of things. Analysis can then be brought in to tease out the implicit reasons and assumptions that lie underneath the interpreted evidence. Interpretation of Dreams is a masterclass in building telling analyses from ingenious interpretation of evidence. Freud worked from the assumption that all dreams were significant attempts by the unconscious to resolve conflicts. As a result, he argued, they contain in altered and disguised forms clues to our deepest unconscious urges and desires. Each must be taken on its own terms to tease out what they really mean. Though Freud's theories have often been criticized, he remains the undisputed master of interpretation – with his critics suggesting that he was, if anything, too ingenious for his own good.

Published
2017

32. Distal transport of dissolved hydrothermal iron in the deep South Pacific Ocean

Author

Jessica N. Fitzsimmons, Edward A. Boyle, and William J. Jenkins

Subjects
Abyssal zone, Multidisciplinary, Oceanography, Geography, Commentaries, fungi, Physical Sciences, Flux, Pacific ocean, geographic locations, Hydrothermal circulation, Hydrothermal vent, Aerosol
Abstract

Until recently, hydrothermal vents were not considered to be an important source to the marine dissolved Fe (dFe) inventory because hydrothermal Fe was believed to precipitate quantitatively near the vent site. Based on recent abyssal dFe enrichments near hydrothermal vents, however, the leaky vent hypothesis [Toner BM, et al. (2012) Oceanography 25(1):209-212] argues that some hydrothermal Fe persists in the dissolved phase and contributes a significant flux of dFe to the global ocean. We show here the first, to our knowledge, dFe (0.4 µm) measurements from the abyssal southeast and southwest Pacific Ocean, where dFe of 1.0-1.5 nmol/kg near 2,000 m depth (0.4-0.9 nmol/kg above typical deep-sea dFe concentrations) was determined to be hydrothermally derived based on its correlation with primordial (3)He and dissolved Mn (dFe:(3)He of 0.9-2.7 × 10(6)). Given the known sites of hydrothermal venting in these regions, this dFe must have been transported thousands of kilometers away from its vent site to reach our sampling stations. Additionally, changes in the size partitioning of the hydrothermal dFe between soluble (0.02 µm) and colloidal (0.02-0.4 µm) phases with increasing distance from the vents indicate that dFe transformations continue to occur far from the vent source. This study confirms that although the southern East Pacific Rise only leaks 0.02-1% of total Fe vented into the abyssal Pacific, this dFe persists thousands of kilometers away from the vent source with sufficient magnitude that hydrothermal vents can have far-field effects on global dFe distributions and inventories (≥3% of global aerosol dFe input).

Published
2014

33. Carbonation rates of peridotite in the Samail Ophiolite, Sultanate of Oman, constrained through 14C dating and stable isotopes

Author

Susan E. Humphris, Evelyn M. Mervine, William J. Jenkins, Kenneth W.W. Sims, and Peter B. Kelemen

Subjects
Peridotite, Outcrop, Stable isotope ratio, Geochemistry, Mineralogy, Weathering, Ophiolite, chemistry.chemical_compound, chemistry, Geochemistry and Petrology, Period (geology), Carbonate, Deposition (chemistry), Geology
Abstract

Detailed 14 C dating as well as stable C and O isotope analyses were conducted on carbonates formed during alteration of the peridotite layer of the Samail Ophiolite, Sultanate of Oman. 14 C results obtained in this and previous studies indicate that surface travertines range in age from modern to >45,000 yr BP, indicating long-term deposition and preservation. Travertine deposition rates in two localities were ∼0.1 to 0.3 mm/yr between ∼30,000 and 45,000 yr BP. Using an estimate of total travertine area, this would result in a maximum of ∼1000 to 3000 m 3 /yr of travertine being deposited throughout the ophiolite during this time period. This travertine deposition would have sequestered a maximum of ∼1 to 3 × 10 6 kg CO 2 /yr. Ca-rich carbonate veins that are associated with the surface travertine deposits have ages ranging from ∼4000 to 36,000 yr BP (average: 15,000 yr BP). Mg-rich carbonate veins exposed in outcrops have ages ranging from ∼8000 to 45,000 yr BP (average: 35,000 yr BP). Detailed sampling from numerous locations (3 locations in this study and 10 locations in the previous studies) indicates that no carbonate veins from the natural peridotite weathering surface are older than the ∼50,000 yr BP dating limit of 14 C. However, 14 C dating of Mg-rich carbonate veins from three roadcut exposures (Qafeefah, Fanja, and Al-Wuqbah) indicates that a significant number of roadcut veins are 14 C dead (>50,000 yr BP). A location weighted average indicates that ∼40% of veins sampled at the three roadcuts are 14 C dead. An average including veins sampled at both roadcuts and outcrops indicates that overall ∼8% of Mg-rich carbonate veins are 14 C dead. Mg-rich carbonate veins are estimated to sequester on the order of 10 7 kg CO 2 /yr throughout the ophiolite.

