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This study describes the research-to-operations process leading to a recent change in tropical cyclone (TC) reconnaissance sampling patterns as well as observing-system experiments that evaluated the impact of that change on numerical weather prediction model forecasts of TCs. A valuable part of this effort was having close, multipronged connections between the TC research and operational TC prediction communities at the National Oceanic and Atmospheric Administration (NOAA). Related to this work, NOAA's Atlantic Oceanographic and Meteorological Laboratory (AOML) and National Hurricane Center (NHC) have a long history of close collaboration to improve TC reconnaissance. Similar connections between AOML and NOAA's Environmental Modeling Center (EMC) also laid a foundation for the observing-system experiments conducted here. More specifically, AOML and NHC collaborated in 2018 to change how NHC uses NOAA's Gulfstream-IV (G-IV) jet during TC synoptic surveillance missions. That change added a second circumnavigation at approximately 1.5° from TC centers, when possible. Preliminary experiments suggest that the change improved track forecasts, though the intensity results are more mixed. Despite the somewhat small sample size over a 3-yr period, the track improvement does agree with prior work. This effort has led to additional work to more fully examine G-IV sampling strategies. [ABSTRACT FROM AUTHOR]

The chemistry of the global ocean is rapidly changing due to the uptake of anthropogenic carbon dioxide (CO2). This process, commonly referred to as ocean acidification (OA), is negatively impacting many marine species and ecosystems. In this study, we combine observations in the global surface ocean collected by NOAA Pacific Marine Environmental Laboratory and Atlantic Oceanographic and Meteorological Laboratory scientists and their national and international colleagues over the last several decades, along with model outputs, to provide a high-resolution, regionally varying view of global surface ocean carbon dioxide fugacity, carbonate ion content, total hydrogen ion content, pH on total scale, and aragonite and calcite saturation states on selected time intervals from 1961 to 2020. We discuss the major roles played by air-sea anthropogenic CO2 uptake, warming, local upwelling processes, and declining buffer capacity in controlling the spatial and temporal variability of these parameters. These changes are occurring rapidly in regions that would normally be considered OA refugia, thus threatening the protection that these regions provide for stocks of sensitive species and increasing the potential for expanding biological impacts. [ABSTRACT FROM AUTHOR]

Since 2017, NTNU's Applied Underwater Robotics Laboratory has been developing an infrastructure for remote marine/subsea operations in Trondheim Fjord. The infrastructure, named the OceanLab subsea node, allows remote experimentation for three groups of assets: seabed infrastructure, surface or subsea vehicles/robots, and assets at remote experimentation sites. To achieve this task, a shoreside control room serves as a hub that enables efficient and diverse communication with assets in the field as well as with remote participants/operators. Remote experimentation has become more popular in recent years due to technological developments and convenience, the COVID-19 pandemic, and travel restrictions that were imposed. This situation has shown us that physical presence at the experimentation site is not necessarily the only option. Sharing of the infrastructure among different experts, which are geographically distributed, but participating in a single, local, real-time experiment, increases the level of expertise available and the efficiency of the operations. This paper also elaborates on the development of a virtual experimentation environment that includes simulators and digital twins of various marine vehicles, infrastructures, and the operational marine environment. By leveraging remote and virtual experimentation technologies, users and experts can achieve relevant results in a shorter time frame and at a reduced cost. [ABSTRACT FROM AUTHOR]

Internal solitary waves are commonly present in global oceans, and these waves encounter submarine ridges during their propagation, resulting in breaking. In this study, a two-layer fluid model and the gravity collapsing method were used to simulate the breaking process of internal solitary waves encountering submarine ridges in the laboratory, and particle image velocimetry was used to monitor the flow field. Based on the different roles of motion mechanisms in the wave-breaking process, the breaking types were classified. Moreover, the relationship between the topography, the initial parameters of internal solitary waves, and the breaking types was studied, and the movement parameters during the wave-breaking process were analyzed. The experiments showed that the Iribarren number and Bisw parameter proposed based on the gentle slope breaking process could not effectively classify the breaking types when internal solitary waves encountered submarine ridges because the permeability of the submarine ridges was different from that of gentle slopes, which significantly affected the motion mechanism during the breaking process. The movement parameter γ clearly reflected the roles of different motion mechanisms during the wave-breaking process. Another parameter δ established the relationship between the motion mechanisms and the topography and initial wave parameters. [ABSTRACT FROM AUTHOR]

