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103. Near‐Surface Stratification Due to Ice Melt Biases Arctic Air‐Sea CO2 Flux Estimates.

Author

Dong, Yuanxu, Yang, Mingxi, Bakker, Dorothee C. E., Liss, Peter S., Kitidis, Vassilis, Brown, Ian, Chierici, Melissa, Fransson, Agneta, and Bell, Thomas G.

Subjects
ATMOSPHERIC carbon dioxide, MELTWATER, EDDY flux, SEA ice, CARBON dioxide, MELTING
Abstract

Air‐sea carbon dioxide (CO2) flux is generally estimated by the bulk method using upper ocean CO2 fugacity measurements. In the summertime Arctic, sea‐ice melt results in stratification within the upper ocean (top ∼10 m), which can bias bulk CO2 flux estimates when the seawater CO2 fugacity is taken from a ship's seawater inlet at ∼6 m depth (fCO2w_bulk). Direct flux measurements by eddy covariance are unaffected by near‐surface stratification. We use eddy covariance CO2 flux measurements to infer sea surface CO2 fugacity (fCO2w_surface) in the Arctic Ocean. In sea‐ice melt regions, fCO2w_surface values are consistently lower than fCO2w_bulk by an average of 39 μatm. Lower fCO2w_surface can be partially accounted for by fresher (≥27%) and colder (17%) melt waters. A back‐of‐the‐envelope calculation shows that neglecting the summertime sea‐ice melt could lead to a 6%–17% underestimate of the annual Arctic Ocean CO2 uptake. Plain Language Summary: The Arctic Ocean is considered to be a strong sink for atmospheric CO2. The air‐sea CO2 flux is almost always estimated indirectly using bulk seawater CO2 fugacity measured from the ship's seawater inlet at typically ∼6 m depth. However, sea‐ice melt results in near‐surface stratification and can cause a bias in air‐sea CO2 flux estimates if the bulk water CO2 fugacity is used. The micrometeorological eddy covariance flux technique is not affected by stratification. Here for the first time, we employ eddy covariance measurements to assess the impact of sea‐ice melt on Arctic Ocean CO2 uptake estimates. The results show that the summertime near‐surface stratification due to sea‐ice melt could lead to an ∼10% (with high uncertainty) underestimation of the annual Arctic Ocean CO2 uptake. Key Points: Seawater CO2 fugacity (fCO2w) vertical gradients are generated by fresh and cold sea‐ice melt water, which lowers surface fCO2wAir‐sea CO2 fluxes are biased when estimated using fCO2w observations from the sub‐surface (6 m depth) in sea‐ice melt areasSummertime sea‐ice melt potentially results in a 6%–17% (with high uncertainty) underestimate of annual Arctic Ocean CO2 uptake [ABSTRACT FROM AUTHOR]

Published
2021
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110. Supplementary material to "Review Article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?"

Author

Hopwood, Mark J., primary, Carroll, Dustin, additional, Dunse, Thorben, additional, Hodson, Andy, additional, Holding, Johnna M., additional, Iriarte, José L., additional, Ribeiro, Sofia, additional, Achterberg, Eric P., additional, Cantoni, Carolina, additional, Carlson, Daniel F., additional, Chierici, Melissa, additional, Clarke, Jennifer S., additional, Cozzi, Stefano, additional, Fransson, Agneta, additional, Juul-Pedersen, Thomas, additional, Winding, Mie S., additional, and Meire, Lorenz, additional

Published
2019
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111. Review Article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?

Author

Hopwood, Mark J., primary, Carroll, Dustin, additional, Dunse, Thorben, additional, Hodson, Andy, additional, Holding, Johnna M., additional, Iriarte, José L., additional, Ribeiro, Sofia, additional, Achterberg, Eric P., additional, Cantoni, Carolina, additional, Carlson, Daniel F., additional, Chierici, Melissa, additional, Clarke, Jennifer S., additional, Cozzi, Stefano, additional, Fransson, Agneta, additional, Juul-Pedersen, Thomas, additional, Winding, Mie S., additional, and Meire, Lorenz, additional

Published
2019
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113. Pelagic Ecosystem Characteristics Across the Atlantic Water Boundary Current From Rijpfjorden, Svalbard, to the Arctic Ocean During Summer (2010–2014)