Published
2014

34. Slow-spreading submarine ridges in the South Atlantic as a significant oceanic iron source

Author

Tyler J. Goepfert, Abigail E. Noble, Carl H. Lamborg, William J. Jenkins, Mak A. Saito, and Alessandro Tagliabue

Subjects
Oceanography, Dissolved iron, fungi, Hydrothermal plume, General Earth and Planetary Sciences, Submarine, Seawater, Geology, Iron source
Abstract

Low levels of the micronutrient iron limit primary production and nitrogen fixation in large areas of the global ocean. Measurements in the South Atlantic suggest that slow-spreading submarine ridges serve as a significant oceanic iron source in these waters.

Published
2013

35. Movement of deep-sea coral populations on climatic timescales

Author

Mark L. Roberts, Dana Gerlach, Adam V. Subhas, Jess F. Adkins, William J. Jenkins, Andrea Burke, Ann P. McNichol, Ronald E. Thresher, and Nivedita Thiagarajan

Subjects
education.field_of_study, geography, geography.geographical_feature_category, Ecology, Coral, Population, Seamount, Paleontology, Climate change, Last Glacial Maximum, Oceanography, Deglaciation, Glacial period, education, Geology, Holocene
Abstract

During the past 40,000 years, global climate has moved into and out of a full glacial period, with the deglaciation marked by several millennial-scale rapid climate change events. Here we investigate the ecological response of deep-sea coral communities to both glaciation and these rapid climate change events. We find that the deep-sea coral populations of Desmophyllum dianthus in both the North Atlantic and the Tasmanian seamounts expand at times of rapid climate change. However, during the more stable Last Glacial Maximum, the coral population globally retreats to a more restricted depth range. Holocene populations show regional patterns that provide some insight into what causes these dramatic changes in population structure. The most important factors are likely responses to climatically driven changes in productivity, [O_2] and [CO_3^(2–)].

Published
2013

36. Improved Precision of Radiocarbon Measurements for CH4 and CO2 Using GC and Continuous-Flow AMS Achieved by Summation of Repeated Injections

Author

Ann P. McNichol, Karl F. von Reden, Cameron McIntyre, William J. Jenkins, Jeffrey S. Seewald, and Mark L. Roberts

Subjects
010506 paleontology, Archeology, 060102 archaeology, Continuous flow, Compound specific, Analytical chemistry, 06 humanities and the arts, 01 natural sciences, Methane, Ion source, law.invention, chemistry.chemical_compound, chemistry, law, Carbon dioxide, Calibration, General Earth and Planetary Sciences, 0601 history and archaeology, Radiocarbon dating, Gas chromatography, 0105 earth and related environmental sciences
Abstract

Compound specific radiocarbon measurements can be made instantaneously using a gas chromatograph (GC) combustion system coupled to a 14C AMS system fitted with a gas ion source. Samples below 10 μg C can be analyzed but the precision is reduced to 5–10% because of lower source efficiency. We modified our GC for CH4 and CO2 analysis and injected samples multiple times to sum data and increase precision. We attained a maximum precision of 0.6% for modern CO2 from 25 injections of 27 μg C and a background of ≃0.5% (40 kyr) for ancient methane. The 14C content of dissolved CO2 and CH4 in water samples collected at a deep-sea hydrothermal vent and a serpentine mud volcano was measured and the results for the vent sample are consistent with previously published data. Further experiments are required to determine a calibration and correction procedure to maximize accuracy.

Published
2013

37. Carbonate as sputter target material for rapid 14C AMS

Author

Laura F. Robinson, Andrea Burke, William J. Jenkins, Brett E. Longworth, Mark L. Roberts, and Steven R. Beaupré

Subjects
Nuclear and High Energy Physics, education.field_of_study, Population, Analytical chemistry, chemistry.chemical_element, Ion source, Titanium powder, chemistry.chemical_compound, chemistry, Sputtering, Carbonate, Graphite, education, Instrumentation, Carbon, Accelerator mass spectrometry
Abstract

This paper describes a technique for measuring the 14C content of carbonate samples by producing C− ions directly in the negative ion sputter source of an accelerator mass spectrometer (AMS) system. This direct analysis of carbonate material eliminates the time and expense of graphite preparation. Powdered carbonate is mixed with titanium powder, loaded into a target cartridge, and compressed. Beam currents for optimally-sized carbonate targets (0.09–0.15 mg C) are typically 10–20% of those produced by optimally-sized graphite targets (0.5–1 mg C). Modern (>0.8 Fm) samples run by this method have standard deviations of 0.009 Fm or less, and near-modern samples run as unknowns agree with values from traditional hydrolysis/graphite to better than 2%. Targets with as little as 0.06 mg carbonate produce useable ion currents and results, albeit with increased error and larger blank. In its current state, direct sputtering is best applied to problems where a large number of analyses with lower precision are required. These applications could include age surveys of deep-sea corals for determination of historic population dynamics, to identify samples that would benefit from high precision analysis, and for growth rate studies of organisms forming carbonate skeletons.