Copyright of BSGF: Earth Sciences Bulletin is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This review of French research on fisheries in the Northwest Atlantic first summarizes the history of the access rights of the French fleets to the fishing grounds of this area, then the evolution of the fisheries management systems. The focus then shifts toward French fishery research from the beginning of the 20th century. Four major periods are described to characterize the objectives of this research, its implementation, and its results. The first French scientific studies of fisheries in the Davis Strait, Newfoundland, and Nova Scotia banks by fishery support vessels date back to the 19th century. These studies intensified from the middle of the 20th century with the deployment of dedicated research vessels, especially from 1970 with the establishment of a research laboratory and an oceanographic vessel in Saint-Pierre and Miquelon (SPM). These assets, a close collaboration with laboratories in Canada and the United States, and participation in the work of the regional fisheries commission (ICNAF/NAFO) enabled the teams in SPM to develop and perform innovative research. However, the delimitation in 1992 of the EEZ in Canada and around SPM and the depletion of the main fish stocks dealt a severe blow to the French fisheries in this region, causing France to review its research strategy. [ABSTRACT FROM AUTHOR]

Complexities of acoustic propagation in ducts have long been known, e.g., shallow water environments and deep waters off Gibraltar. The "Beaufort Lens" (Lens) is a duct north of Alaska with nominal depths between 60 and 200 m and is reachable by oceanographic instruments and underwater unmanned vehicles and submarines. Propagation within the ducts is governed by waveguide physics. The frequencies must be high enough to support the modes within them such that there is a "critical frequency" (CF) where modes start to "detach" from surface loss mechanisms. Therefore, transmission losses (TLs) can abruptly decrease once a mode "fits" within a duct. This paper describes an experimental part of Ice Exercise 2018 supported by the U.S. Navy's Arctic Submarine Laboratory. The signals were transmitted from Camp Sargo north of Prudhoe Bay to the submarines SSN Hartford, SSN Connecticut, and HMS Trenchant. The data indicate low TLs near 100 Hz and an abrupt 10 dB decrease in TLs 244–280 Hz, both suggesting CFs. Modeling suggests CFs for modes 1 near 100 Hz and a higher CF when modes 3–6 "cascade" into the Lens starting near 250 Hz. There are also abrupt increases in TLs at other frequencies, which are explained by nulls in the product of the mode functions. [ABSTRACT FROM AUTHOR]

• Processing of three different kinds of drifters to extract the geostrophic component. • The use of drifters leads to a higher improvement than an additional altimeter. • Improvement is of 1% in SLA and 10% in meridional velocities. • Both components of the velocity vector have similar accuracy. Knowledge of ocean surface geostrophic circulation has been greatly improved due to satellite observations. However, it is essential to use different observation sources (satellites and in situ data) in order to improve accuracy and resolution. This study combines along-track Sea Level Anomalies (SLA) with geostrophic velocity estimated from surface drifters to map SLA and associated geostrophic current anomalies in the Gulf of Mexico. Firstly, substantial pre-processing is needed on the drifter data to extract the geostrophic component of the signal in order to be consistent with the physical content provided by altimetry. This step includes estimating and removing the Ekman current, Stokes drift and wind slippage. Three kinds of drifters are used: – Drifters belonging to Woods Hole Group, a CLS Group company that launches their own drifters in the Gulf of Mexico. – Drifters launched in the framework of the Lagrangian Submesoscale ExpeRiment (LASER) campaign (January-April 2016). – Drifters from Atlantic Oceanographic and Meteorological Laboratory (AOML). Secondly, drifters and along-track SLA from Jason2, HY2, SARAL and Cryosat-2 are combined through multivariate objective analysis to map a daily time series of SLA and associated geostrophic current anomalies from 01/09/2015 to 30/04/2016. Finally, comparisons with independent data reveal the improved agreement of maps combining both altimetry and drifter data, especially for the meridional component of geostrophic current. [ABSTRACT FROM AUTHOR]