Author

Hop, Haakon, primary, Assmy, Philipp, additional, Wold, Anette, additional, Sundfjord, Arild, additional, Daase, Malin, additional, Duarte, Pedro, additional, Kwasniewski, Slawomir, additional, Gluchowska, Marta, additional, Wiktor, Józef M., additional, Tatarek, Agnieszka, additional, Wiktor, Józef, additional, Kristiansen, Svein, additional, Fransson, Agneta, additional, Chierici, Melissa, additional, and Vihtakari, Mikko, additional

Published
2019
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117. Development of methods relevant to feedback management (FBM) for the krill fishery

Author

Krafft, Bjørn Arne, Lowther, Andrew, Macaulay, Gavin, Chierici, Melissa, Biuw, Martin, Renner, Angelika, klevjer, tor, Øyerhamn, Rune, cardenas, cecar, makhado, arata, Reiss, Christian, and Bergstad, Odd Aksel

Abstract

The primary objective for this project is to develop knowledge on the marine environment essential for the implementation of a Feed-Back Management (FBM) system. In terms of FBM, Marine Protected Area (MPA) development in CCAMLR Planning Domain 1 encompasses the major krill fishing grounds. Thus, data supporting FBM as an integral part of the broader management strategies of the krill fisheries within Domain 1 are critical if the fishery is to be managed by an empirical understanding of krill density, distribution, availability and predator needs. A future developed FBM system, as presented in SC-CAMLR XXXVI/BG20 requires acoustic data to be collected, processed and reported continuously during the fishing season as a measure of the available prey field. This information can be integrated with finer-scale knowledge of krill predator feeding strategies and updated through specific scientific studies at regular (multiyear) intervals. The FBM process studies will take place during the Austral summer 2018-2019. Development of methods relevant to feedback management (FBM) for the krill fishery

Published
2018

118. Arctic Ocean CO2 uptake: An improved multiyear estimate of the air-sea CO2 flux incorporating chlorophyll a concentrations

Author

Yasunaka, Sayaka, Siswanto, Eko, Olsen, Are, Hoppema, Mario, Watanabe, Eiji, Fransson, Agneta, Chierici, Melissa, Murata, Akihiko, Lauvset, Siv K., Wanninkhof, Rik, Takahashi, Taro, Kosugi, Naohiro, Omar, Abdirahman M., Heuven, Steven, Mathis, Jeremy T., and Isotope Research

Subjects
CARBON-DIOXIDE, TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES, NEURAL-NETWORK, WIND-SPEED, PHYTOPLANKTON BLOOMS, COCCOLITHOPHORE BLOOMS, UPTAKE CAPACITY, INTERANNUAL VARIABILITY, GLOBAL OCEAN, NORTH-ATLANTIC, GAS-EXCHANGE
Abstract

We estimated monthly air–sea CO2 fluxes in the Arctic Ocean and its adjacent seas north of 60∘ N from 1997 to 2014. This was done by mapping partial pressure of CO2 in the surface water (pCO2w) using a self-organizing map (SOM) technique incorporating chlorophyll a concentration (Chl a), sea surface temperature, sea surface salinity, sea ice concentration, atmospheric CO2 mixing ratio, and geographical position. We applied new algorithms for extracting Chl a from satellite remote sensing reflectance with close examination of uncertainty of the obtained Chl a values. The overall relationship between pCO2w and Chl a was negative, whereas the relationship varied among seasons and regions. The addition of Chl a as a parameter in the SOM process enabled us to improve the estimate of pCO2w, particularly via better representation of its decline in spring, which resulted from biologically mediated pCO2w reduction. As a result of the inclusion of Chl a, the uncertainty in the CO2 flux estimate was reduced, with a net annual Arctic Ocean CO2 uptake of 180 ± 130 Tg C yr−1. Seasonal to interannual variation in the CO2 influx was also calculated.