Published
2013

38. Hydrothermal impacts on trace element and isotope ocean biogeochemistry

Author

Reiner Schlitzer, Rachel A. Mills, Hajime Obata, Christopher R. German, Jean-Claude Dutay, Hannah Whitby, Lars-Eric Heimbürger, David Turner, Karen L. Casciotti, William J. Jenkins, Christopher I. Measures, Alessandro Tagliabue, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation du climat (CLIM), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Atmosphere and Ocean Research Institute [Kashiwa-shi] (AORI), The University of Tokyo (UTokyo), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Southern Ocean Carbon and Climate observatory, CSIR, Department of Health and Human Services, National Institutes of Health [Bethesda] (NIH), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Biogeochemical cycle, 010504 meteorology & atmospheric sciences, General Mathematics, Geotraces, [SDE.MCG]Environmental Sciences/Global Changes, General Physics and Astronomy, trace elements and isotopes, 010502 geochemistry & geophysics, 01 natural sciences, Hydrothermal circulation, hydrothermal activity, 14. Life underwater, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, General Engineering, Trace element, Biogeochemistry, Articles, ocean biogeochemistry, Seafloor spreading, Oceanography, GEOTRACES, 13. Climate action, Environmental science, Thermohaline circulation, Oceanic basin, Research Article
Abstract

Hydrothermal activity occurs in all ocean basins, releasing high concentrations of key trace elements and isotopes (TEIs) into the oceans. Importantly, the calculated rate of entrainment of the entire ocean volume through turbulently mixing buoyant hydrothermal plumes is so vigorous as to be comparable to that of deep-ocean thermohaline circulation. Consequently, biogeochemical processes active within deep-ocean hydrothermal plumes have long been known to have the potential to impact global-scale biogeochemical cycles. More recently, new results from GEOTRACES have revealed that plumes rich in dissolved Fe, an important micronutrient that is limiting to productivity in some areas, are widespread above mid-ocean ridges and extend out into the deep-ocean interior. While Fe is only one element among the full suite of TEIs of interest to GEOTRACES, these preliminary results are important because they illustrate how inputs from seafloor venting might impact the global biogeochemical budgets of many other TEIs. To determine the global impact of seafloor venting, however, requires two key questions to be addressed: (i) What processes are active close to vent sites that regulate the initial high-temperature hydrothermal fluxes for the full suite of TEIs that are dispersed through non-buoyant hydrothermal plumes? (ii) How do those processes vary, globally, in response to changing geologic settings at the seafloor and/or the geochemistry of the overlying ocean water? In this paper, we review key findings from recent work in this realm, highlight a series of key hypotheses arising from that research and propose a series of new GEOTRACES modelling, section and process studies that could be implemented, nationally and internationally, to address these issues. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’.

Published
2016

39. GEOTRACES - An international study of the global marine biogeochemical cycles of trace elements and their isotopes

Author

M. M. Rutgers van der Loeff, Raymond T. Pollard, Greg Cutter, K. von Damm, Jing Zhang, Toshitaka Gamo, J. K. Moore, Martin Frank, Morse Hall, William J. Jenkins, P. Masque, H. J. W. de Baar, Jess F. Adkins, Gideon M. Henderson, Edward A. Boyle, Andreas Oschlies, Anton Eisenhauer, Roger Francois, Kristin J. Orians, Mukul Sharma, Robert F. Anderson, D. Mackey, Catherine Jeandel, P.S. Andersson, Reiner Schlitzer, S. Krishnaswami, Tim Jickells, Christopher I. Measures, James W. Moffett, and Chris German

Subjects
010504 meteorology & atmospheric sciences, Geotraces, Ocean current, Global warming, Biogeochemistry, Climate change, Context (language use), Global change, 15. Life on land, 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, Oceanography, 13. Climate action, Geochemistry and Petrology, Environmental science, 14. Life underwater, World Ocean Circulation Experiment, 0105 earth and related environmental sciences
Abstract

Trace elements serve important roles as regulators of ocean processes including marine ecosystem dynamics and carbon cycling. The role of iron, for instance, is well known as a limiting micronutrient in the surface ocean. Several other trace elements also play crucial roles in ecosystem function and their supply therefore controls the structure, and possibly the productivity, of marine ecosystems. Understanding the biogeochemical cycling of these micronutrients requires knowledge of their diverse sources and sinks, as well as their transport and chemical form in the ocean. Much of what is known about past ocean conditions, and therefore about the processes driving global climate change, is derived from trace-element and isotope patterns recorded in marine deposits. Reading the geochemical information archived in marine sediments informs us about past changes in fundamental ocean conditions such as temperature, salinity, pH, carbon chemistry, ocean circulation and biological productivity. These records provide our principal source of information about the ocean's role in past climate change. Understanding this role offers unique insights into the future consequences of global change. The cycle of many trace elements and isotopes has been significantly impacted by human activity. Some of these are harmful to the natural and human environment due to their toxicity and/or radioactivity. Understanding the processes that control the transport and fate of these contaminants is an important aspect of protecting the ocean environment. Such understanding requires accurate knowledge of the natural biogeochemical cycling of these elements so that changes due to human activity can be put in context. Despite the recognised importance of understanding the geochemical cycles of trace elements and isotopes, limited knowledge of their sources and sinks in the ocean and the rates and mechanisms governing their internal cycling, constrains their application to illuminating the problems outlined above. Marine geochemists are poised to make significant progress in trace-element biogeochemistry. Advances in clean sampling protocols and analytical techniques provide unprecedented capability for high-density sampling and measurement of a wide range of trace elements and isotopes which can be combined with new modelling strategies that have evolved from the World Ocean Circulation Experiment (WOCE) and Joint Global Ocean Flux Study (JGOFS) programmes. A major new international research programme, GEOTRACES, has now been developed as a result of community input to study the global marine biogeochemical cycles of trace elements and their isotopes. Here, we describe this programme and its rationale