A region of exceptionally high macrofaunal benthic biomass exists in Barrow Canyon, implying a carbon export process that is locally concentrated. Here we offer an explanation for this benthic "hotspot" using shipboard data together with a set of dynamical equations. Repeat occupations of the Distributed Biological Observatory transect in Barrow Canyon reveal that when the northward flow is strong and the density front in the canyon is sharp, plumes of fluorescence and oxygen extend from the pycnocline to the seafloor in the vicinity of the hotspot. By solving the quasi‐geostrophic omega equation with an analytical flow field fashioned after the observations, we diagnose the vertical velocity in the canyon. This reveals that, as the along stream flow converges into the canyon, it drives a secondary circulation cell with strong downwelling on the cyclonic side of the northward flow. The downwelling quickly advects material from the pycnocline to the seafloor in a vertical plume analogous to those seen in the observations. The plume occurs only when the phytoplankton reside in the pycnocline, since the near‐surface vertical velocity is weak, also consistent with the observations. Using a wind‐based proxy to represent the strength of the northward flow and hence the pumping, in conjunction with a satellite‐derived phytoplankton source function, we construct a time series of carbon supply to the bottom of Barrow Canyon. Plain Language Summary: In this study, we use shipboard occupations of a transect across Barrow Canyon in the northeast Chukchi Sea, together with a set of dynamical equations, to explain why exceptionally large concentrations of macrofauna are found on the seafloor there. The observations reveal that when the northward flow through the canyon is strong and a sharp cross‐canyon density contrast is present, plumes of phytoplankton extend from the middle of the water column to the seafloor in the vicinity of this benthic "hotspot." Using an idealized representation of the canyon flow, we solve the equations for the vertical velocity. This reveals that, as the northward flow accelerates through the canyon, strong downward velocities quickly transfer the phytoplankton to the bottom—in line with the observations. Since the strength of the current depends on the wind, we develop a proxy for the pumping using a nearby wind record. Using satellite data, we also construct a record of the amount of phytoplankton entering the canyon. Together, this provides an estimate of the food supply to the bottom of Barrow Canyon. Key Points: Shipboard transects across Barrow Canyon reveal vertical plumes of fluorescence and oxygen extending to the bottom when the flow is strongSolution of the quasi‐geostrophic omega equation reveals that downwelling on the cyclonic side of the current drives the plumesThis source of carbon to the seafloor can explain the enhanced levels of macrofaunal benthic biomass in the center of Barrow Canyon [ABSTRACT FROM AUTHOR]

This study describes biweekly (defined as periods between 10 and 15 days) ocean variability in relation to equatorial wave theory using a comprehensive set of moored ocean current velocities as well as satellite‐retrieved oceanic and atmospheric parameters in the Indian Ocean. Moored biweekly current velocities exhibit the meridional structure of mixed Rossby‐gravity waves: Symmetric for meridional velocity and antisymmetric for zonal velocity around the equator with a decay scale of 228–309 km. The biweekly meridional velocity along the equator has average zonal and vertical wavelengths of 3,430 ± 550 km and 0.76 ± 0.15 km, respectively, with phase propagating westward at speeds of 2.8–3.1 m s−1 and upward at 54–56 m day−1. Conversely, wave energy is inferred to propagate eastward and downward. The range of best fit constants (1.4–2.0 m s−1) that result from the linear separation of horizontal and vertical wave structures suggests the second baroclinic wave mode is dominant over other low baroclinic modes in accounting for the velocity variability. The biweekly waves are forced by surface winds; satellite‐derived wind stress, sea level, and surface current anomalies, regressed against the first principal component of the biweekly moored velocities, illustrate the basin‐scale structure and temporal evolution of the waves. Plain Language Summary: An extensive set of moored ocean current velocities permits evaluation of the three‐dimensional flow field properties, dynamics, and energetics of biweekly waves in the Indian Ocean. We determine, for the first time, the meridional structure of the biweekly flow field from the multiyear in situ measurements and demonstrate that it is dynamically consistent with that of Rossby‐gravity waves, with zonal velocity being antisymmetric and meridional velocity being symmetric about the equator. Our analysis finds that the waves have a decay scale of 228–309 km away from the equator in the meridional direction, a zonal wavelength of 3,430 ± 550 km, and vertical wavelength of 0.76 ± 0.15 km. Phase propagates westward at speeds of 2.8–3.1 m s−1 and upward at 54–56 m day−1, while wave energy flux is eastward and downward. A combination of moored velocities and satellite‐derived data illustrates the basin‐scale structure and temporal evolution of the waves in the Indian Ocean. Key Points: Biweekly variations are prominent in moored buoy velocity and satellite sea level measurements in the equatorial Indian OceanThe properties of these biweekly oscillations are consistent with wind‐forced mixed Rossby‐gravity wavesPhase propagation of the biweekly Rossby‐gravity waves is westward and upward while energy propagation is eastward and downward [ABSTRACT FROM AUTHOR]