Published
2018

119. CO2 flux over young and snow-covered Arctic pack ice in winter and spring

Author

Nomura, Daiki, Granskog, Mats A., Fransson, Agneta, Chierici, Melissa, Silyakova, Anna, Ohshima, Kay, Cohen, Lana, Delille, Bruno, Hudson, Stephen R., and Dieckmann, Gerhard

Subjects
VDP::Mathematics and natural science: 400::Geosciences: 450, VDP::Matematikk og Naturvitenskap: 400::Geofag: 450, human activities
Abstract

Source at https://doi.org/10.5194/bg-15-3331-2018. Rare CO2 flux measurements from Arctic pack ice show that two types of ice contribute to the release of CO2 from the ice to the atmosphere during winter and spring: young, thin ice with a thin layer of snow and older (several weeks), thicker ice with thick snow cover. Young, thin sea ice is characterized by high salinity and high porosity, and snow-covered thick ice remains relatively warm ( > −7.5 °C) due to the insulating snow cover despite air temperatures as low as −40 °C. Therefore, brine volume fractions of these two ice types are high enough to provide favorable conditions for gas exchange between sea ice and the atmosphere even in mid-winter. Although the potential CO2 flux from sea ice decreased due to the presence of the snow, the snow surface is still a CO2 source to the atmosphere for low snow density and thin snow conditions. We found that young sea ice that is formed in leads without snow cover produces CO2 fluxes an order of magnitude higher than those in snow-covered older ice (+1.0 ± 0.6 mmol C m−2 day−1 for young ice and +0.2 ± 0.2 mmol C m−2 day−1 for older ice).

Published
2018

120. Towards structured coordination of sustained observations of Arctic change: An update from the Arctic Observing Summit 2018

Author

Eicken, Hajo, primary, Starkweather, Sandra, additional, Loescher, Hank, additional, Pirazzini, Roberta, additional, Sueyoshi, Tetsuo, additional, Bradley, Alice, additional, Koyama, Tomoko, additional, Eaton, Claire, additional, Kodama, Yuji, additional, Sobin, Jacob, additional, de Halleux, Sebastien, additional, Frank, Carsten, additional, Shichang, Kang, additional, Kang, Sung-Ho, additional, and Chierici, Melissa, additional

Published
2019
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121. Influence of glacial water and carbonate minerals on wintertime sea-ice biogeochemistry and the CO2 system in an Arctic fjord in Svalbard.

Author

Fransson, Agneta, Chierici, Melissa, Nomura, Daiki, Granskog, Mats A., Kristiansen, Svein, Martma, Tõnu, and Nehrke, Gernot

Subjects
*CARBONATE minerals, *SEA ice, *BIOGEOCHEMISTRY, *SALINITY, *DOLOMITE
Abstract

The effect of freshwater sources on wintertime sea-ice CO2 processes was studied from the glacier front to the outer Tempelfjorden, Svalbard, in sea ice, glacier ice, brine and snow. March–April 2012 was mild, and the fjord was mainly covered with drift ice, in contrast to the observed thicker fast ice in the colder April 2013. This resulted in different physical and chemical properties of the sea ice and under-ice water. Data from stable oxygen isotopic ratios and salinity showed that the sea ice at the glacier front in April 2012 contained on average 54% of frozen-in glacial meltwater. This was five times higher than in April 2013, where the ice was frozen seawater. In April 2012, the largest excess of sea-ice total alkalinity (AT), carbonate ion ([CO32−]) and bicarbonate ion concentrations ([HCO3−]) relative to salinity was mainly related to dissolved dolomite and calcite incorporated during freezing of mineral-enriched glacial water. In April 2013, the excess of these variables was mainly due to ikaite dissolution as a result of sea-ice processes. Dolomite dissolution increased sea-ice AT twice as much as ikaite and calcite dissolution, implying different buffering capacity and potential for ocean CO2 uptake in a changing climate. [ABSTRACT FROM AUTHOR]

Published
2020
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122. Nordic Seas Acidification.