Published
2016

40. Apparent oxygen utilization rates calculated from tritium and helium-3 profiles at the Bermuda Atlantic Time-series Study site

Author

Rachel H. R. Stanley, Scott C. Doney, William J. Jenkins, and Dempsey E. Lott

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, lcsh:Life, Apparent oxygen utilisation, chemistry.chemical_element, Transit time, 01 natural sciences, Oxygen, lcsh:QH540-549.5, TRACER, Helium-3, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Earth-Surface Processes, Bermuda Atlantic Time-series Study, 010505 oceanography, 010604 marine biology & hydrobiology, lcsh:QE1-996.5, lcsh:Geology, lcsh:QH501-531, Oceanography, chemistry, 13. Climate action, Environmental science, Tritium, lcsh:Ecology, Thermocline
Abstract

We present three years of Apparent Oxygen Utilization Rates (AOUR) estimated from oxygen and tracer data collected over the ocean thermocline at monthly resolution between 2003 and 2006 at the Bermuda Atlantic Time-series Study (BATS) site. We estimate water ages by calculating a transit time distribution from tritium and helium-3 data. The vertically integrated AOUR over the upper 500 m, which is a regional estimate of export, during the three years is 3.1 ± 0.5 mol O2 m−2 yr−1. This is comparable to previous AOUR-based estimates of export production at the BATS site but is several times larger than export estimates derived from sediment traps or 234Th fluxes. We compare AOUR determined in this study to AOUR measured in the 1980s and show AOUR is significantly greater today than decades earlier because of changes in AOU, rather than changes in ventilation rates. The changes in AOU are likely a methodological artefact associated with problems with early oxygen measurements.