Summary: The article presents the results of new underwater and laboratory investigations carried out on a cargo of columns and blocks of Roman age from a shipwreck sunk off Capo Taormina (Sicily). The archaeometric analyses (powder XRD and OM with thin sections) indicate the use of marmor luculleum (africano) from the ancient Ionian town of Teos for the columns. The authors compare their results with the data obtained from the other two shipwrecks carrying the same marble sunk off the southern coast of France (Dramont I and Chrétienne M) together with abrasive materials (pumice and corundite [emery]), applying the relevant archaeometric analyses. A maritime traffic of the prestigious stone from Teos into the Central Mediterranean, combined with pumice (from Lipari?) and Naxian corundite – both used in the working of marble ‐ is here reconstructed for the first time. We also propose a date for the Taormina cargo. [ABSTRACT FROM AUTHOR]

The article presents information on temporary rainfall history in the southeast of the Peninsula from September 11 to 15, 2019. It notes that the extraordinary rainfall registers, which exceeded 300 mm, arrived to be an absolute record of precipitation in a day at observatories with long series like Alcantarilla, Murcia, Cartagena, Orihuela and Ontinyent, among others with shorter series of data. It adds that the zones most affected were large areas of the Valencian Community.

Regular biological observations of the deep sea bottom fauna are very important for understanding the role benthic biota plays in ocean ecosystems. Temporal variability in macrobenthos structure is usually studied in terms of general community characteristics including density, biomass and diversity. In this investigation, we also focused on the species composition and their individual characteristics in terms of temporal dynamics. The deep-sea macrofauna was studied based on the material collected in the Eastern Fram Strait during two expeditions in July-August 2003 and July 2012. Stations were taken at depths of about 2500 m at the deep-sea observatory using the USNEL box corer (0.25 m2). Three stations at varying distances were sampled in 2003 (three cores per station). In 2012, the same stations were resampled with an additional station taken close to the central HAUSGARTEN permanent sampling site (one core per station). No significant changes in the total density and biomass were found between the two sampling events. However, the density of several common species has changed significantly (e.g. densities of Mendicula ockelmanni and Chaetozone cf. jubata have increased). Four species out of total 64 were unique for the 2003 samples, while six species out of 52 were unique for 2012 samples. The absence of several particular species in the samples from the different years is estimated to be not random: the number of samples required to find these species was less than the number of samples collected. The differences in time between the very same stations exceeded the inner spatial heterogeneity of each of the three stations. However, the spatial heterogeneity within the scale of 20-25 km exceeded the temporal differences. [ABSTRACT FROM AUTHOR]

The article discusses the Tektite ocean exploration project of the U.S. government. The project emerged from a space simulation study performed by General Electric Co. and was named after a mysterious object found at the bed of the ocean. It was started to examine the capability of a group of men in executing extensive scientific mission while living in a dry habitat on the ocean floor for a long period of time. The objective of the study is to emphasize marine scientific, behavioral and biomedical programs, and it positioned the underground work for the elaboration of undersea procedures to be conducted.