Author

Fransner, Filippa, Fröb, Friederike, Tjiputra, Jerry, Chierici, Melissa, Fransson, Agneta, Jeansson, Emil, Johannessen, Truls, Jones, Elizabeth, Lauvset, Siv K., Ólafsdóttir, Sólveig R., Omar, Abdirahman, Skjelvan, Ingunn, and Olsen, Are

Subjects
DEEP-sea corals, ACIDIFICATION, OCEAN acidification, SEAS, WATER, OCEANOGRAPHIC submersibles
Abstract

Being windows to the deep ocean, the Nordic Seas play an important role in transferring anthropogenic carbon, and thus ocean acidification, to the abyss. Due to its location in high latitudes, it is further more sensitive to acidification compared with many other oceanic regions. Here we make a detailed investigation of the acidification of the Nordic Seas, and its drivers, since pre-Industrial to 2100 by using in situ measurements, gridded climatological data, and simulations from one Earth System Model (ESM). In the last 40 years, pH has decreased by 0.11 units in the Nordic Seas surface waters, a change that is twice as large as that between 1850-1980. We find that present trends are larger than expected from the increase in atmospheric CO2 alone, which is related to a faster increase in the seawater pCO2 compared with that of the atmosphere, i.e. a weakening of the pCO2 undersaturation of the Nordic Seas. The pH drop, mainly driven by an uptake of anthropogenic CO2, is significant all over the Nordic Seas, except for in the Barents Sea Opening, where it is counteracted by a significant increase in alkalinity. We also find that the acidification signal penetrates relatively deep, in some regions down to 2000 m. This has resulted in a significant decrease in the aragonite saturation state, which approaches undersaturation at 1000-2000 m in the modern ocean. Future scenarios suggest an additional drop of 0.1-0.4 units, depending on the emission scenario, in surface pH until 2100. In the worst case scenario, RCP8.5, the entire water column will be undersaturated with respect to aragonite by the end of the century, threatening Nordic Seas cold-water corals and their ecosystems. The model simulations suggest that aragonite undersaturation can be avoided at depths where the majority of the cold-water corals live in the RCP2.6 and RCP4.5 scenarios. As these results are based on one model only, we request additional observational and model studies to better quantify the transfer of anthropogenic CO2 to deep waters and its effect on future pH in the Nordic Seas. [ABSTRACT FROM AUTHOR]

Published
2020
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127. Episodic Arctic CO2 Limitation in the West Svalbard Shelf

Author

Sanz-Martín, Marina, primary, Chierici, Melissa, additional, Mesa, Elena, additional, Carrillo-de-Albornoz, Paloma, additional, Delgado-Huertas, Antonio, additional, Agustí, Susana, additional, Reigstad, Marit, additional, Kristiansen, Svein, additional, Wassmann, Paul F. J., additional, and Duarte, Carlos M., additional

Published
2018
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132. Arctic Ocean CO<sub>2</sub> uptake: an improved multiyear estimate of the air–sea CO<sub>2</sub> flux incorporating chlorophyll <i>a</i> concentrations

Author

Yasunaka, Sayaka, primary, Siswanto, Eko, additional, Olsen, Are, additional, Hoppema, Mario, additional, Watanabe, Eiji, additional, Fransson, Agneta, additional, Chierici, Melissa, additional, Murata, Akihiko, additional, Lauvset, Siv K., additional, Wanninkhof, Rik, additional, Takahashi, Taro, additional, Kosugi, Naohiro, additional, Omar, Abdirahman M., additional, van Heuven, Steven, additional, and Mathis, Jeremy T., additional

Published
2018
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135. Policy Brief TRIACID: Acidification in Nordic Waters : Status, trends and implications for marine species

Author

Carstensen, Jacob, Christensen, Jesper, Gustafsson, Bo G., Gustafsson, Erik, Chierici, Melissa, Carstensen, Jacob, Christensen, Jesper, Gustafsson, Bo G., Gustafsson, Erik, and Chierici, Melissa