Published
2012

41. The geotraces intermediate data product 2014

Author

Edward Mawji, Andrew R. Bowie, François Lacan, Kenneth W. Bruland, Oliver J. Lechtenfeld, Laura F. Robinson, Martin Frank, Kuo-Fang Huang, Louise A. Zimmer, Loes J. A. Gerringa, Tobias Roeske, Jingfeng Wu, Célia Venchiarutti, Yanbin Lu, Géraldine Sarthou, Reiner Schlitzer, Tomas A. Remenyi, Yuichiro Kumamoto, Hein J W de Baar, Santiago R. Gonzalez, Mark J. Warner, Mak A. Saito, Peter N. Sedwick, Daniel C. Ohnemus, Evgenia Ryabenko, Emilie Grossteffan, Moritz Zieringer, William J. Jenkins, Gregory F. de Souza, Pinghe Cai, Martin Q. Fleisher, Johnny Stutsman, Yolanda Echegoyen-Sanz, Alessandro Tagliabue, Delphine Lannuzel, Mark Rehkämper, Abigail E. Noble, A. Radic, Lijuan Sha, Micha J. A. Rijkenberg, Mark A. Brzezinski, François Fripiat, Nicholas R. Bates, Toshitaka Gamo, Hisayuki Yoshikawa, Maija Heller, Alan M. Shiller, William M. Smethie, Joaquin E. Chaves, Elena Masferrer Dodas, Torben Stichel, Mark Rosenberg, Hai Cheng, Alicia Navidad, Patrick Laan, Peter Scott, Mark Baskaran, Stephen J.G. Galer, Frédéric Planchon, Jan van Ooijen, Huong Thi Dieu, Steven van Heuven, Feifei Deng, José Marcus Godoy, Catherine Jeandel, Xin Yuan Zheng, Frank Dehairs, Stephen R. Rintoul, Wafa Abouchami, R. Lawrence Edwards, Gideon M. Henderson, Eberhard Fahrbach, Yoshiki Sohrin, Tim M. Conway, Bronwyn Wake, Urumu Tsunogai, Evaline van Weerlee, Maeve C. Lohan, Katrin Bluhm, Robert F. Anderson, Eva Bucciarelli, Ken O. Buesseler, Marie Labatut, Peter Croot, Jana Friedrich, Christopher T. Hayes, Hendrik M. van Aken, James H. Swift, Seth G. John, Sven Kretschmer, Zichen Xue, Karel Bakker, Albert S. Colman, Pierre Branellec, Timothy C. Kenna, Benjamin S. Twining, Marie Boye, Alexander L. Thomas, Karen L. Casciotti, Jessica N. Fitzsimmons, Sabrina Speich, Jun Nishioka, Thomas M. Church, Mariko Hatta, Pere Masqué, Damien Cardinal, Charles R. McClain, Oliver Baars, Frederique le Moigne, Geoffrey J. Smith, Daniel M. Sigman, Edward A. Boyle, Ursula Schauer, Stephanie Owens, E. Malcolm S. Woodward, Maarten B Klunder, Lesley Salt, Gregory A. Cutter, Christopher I. Measures, Hajime Obata, Catherine Pradoux, Ester Garcia Solsona, James W. Moffett, Antje H L Voelker, Gabriel Dulaquais, Paul D. Quay, Saeed Roshan, Rob Middag, Johann Bown, Neil J. Wyatt, Phoebe J. Lam, Edward C.V. Butler, Michiel M Rutgers van der Loeff, Fanny Chever, Cyril Abadie, Viena Puigcorbé, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Department of Geosciences [Princeton], Princeton University, Institute for Environmental Research, Rheinisch-Westfälische Technische Hochschule Aachen (RWTH), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Antarctic Climate and Ecosystems Cooperative Research Centre (ACE-CRC), Institute for Marine and Antarctic Studies [Horbat] (IMAS), University of Tasmania [Hobart, Australia] (UTAS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), University of California, Marine Science Institute [Santa Barbara] (MSI), University of California [Santa Barbara] (UCSB), University of California-University of California, Woods Hole Oceanographic Institution (WHOI), Australian Institute of Marine Science (AIMS), State Key Laboratory of Marine Environmental Science (MEL), Xiamen University, Biogéochimie-Traceurs-Paléoclimat (BTP), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), NASA Goddard Space Flight Center (GSFC), Institute of Global Environmental Change [China] (IGEC), Xi'an Jiaotong University (Xjtu), Department of Earth Sciences [Minneapolis], University of Minnesota [Twin Cities] (UMN), University of Minnesota System-University of Minnesota System, Bonn University Hospital, College of Earth, Ocean, and Environment [Newark] (CEOE), University of Delaware [Newark], University College of London [London] (UCL), Department of Earth and Ocean Sciences [Columbia], University of South Carolina [Columbia], Old Dominion University [Norfolk] (ODU), Royal Netherlands Institute for Sea Research (NIOZ), Instituto de Química, Universidade de São Paulo, British Oceanographic Data Centre (BODC), National Oceanography Centre (NOC), Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], Massachusetts Institute of Technology (MIT), Universidad de Dakota del Sur, Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Bermuda Institute of Ocean Sciences (BIOS), Vrije Universiteit Brussel (VUB), Department of Mathematics and Science, National Taiwan Normal University (NTNU), GEOMAR LEGOS, Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Department of Chemistry, School of Life Sciences, University of Sussex, National Oceanography Centre [Southampton] (NOC), University of Southampton, Institut de Ciencia i Tecnologia Ambientals (ICTA), Universitat Autònoma de Barcelona (UAB), Oceans Institute and School of Physics, The University of Western Australia (UWA), School of Natural Sciences and Centre for Marine Ecosystems Research, Edith Cowan University, EDITH COWAN UNIVERSITY-EDITH COWAN UNIVERSITY, Department of Chemistry [Dunedin], University of Otago [Dunedin, Nouvelle-Zélande], Atmosphere and Ocean Research Institute [Kashiwa-shi] (AORI), The University of Tokyo (UTokyo), Bermuda Biological Station for Research (BBSR), Bermuda Biological Station for Research, Kyoto University [Kyoto], Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), SOEST, University of Hawai‘i [Mānoa] (UHM), FM-GEOMAR, Leibniz Institute of Marine Sciences at the University of Kiel, Department of Earth Ocean and Ecological Sciences [Liverpool], University of Liverpool, Bigelow Laboratory for Ocean Sciences, Department of Biology, Tufts University [Medford], RITE, Research Institute of Innovative Technology for the Earth, Royal Museum for Central Africa [Tervuren] (RMCA), IMT Lille Douai, Ecole nationale supérieure Mines-Télécom Lille Douai (IMT Lille Douai), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Analytical, Environmental and Geo- Chemistry, Chemistry, Analytical and Environmental Chemistry, Earth System Sciences, Analytical, Environmental & Geo-Chemistry, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), University of Tasmania (UTAS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD), University of Minnesota [Twin Cities], Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne] (LaMCoS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Universitat Autònoma de Barcelona [Barcelona] (UAB), The University of Tokyo, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Rheinisch-Westfälische Technische Hochschule Aachen University (RWTH), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute for Marine and Antarctic Studies [Hobart] (IMAS), University of California (UC), University of California [Santa Barbara] (UC Santa Barbara), University of California (UC)-University of California (UC), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), University Hospital Bonn, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), University of Sussex, Kyoto University, Laboratoire de physique des océans (LPO), Natural Environment Research Council (NERC), Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Boyle, Edward A, Fitzsimmons, Jessica Nicole, Echegoyen Sanz, Yolanda, Ocean Ecosystems, and Isotope Research