Sea level anomalies (SLAs) derived from satellite observations (over a period of 22 years) and tide gauge data compiled from 66 stations from the eastern Indian Ocean and South China Sea (SCS) and western Pacific Ocean have been analyzed to study the interannual to long term variation of SLAs in the eastern Indian Ocean and SCS. Spatial patterns of sea level variability on the eastern boundary of the Indian Ocean exhibit non-coherent variability with SCS but show coherent variability with western Pacific Ocean. We find coherent variability in interannual SLAs in the Bay of Bengal, Andaman Sea, Malacca Strait and Java Strait. A large fraction of interannual SLA variations in the eastern SCS and interior SCS is linked to El Niño-Southern Oscillation (ENSO) and rest of the region is characterized by small scale interannual variations. The interannual SLAs in the SCS show seasonality with pronounced variation during winter and fall seasons. Interannual surface wind anomalies associated with Indian Ocean Dipole (IOD) and ENSO explain sea level interannual variability in the eastern Indian Ocean and SCS. The decadal sea level variability associated with Pacific Decadal Oscillation (PDO) and decadal ENSO are observed in the SCS. [ABSTRACT FROM AUTHOR]

Utö Atmospheric and Marine Research Station is located on Utö Island (59°46'50 N, 21°22'23 E) at the outer edge of the Archipelago Sea, Baltic Sea towards the Baltic Sea Proper. Meteorological observations at the island started in 1881 and vertical profiling of sea water temperature and salinity in 1900. In this study, we analyze long-term changes of atmospheric temperature, cloudiness and sea salinity, temperature and ice cover. Our main dataset consists of 248 367 atmospheric temperature observations, 1632 quality assured vertical seawater temperature and salinity profiles and 8565 ice maps, partly digitized for this project. We also use North Atlantic Oscillation (NAO) and Major Baltic Inflow (MBI) data from the literature as reference variables to our data. Our analysis is based on statistical method utilizing dynamic linear model. The results show an increase in the atmospheric temperature at Utö, but the increase is significantly smaller than on land areas and takes place only since early 1980's, with a rate of 0.4 °C/decade during the last 35 years. We also see an increase on sea water temperatures, especially on the surface, with an increase of 0.3 °C/decade for the last 100 years. In deeper water layers the increase is smaller and influenced by vertical mixing, which is modulated by inflow of saline water from the North Sea and fresh water inflow. Date when air temperature in the spring exceeds +5 °C has become 5 days earlier from the period 1951-1980 to period 1981-2010 and date when sea surface water temperature exceed +4 °C has changed 9 days earlier. Sea ice cover duration at Utö shows a decrease of approximately 50 % during the last 35 years. Based on the combined results, it is possible that the climate at Utö may have changed into a new phase, in which ice do not reduce the local effects of global temperature increase. [ABSTRACT FROM AUTHOR]

Copyright of Hydrographic Surveying & Charting / Haiyang Cehui is the property of Hydrographic Surveying & Charting Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the late 19th century, there was a bloom of public aquariums throughout Europe. Some of them were built for entertainment purposes, whereas others were connected to marine science stations. This article explores the origins and development of the aquarium/marine research station Vasco da Gama (Portugal) as an example of this duality. Initially, the aquarium was created in 1898 by the Portuguese Society of Geography, in a political context of national affirmation. In the first years, a deficient establishment, lack of financial resources, and scarce technical knowledge contributed for its degradation. Therefore, the Navy took over the aquarium in the early 1900s, delivering its management some years later to the Portuguese Society of Natural Sciences. After improvements and modifications, it became one of the first marine biological stations in 1919. This was important for the development of national marine science research at a time of scarce resources. Despite many years of a symbiotic relation between science research and dissemination, the demolition of part of the aquarium/marine station due to a road construction in 1940 brought issues of disequilibrium between both functions. This eventually led to the separation of aquarium and marine station in 1950. Other themes such as connections to national and international institutions are also discussed. [ABSTRACT FROM AUTHOR]