Abstract

Recent studies on marine life show that the anthropogenic increase in atmospheric CO2 concentration can have negative impacts on growth and survival of groups of marine life such as corals and other calcifying organisms. Increased CO2 concentration in the atmosphere, and hence in the oceans, lead to decreasing pH or increasing acidification, a process known as ocean acidification (OA). During the last century, the CO2 concentration in the atmosphere has risen from around 280 ppm to 400 ppm; this has led to a pH decrease in the oceans of 0.1. OA currently takes place at a rate corresponding to approximately -0.02 pH unit per decade and an increase in CO2 at around 2 ppm per year. The projections for atmospheric CO2 concentration is an increase to around 1000 ppm at the end of the century, which will lower pH in the oceans by 0.3-0.4. Although this may appear relatively small, a decrease in pH of 0.1 corresponds to an increase in acidity (“free” protons) of 25%, and 0.3-0.4 corresponds to an increase of 200-250%. Coastal systems experience changes in pH over time exceeding those of the ocean by several orders of magnitude, but the field is poorly studied, and the spatial variation is large. The Baltic Sea is no exception to this. pH changes in the Baltic Sea are tightly coupled to nutrient input, alkalinity (AT) of freshwater sources in addition to increased CO2 levels and warming. Acidification trends vary substantially among coastal systems and time of year, but have been reported up to 10 times faster than OA. The TRIACID project has mapped acidification trends in the Baltic Sea during the past 40 years, in different regions, and identified areas with a general lack of data. The project has described spatial variation and trends in pH status, and the main drivers of changing pH have been identified. Given the spatial variation, the data gaps, and all the different drivers a detailed projection of the development is complicated but since we expect increasing CO2 c

Published
2018

136. Long-Term and Seasonal Trends in Estuarine and Coastal Carbonate Systems

Author

Carstensen, Jacob, Chierici, Melissa, Gustafsson, Bo G., Gustafsson, Erik, Carstensen, Jacob, Chierici, Melissa, Gustafsson, Bo G., and Gustafsson, Erik

Abstract

Coastal pH and total alkalinity are regulated by a diverse range of local processes superimposed on global trends of warming and ocean acidification, yet few studies have investigated the relative importance of different processes for coastal acidification. We describe long-term (1972-2016) and seasonal trends in the carbonate system of three Danish coastal systems demonstrating that hydrological modification, changes in nutrient inputs from land, and presence/absence of calcifiers can drastically alter carbonate chemistry. Total alkalinity was mainly governed by conservative mixing of freshwater (0.73-5.17mmolkg(-1)) with outer boundary concentrations (similar to 2-2.4mmolkg(-1)), modulated seasonally and spatially (similar to 0.1-0.2mmolkg(-1)) by calcifiers. Nitrate assimilation by primary production, denitrification, and sulfate reduction increased total alkalinity by almost 0.6mmolkg(-1) in the most eutrophic system during a period without calcifiers. Trends in pH ranged from -0.0088year(-1) to 0.021year(-1), the more extreme of these mainly driven by salinity changes in a sluice-controlled lagoon. Temperature increased 0.05 degrees Cyr(-1) across all three systems, which directly accounted for a pH decrease of 0.0008year(-1). Accounting for mixing, salinity, and temperature effects on dissociation and solubility constants, the resulting pH decline (0.0040year(-1)) was about twice the ocean trend, emphasizing the effect of nutrient management on primary production and coastal acidification. Coastal pCO(2) increased similar to 4 times more rapidly than ocean rates, enhancing CO2 emissions to the atmosphere. Indeed, coastal systems undergo more drastic changes than the ocean and coastal acidification trends are substantially enhanced from nutrient reductions to address coastal eutrophication.

Published
2018
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137. The state of the polar oceans 2018: making sense of our changing world

Author

Meredith, Michael, Sundfjord, Arild, Henson, Stephanie, Meijers, Andrew, Murphy, Eugene, Bellerby, Richard, Daase, Malin, Cottier, Finlo, Belchier, Mark, Chierici, Melissa, Ellingsen, Ingrid, Falk-Petersen, Stig, Hill, Simeon, Holland, Paul, Tarling, Geraint, Trathan, Phil, Turner, John, Wilkinson, Jeremy, Batchellier, Layla, Capper, Linda, Oliver, Jamie, Meredith, Michael, Sundfjord, Arild, Henson, Stephanie, Meijers, Andrew, Murphy, Eugene, Bellerby, Richard, Daase, Malin, Cottier, Finlo, Belchier, Mark, Chierici, Melissa, Ellingsen, Ingrid, Falk-Petersen, Stig, Hill, Simeon, Holland, Paul, Tarling, Geraint, Trathan, Phil, Turner, John, Wilkinson, Jeremy, Batchellier, Layla, Capper, Linda, and Oliver, Jamie