Subjects
Chemistry, Multidisciplinary, Geotraces, Digital data, trace elements, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Biology, Oceanography, ASCII, Isotopes, 0399 Other Chemical Sciences, Electronic atlas, GEOTRACES, Trace elements, 0402 Geochemistry, Environmental Chemistry, Bathymetry, 0405 Oceanography, 14. Life underwater, isotopes, Water Science and Technology, Stable isotopes, NetCDF, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Science & Technology, Information retrieval, ACL, General Chemistry, computer.file_format, Seawater samples, Ocean Data View, Metadata, Marine Sciences, Chemistry, electronic atlas, 13. Climate action, Data quality, Physical Sciences, geotraces, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, computer
Abstract

The GEOTRACES Intermediate Data Product 2014 (IDP2014) is the first publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2013. It consists of two parts: (1) a compilation of digital data for more than 200 trace elements and isotopes (TEIs) as well as classical hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing a strongly inter-linked on-line atlas including more than 300 section plots and 90 animated 3D scenes. The IDP2014 covers the Atlantic, Arctic, and Indian oceans, exhibiting highest data density in the Atlantic. The TEI data in the IDP2014 are quality controlled by careful assessment of intercalibration results and multi-laboratory data comparisons at cross-over stations. The digital data are provided in several formats, including ASCII spreadsheet, Excel spreadsheet, netCDF, and Ocean Data View collection. In addition to the actual data values the IDP2014 also contains data quality flags and 1-σ data error values where available. Quality flags and error values are useful for data filtering. Metadata about data originators, analytical methods and original publications related to the data are linked to the data in an easily accessible way. The eGEOTRACES Electronic Atlas is the visual representation of the IDP2014 data providing section plots and a new kind of animated 3D scenes. The basin-wide 3D scenes allow for viewing of data from many cruises at the same time, thereby providing quick overviews of large-scale tracer distributions. In addition, the 3D scenes provide geographical and bathymetric context that is crucial for the interpretation and assessment of observed tracer plumes, as well as for making inferences about controlling processes., National Science Foundation (U.S.) (OCE-0608600), National Science Foundation (U.S.) (OCE-0938349), National Science Foundation (U.S.) (OCE-1243377)

Published
2015

42. Hints and tricks

Author

Scott C. Doney, William J. Jenkins, and David M. Glover

Subjects
Case sensitivity, NetCDF, Programming language, Modelling methods, M-Files, Computer science, Computer graphics (images), Image tracing, computer.file_format, computer.software_genre, computer
Published
2011

43. Reconnaissance dating: A new radiocarbon method applied to assessing the temporal distribution of Southern Ocean deep-sea corals

Author

Andrea Burke, Laura F. Robinson, Kathryn M. Scanlon, Ann P. McNichol, William J. Jenkins, and Dana Gerlach

Subjects
Cnidaria, geography, geography.geographical_feature_category, biology, Continental shelf, Seamount, Aquatic Science, Oceanography, biology.organism_classification, Spatial distribution, Deep sea, law.invention, law, Radiometric dating, Radiocarbon dating, Coelenterata, Geology
Abstract

We have developed a rapid ‘reconnaissance’ method of preparing graphite for 14 C/ 12 C analysis. Carbonate (∼15 mg) is combusted using an elemental analyzer and the resulting CO 2 is converted to graphite using a sealed tube zinc reduction method. Over 85% ( n =45 replicates on twenty-one individual corals) of reconnaissance ages measured on corals ranging in age from 500 to 33,000 radiocarbon years (Ryr) are within two standard deviations of ages generated using standard hydrolysis methods on the same corals, and all reconnaissance ages are within 300 Ryr of the standard hydrolysis ages. Replicate measurements on three individual aragonitic corals yielded ages of 1076±35 Ryr (standard deviation; n =5), 10,739±47 Ryr ( n =8), and 40,146±3500 Ryr ( n =9). No systematic biases were found using different cleaning methods or variable sample sizes. Analysis of 13 C/ 12 C was made concurrently with the 14 C/ 12 C measurement to correct for natural fractionation and for fractionation during sample processing and analysis. This technique provides a new, rapid method for making accurate, percent-level 14 C/ 12 C analyses that may be used to establish the rates and chronology of earth system processes where survey-type modes of age estimation are desirable. For example, applications may include creation of sediment core-top maps, preliminary age models for sediment cores, and growth rate studies of marine organisms such as corals or mollusks. We applied the reconnaissance method to more than 100 solitary deep-sea corals collected in the Drake Passage in the Southern Ocean to investigate their temporal and spatial distribution. The corals used in this study are part of a larger sample set, and the subset that was dated was chosen based on species as opposed to preservation state, so as to exclude obvious temporal biases. Similar to studies in other regions, the distribution of deep-sea corals is not constant through time across the Drake Passage. Most of the corals from the Burdwood Bank (continental shelf of Argentina) have ages ranging between 0 and 2500 calendar years, whereas most of the corals from the Sars Seamount in the Drake Passage have ages between 10,000 and 12,500 calendar years. Such differences may be caused in part by sampling biases, but may also be caused by changes in larval transport, nutrient supply, or other environmental pressures.