Four cruises were conducted in Jiaozhou Bay from January to November in 2008 to study carbon monoxide (CO) distribution, diurnal variation, seasonal variation, and sea-to-air flux. Surface water CO concentration exhibited strong diurnal variations at an anchor station in both April and November, with highest CO concentration 3–5 times higher than minimum values. Diurnal variation (sampling time) exerts an overall pattern on CO distribution, spatially distributed factors impose extra influence. High CO concentrations and fluxes were observed in the eastern, northern, and western parts of the bay, which are close to areas of estuaries, dense population, and high industrialization, reflecting the impact of human activities on CO distribution. Both surface water CO concentrations and sea-to-air fluxes showed seasonal variations, with the highest values in summer and the lowest values in winter. Sea-to-air CO flux in Jiaozhou Bay ranged from 0 to 34.66 μmol m − 2 d − 1 with a mean flux of 4.96 μmol m − 2 d − 1 . [ABSTRACT FROM AUTHOR]

This compilation presents a historical synthesis of the studies carried out (publications, thesis, monogrphs) on the zooplankton in the Bay of Mochima, Sucre State, Venezuela. The Plankton Laboratory of the Institute of Zoology and Tropical Ecology (IZET) and the Zooplankton Laboratory of the Venezuelan Oceanographic Institute (IOV) have carried out numerous studies of the zooplankton community, in which they emphasize taxonomic and ecological aspects including the effects of upwelling events. Among these, the level of information is very uneven. A list of zooplankton composition and richness is presented. The holoplankton components include jellyfish (19 species), siphonophores (5 species), copepods (75 species), cladocerans (4 species), chaetognatha (3 species), holoplanktonic mollusks (2 species), mysidacea (2 species), appendicularians (16 species). Within the meroplankton are larvae of decapod crustaceans, cirripedes and ichthyoplankton. In general, copepods were the most abundant group, with differences in upwelling events and represented the highest proportion of biomass. Temporal and spatial biomass fluctuations, zooplankton abundance and related physical and chemical variables were analyzed. However, the variables needed to estimate production, such as annual cycles and trophic relationships, have been poorly studied. Depending on the lack of information, the main problems were identified and recommendations for future research are proposed. [ABSTRACT FROM AUTHOR]

The hull–propeller interaction of autonomous underwater vehicle (AUV) in straight and oblique flow is numerically studied. The study is performed based on computational fluid dynamics (CFD) and the general commercial software ANSYS Workbench. The multiple reference frames (MRF) method and the shear stress transport (SST) k − ω turbulence model are adopted. Firstly, the drag of Suboff AUV and the open water performance of the Wageningen B-3-50 propeller are simulated numerically. The errors are all within 5%, validating the reliability of the method in this paper. Then, the Sailfish AUV and B-3-35 propeller developed by the Underwater Vehicle Laboratory (UVL) of Ocean University of China are simulated. The maximum incremental drag produced by the appendages reaches even more than 1.5 times the hull drag. Propeller rotation causes an additional hull drag increment of over 25%. With an inlet velocity of 1.5 m/s, the thrust and torque behind the bare hull increase by 16.7% and 6.4%, respectively. The effect of angle of attack on drag is more significant at high velocity. Finally, the numerical simulation result 1.825 m/s and experimental result 1.75 m/s are compared. This study has implications for guidance on AUV integration analysis. • The hull–propeller interaction of autonomous underwater vehicle in straight and oblique flow is numerically studied. • The wake changes the propulsion performance of the propeller while the propeller modifies the pressure distribution. • The self-propulsion point is predicted, and the wake fraction and thrust deduction factor are calculated. • The appendages seriously affect the flow distribution around the hull, and quantitative conclusions are given. [ABSTRACT FROM AUTHOR]

Water transparency is a primary indicator of optical water quality that is driven by suspended particulate and dissolved material. A data set from the operational Time Series Station Spiekeroog located at a tidal inlet of the Wadden Sea was used to perform (i) an inter-comparison of observations related to water transparency, (ii) correlation tests among these measured parameters, and (iii) to explore the utility of both acoustic and optical tools in monitoring water transparency. An Acoustic Doppler Current Profiler was used to derive the backscatter signal in the water column. Optical observations were collected using above-water hyperspectral radiometers and a submerged turbidity metre. Bio-fouling on the turbidity sensors optical windows resulted in measurement drift and abnormal values during quality control steps. We observed significant correlations between turbidity collected by the submerged metre and that derived from abovewater radiometer observations. Turbidity from these sensors was also associated with the backscatter signal derived from the acoustic measurements. These findings suggest that both optical and acoustic measurements can be reasonable proxies of water transparency with the potential to mitigate gaps and increase data quality in long-time observation of marine environments. [ABSTRACT FROM AUTHOR]