Abstract

The vast frozen worlds of the Polar Regions are a major component of the Earth’s global climate system. The polar oceans are amongst the least understood environments on our planet. They respond to global temperature change; absorb heat and carbon from the atmosphere, including that produced by humans; they sustain millions of seabirds, whales and fish; and provide food for a hungry world. These oceans keep our planet cool and supply other oceans with nutrients. But, because of their remoteness and inhospitable nature, data coverage is extremely sparse. Understanding the polar oceans is absolutely key to understanding the big questions about our global environment. By working together scientists create observing systems to collect and interpret crucial scientific data that shapes policy, protects the environment and ultimately improves people’s lives. Recent technological advances mean that scientists can now combine high-quality land and ship-based observations with high-quality satellite data from previously-inaccessible areas. Over decades studies have shed new light on the consequences of the shrinking sea ice for ocean circulation, climate and the ecosystem. Surveys of the deep ocean have yielded vital discoveries about marine biodiversity and informed an international census of marine life. Long-term studies have helped understand the marine food chain, and have provided critical scientific information to underpin the sustainable management of fisheries. The report demonstrates that we are advancing our understanding. There remains, however, an urgent need for further investigations if we are to be, as we absolutely must, able to provide the understanding needed to help people live with, and adapt to, environmental change.

Published
2018

138. Spatiotemporal variability of barium in Arctic sea-ice and seawater

Author

Hendry, Katharine R., Pyle, Kimberley M., Butler, G. Barney, Cooper, Adam, Fransson, Agneta, Chierici, Melissa, Leng, Melanie J., Meyer, Amelie, Dodd, Paul A., Hendry, Katharine R., Pyle, Kimberley M., Butler, G. Barney, Cooper, Adam, Fransson, Agneta, Chierici, Melissa, Leng, Melanie J., Meyer, Amelie, and Dodd, Paul A.

Abstract

Freshwater export from the Arctic is critical in determining the density of water at sites of North Atlantic deep water formation, which in turn influences the global flux of oceanic heat and nutrients. We need geochemical tracers and high‐resolution observations to refine our freshwater budgets and constrain models for future change. The use of seawater barium concentrations in the Arctic Ocean as a freshwater tracer relies on the conservative behaviour of barium in seawater; whilst this has been shown to be an unreliable assumption in Arctic summers, there are a lack of studies observing seasonal progressions. Here, we present barium concentrations from seawater and sea‐ice collected during the Norwegian Young Sea ICE expedition from boreal winter into summer. We use other tracers (salinity, oxygen isotopes and alkalinity) to reconstruct freshwater inputs and calculate a barium “deficit” that can be attributed to non‐conservative processes. We locate a deficit in winter when biological production is low, which we attribute to uptake by barite formation associated with old organic matter or by internal sea‐ice processes. We also find a significant barium deficit during the early spring bloom, consistent with uptake into organic‐matter associated microenvironments. However, in summer there no strong barium deficit near the surface, despite high biological production and organic carbon standing stocks, perhaps reflecting phytoplankton assemblage changes, and/or rapid internal cycling. Our findings challenge the assumptions surrounding the use of barium as an Arctic freshwater tracer, and highlight the need to improve our understanding of barium in sea‐ice environments.

Published
2018

139. CO2 flux over young and snow-covered Arctic pack ice in winter and spring

Author

1000070550739, Nomura, Daiki, Granskog, Mats A., Fransson, Agneta, Chierici, Melissa, Silyakova, Anna, 1000030185251, Ohshima, Kay I., Cohen, Lana, Delille, Bruno, Hudson, Stephen R., Dieckmann, Gerhard S., 1000070550739, Nomura, Daiki, Granskog, Mats A., Fransson, Agneta, Chierici, Melissa, Silyakova, Anna, 1000030185251, Ohshima, Kay I., Cohen, Lana, Delille, Bruno, Hudson, Stephen R., and Dieckmann, Gerhard S.