Published
2010

44. A High-Performance 14C Accelerator Mass Spectrometry System

Author

Brad E. Rosenheim, K.F. von Reden, B.X. Han, Cameron McIntyre, E Galutschek, Ann P. McNichol, William J. Jenkins, Brett E. Longworth, Kathryn L. Elder, J. R. Burton, and Mark L. Roberts

Subjects
010506 paleontology, Archeology, 060102 archaeology, Chemistry, Nuclear engineering, Analytical chemistry, 06 humanities and the arts, 01 natural sciences, law.invention, law, General Earth and Planetary Sciences, 0601 history and archaeology, Radiocarbon dating, Beam (structure), 0105 earth and related environmental sciences, Accelerator mass spectrometry
Abstract

A new and unique radiocarbon accelerator mass spectrometry (AMS) facility has been constructed at the Woods Hole Oceanographic Institution. The defining characteristic of the new system is its large-gap optical elements that provide a larger-than-standard beam acceptance. Such a system is ideally suited for high-throughput, high-precision measurements of 14C. Details and performance of the new system are presented.

Published
2010

45. A Continuous-Flow Gas Chromatography 14C Accelerator Mass Spectrometry System

Author

Ernst Galutschek, Karl F. von Reden, Mark L. Roberts, Ann P. McNichol, Cameron McIntyre, and William J. Jenkins

Subjects
010506 paleontology, Archeology, Biodiesel, 060102 archaeology, Chemistry, Continuous flow, Sample (material), Analytical chemistry, 06 humanities and the arts, 01 natural sciences, Ion source, Ion, General Earth and Planetary Sciences, 0601 history and archaeology, Gas chromatography, Microwave, 0105 earth and related environmental sciences, Accelerator mass spectrometry
Abstract

Gas-accepting ion sources for radiocarbon accelerator mass spectrometry (AMS) have permitted the direct analysis of CO2 gas, eliminating the need to graphitize samples. As a result, a variety of analytical instruments can be interfaced to an AMS system, processing time is decreased, and smaller samples can be analyzed (albeit with lower precision). We have coupled a gas chromatograph to a compact 14C AMS system fitted with a microwave ion source for real-time compound-specific 14C analysis. As an initial test of the system, we have analyzed a sample of fatty acid methyl esters and biodiesel. Peak shape and memory was better then existing systems fitted with a hybrid ion source while precision was comparable. 14C/12C ratios of individual components at natural abundance levels were consistent with those determined by conventional methods. Continuing refinements to the ion source are expected to improve the performance and scope of the instrument.

Published
2010

46. The Passage of the Bomb Radiocarbon Pulse into the Pacific Ocean

Author

William J. Jenkins, Ann P. McNichol, Kathryn L. Elder, and Karl F. von Reden

Subjects
010506 paleontology, Archeology, Water mass, Antarctic Intermediate Water, 010504 meteorology & atmospheric sciences, Dissolved silica, North Atlantic Deep Water, 01 natural sciences, law.invention, Abyssal zone, Salinity, Oceanography, law, General Earth and Planetary Sciences, Radiocarbon dating, Thermocline, Geology, 0105 earth and related environmental sciences
Abstract

We report and compare radiocarbon observations made on 2 meridional oceanographic sections along 150°W in the South Pacific in 1991 and 2005. The distributions reflect the progressive penetration of nuclear weapons-produced 14C into the oceanic thermocline. The changes over the 14 yr between occupations are demonstrably large relative to any possible drift in our analytical standardization. The computed difference field based on the gridded data in the upper 1600 m of the section exhibits a significant decrease over time (approaching 40 to 50‰ in Δ14C) in the upper 200–300 m, consistent with the decadal post-bomb decline in atmospheric 14C levels. A strong positive anomaly (increase with time), centered on the low salinity core of the Antarctic Intermediate Water (AAIW), approaches 50–60‰ in Δ14C, a clear signature of the downstream evolution of the 14C transient in this water mass. We use this observation to estimate the transit time of AAIW from its “source region” in the southeast South Pacific and to compute the effective reservoir age of this water mass. The 2 sections show small but significant changes in the abyssal 14C distributions. Between 1991 and 2005, Δ14C has increased by 9‰ below 2000 m north of 55°S. This change is accompanied overall by a modest increase in salinity and dissolved oxygen, as well as a slight decrease in dissolved silica. Such changes are indicative of greater ventilation. Calculation of “phosphate star” also indicates that this may be due to a shift from the Southern Ocean toward North Atlantic Deep Water as the ventilation source of the abyssal South Pacific.

Published
2010

47. Gas ventilation of the Saguenay fjord by an energetic tidal front

Author

William J. Jenkins and Burkard Baschek

Subjects
Atmospheric Science, geography, geography.geographical_feature_category, Bubble, Noble gas, Fjord, Estuary, Oceanography, Sill, Environmental science, Aeration, Transect, Hydrography
Abstract

Dissolved noble gas samples were taken during a pilot study in the Saguenay Fjord, Quebec, Canada, in order to determine the contribution of different air‐sea gas exchange mechanisms in an estuary and to assess the contribution of tidal fronts to the aeration of subsurface waters. The noble gases He, Ne, Ar, Kr, and Xe span a large range of molecular diffusivities and solubilities and hence constitute a useful probe of various gas exchange and bubble injection processes. Samples were taken at flood tide upstream and downstream of an energetic tidal front that is generated by a hydraulically controlled flow over a shallow sill at the entrance to the Fjord. The results are interpreted with the help of hydrographic measurements of density and currents along cross‐sill transects describing the physical forcing at the sill. High gas saturations downstream of the sill indicate the aeration of water within the frontal region. An inverse model is used to compare the contribution of bubble injection in th...