Intercomparison of trace metal data is a key aspect of the International GEOTRACES program, allowing data from multiple laboratories and countries to be combined to produce high-resolution datasets for the oceans. The use of crossover stations by the GEOTRACES program provides the opportunity both for comparison of analytical techniques and assessment of temporal variability in the cycling of trace metals such as iron (Fe). Here, we present the first comparison of dissolved Fe stable isotope ratio (δ 56 Fe; relative to IRMM-014) profiles in the oceans, from reoccupations of three locations in the Atlantic Ocean; (1) the Bermuda Atlantic Time Series station (31.75°N 64.17°W) during the US GEOTRACES IC1 cruise (June 2008) and the US GEOTRACES GA03 cruise (Nov. 2011); (2) the Tenatso Time Series station near Cape Verde (17.4°N 24.5°W) during the U.S GEOTRACES GA03 cruises (2010; 2011), and (3) a station in the Cape Basin close to South West Africa (31.1–31.4°S 36.5°W) during the French GEOTRACES GIPY4 Bonus Good Hope Cruise (Feb. 2008) and the UK GEOTRACES GA10 D357 cruise (Oct. 2010). These datasets provided us with the opportunity not only to compare sampling and analysis techniques by two different laboratories (USC and LEGOS), but also the temporal variability of δ 56 Fe at these locations on a 1–3 year timescale. We found that a good agreement between data and profiles generated by different laboratories does allow assessment of temporal variation of δ 56 Fe in the water column, as well as spatial variability and synthesis of datasets from different regions of the ocean. In fact, comparison of δ 56 Fe at the three locations in this study demonstrates a remarkable consistency between the shapes of ocean δ 56 Fe profiles measured 1–3 years apart, pointing to the overall stability of Fe cycling at all three locations on these timescales, despite the expected dynamic nature of the Fe cycle. This consistency is highlighted by strong agreement in δ 56 Fe throughout the whole water-column at Bermuda, and in waters deeper than 500 m in the Cape Basin, which suggests that different water masses may carry distinct δ 56 Fe signatures. In contrast to these stable δ 56 Fe, we did observe apparent temporal variability in δ 56 Fe between cruises at other locations and in surface waters, both throughout the water column at Cape Verde, and in Agulhas-leakage influenced surface waters in the Cape Basin. Such temporal variability may thus provide information about changes in internal Fe cycling or external Fe sources on these timescales. Overall, this study highlights the usefulness of repeat δ 56 Fe measurements to provide information on the variability of Fe cycling throughout the oceans. [ABSTRACT FROM AUTHOR]

Most oceanographic instruments on the seafloor have no connections with the surface and therefore have to run on batteries and store data until recovery. To demonstrate a developing technology, sensors and acoustic modems were powered with energy harvested from the seafloor, and data were relayed acoustically in near-real time to the Monterey Accelerated Research System (MARS) observatory in Monterey Bay, California, and to surface research vessels. MARS is a cabled observatory in deep water (~890 m) at the edge of Monterey Canyon. An acoustic modem was attached to the MARS node and configured to send out commands to, and relay data received from, remote modems. Two benthic microbial fuel cells (BMFCs) positioned approximately 0.5 km away from MARS supplied power to the remote modems and sensors. At their peak performance, these BMFCs produced continuous power densities of ~35 mW m−2 (footprint area). The modems utilized in this study contained an integrated power management platform (PMP) designed to manage and store the electrical energy generated by each BMFC and to record BMFC performance parameters and sensor data on an hourly basis. Temperature and either oxygen or conductivity sensors were chosen because of their common use and environmental relevance. Acoustically transmitted data records show that the BMFCs renewed energy stores and that the oceanographic sensors measured dissolved oxygen, temperature, and conductivity reliably throughout the operational life of each BMFC system (~6 months). These systems remained in place for more than 12 months. [ABSTRACT FROM AUTHOR]