Published
2009

48. The distributions of, and relationship between, 3He and nitrate in eddies

Author

Dennis J. McGillicuddy, D.E. Lott, and William J. Jenkins

Subjects
chemistry.chemical_compound, Oceanography, Nitrate, chemistry, Eddy, Anticyclone, Aphotic zone, Environmental science, Upwelling, Photic zone, New production, Thermocline
Abstract

We present and discuss the distribution of 3 He and its relationship to nutrients in two eddies (cyclone C1 and anticyclone A4) with a view towards examining eddy-related mechanisms whereby nutrients are transported from the upper 200–300 m into the euphotic zone of the Sargasso Sea. The different behavior of these tracers in the euphotic zone results in changes in their distributions and relationships that may provide important clues as to the nature of physical and biological processes involved. The cyclonic eddy (C1) is characterized by substantial 3 He excesses within the euphotic zone. The distribution of this excess 3 He is strongly suggestive of both past and recent ongoing deep-water injection into the euphotic zone. Crude mass balance calculations suggest that an average of approximately 1.4±0.7 mol m −2 of nitrate has been introduced into the euphotic zone of eddy C1, consistent with the integrated apparent oxygen utilization anomaly in the aphotic zone below. The 3 He–NO 3 relationship within the eddy deviates substantially from the linear thermocline trend, suggestive of incomplete drawdown of nutrients and/or substantial mixing between euphotic and aphotic zone waters. Anticyclone (A4) displays a simpler 3 He–NO 3 relationship, but is relatively impoverished in euphotic zone excess 3 He. We suggest that because of the relatively strong upwelling and lateral divergence of water the residence time of upwelled 3 He is relatively short within the euphotic zone of this eddy. An estimate of the recently upwelled nutrient inventory, based on the excess 3 He observed in A4's lower euphotic zone, is stoichiometrically consistent with the oxygen maximum observed in the euphotic zone.

Published
2008

49. Software development for continuous-gas-flow AMS

Author

Robert J. Schneider, K.F. von Reden, Mark L. Roberts, Ann P. McNichol, Brad E. Rosenheim, and William J. Jenkins

Subjects
Nuclear and High Energy Physics, Signal processing, Computer simulation, business.industry, Computer science, Software development, Data acquisition, Software, Synchronization (computer science), business, Instrumentation, Computer hardware, Computer Automated Measurement and Control, Accelerator mass spectrometry
Abstract

The National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility at Woods Hole Oceanographic Institution is presently completing installation of a novel continuous-flow AMS system. A multi-year development of an AMS microwave gas ion source in collaboration with Atomic Energy Canada Limited (AECL), Chalk River, has preceded this final step of an implementation that is expected to add a new dimension to 14C AMS. National Instruments, NIM, and CAMAC modules have been programmed with LabVIEW on a Windows XP platform to form the basis for data acquisition. In this paper we discuss possible applications and include simulations of expected data acquisition scenarios like real-time AMS analysis of chromatograms. Particular attention will have to be given to issues of synchronization between rapidly changing input amplitudes and signal processing cycles in hardware and software.

Published
2008

50. The biogeochemical consequences of changing ventilation in the Japan/East Sea

Author

William J. Jenkins

Subjects
Water mass, geography, geography.geographical_feature_category, Global warming, Pelagic zone, General Chemistry, New production, Oceanography, Abyssal zone, Water column, Sea ice, Environmental Chemistry, Photic zone, Geology, Water Science and Technology
Abstract

Transient tracer observations in the Japan/East Sea are used in combination with a minimum complexity water mass model to successfully constrain the timing, nature and magnitude of recent changes in its ventilation. The data and model indicate that there has been a nearly 10-fold decrease in deep water formation rates since during the early 1960s, marked by a transition from sea ice/brine-rejection based deep water mass formation to a shallower open ocean convective renewal. The ventilation rates thus computed allow the calculation of the regional scale flux of phosphate from the abyss to the euphotic zone, and hence basin-scale new production. In addition, water column remineralization rates for phosphate and oxygen utilization rates show expected and consistent patterns as a function of depth. The reduction in abyssal ventilation of the Japan/East Sea (JES) during the latter half of the 20th century led to a 2-fold decrease in basin-scale new production. This decrease has significant implications for the strength and resilience of the marine food web in a strategically important marginal sea. The change appears consistent with trends in zooplankton biomass estimates in the western JES, and possibly with changes in the character of fish-catches. Recent observations made by others indicate a significant resurgence of brine-rejection related deep water formation during the winter of 2001, but it remains to be seen whether this will be sustained in the face of global warming trends.

Published
2008

Catalog

Books, media, physical & digital resources
See catalog results