Abstract

Rare CO2 flux measurements from Arctic pack ice show that two types of ice contribute to the release of CO2 from the ice to the atmosphere during winter and spring: young, thin ice with a thin layer of snow and older (several weeks), thicker ice with thick snow cover. Young, thin sea ice is characterized by high salinity and high porosity, and snow-covered thick ice remains relatively warm (> -7.5 degrees C) due to the insulating snow cover despite air temperatures as low as -40 degrees C. Therefore, brine volume fractions of these two ice types are high enough to provide favorable conditions for gas exchange between sea ice and the atmosphere even in mid-winter. Although the potential CO2 flux from sea ice decreased due to the presence of the snow, the snow surface is still a CO2 source to the atmosphere for low snow density and thin snow conditions. We found that young sea ice that is formed in leads without snow cover produces CO2 fluxes an order of magnitude higher than those in snow-covered older ice (+1.0 +/- 0.6 mmol Cm-2 day(-1) for young ice and +0.2 +/- 0.2 mmol Cm-2 day(-1) for older ice).

Published
2018

140. Using natural analogues to investigate the effects of climate change and ocean acidification on Northern ecosystems

Author

Rastrick, Samuel P. S., Graham, Helen, Azetsu-Scott, Kumiko, Calosi, Piero, Chierici, Melissa, Fransson, Agneta, Hop, Haakon, Hall-Spencer, Jason, Milazzo, Marco, Thor, Peter, Kutti, Tina, Rastrick, Samuel P. S., Graham, Helen, Azetsu-Scott, Kumiko, Calosi, Piero, Chierici, Melissa, Fransson, Agneta, Hop, Haakon, Hall-Spencer, Jason, Milazzo, Marco, Thor, Peter, and Kutti, Tina

Abstract

Northern oceans are in a state of rapid transition. Still, our knowledge of the likely effects of climate change and ocean acidification on key species in the food web, functionally important habitats and the structure of Arctic and sub-Arctic ecosystems is limited and based mainly on short-term laboratory studies on single species. This review discusses how tropical and temperate natural analogues of carbonate chemistry drivers, such as CO2 vents, have been used to further our knowledge of the sensitivity of biological systems to predicted climate change, and thus assess the capacity of different species to show long-term acclimation and adaptation to elevated levels of pCO2. Natural analogues have also provided the means to scale-up from single-species responses to community and ecosystem level responses. However, to date the application of such approaches is limited in high latitude systems. A range of Arctic and sub-Arctic sites, including CO2 vents, methane cold seeps, estuaries, up-welling areas, and polar fronts, that encompass gradients of pH, carbonate saturation state, and alkalinity, are suggested for future high latitude, in-situ ocean acidification research. It is recommended that combinations of monitoring of the chemical oceanography, observational, and experimental (in situ and laboratory) studies of organisms around these natural analogues be used to attain better predictions of the impacts of ocean acidification and climate change on high latitude species and ecosystems.

Published
2018

142. Episodic arctic CO2 limitation in the west svalbard shelf

Author

Norwegian Research Council, Sanz-Martín, Marina, Chierici, Melissa, Mesa, Elena, Carrillo-de-Albornoz, Paloma, Delgado Huertas, Antonio, Agustí, Susana, Reigstad, Marit, Kristiansen, Svein, Wassmann, Paul F., Duarte, C.M., Norwegian Research Council, Sanz-Martín, Marina, Chierici, Melissa, Mesa, Elena, Carrillo-de-Albornoz, Paloma, Delgado Huertas, Antonio, Agustí, Susana, Reigstad, Marit, Kristiansen, Svein, Wassmann, Paul F., and Duarte, C.M.

Abstract

The European Sector of the Arctic Ocean is characterized by low CO concentrations in seawater during spring and summer, largely due to strong biological uptake driven by extensive plankton blooms in spring. The spring plankton bloom is eventually terminated by nutrient depletion and grazing. However, low CO concentrations in seawater and low atmospheric resupply of CO can cause episodes during which the phytoplankton growth is limited by CO2. Here, we show that gross primary production (GPP) of Arctic plankton communities increases from 32 to 72% on average with CO additions in spring. Enhanced GPP with CO additions occur during episodes of high productivity, low CO concentration and in the presence of dissolved inorganic nutrients. However, during summer the addition of CO supresses planktonic Arctic GPP. Events of CO limitation in spring may contribute to the termination of the Arctic spring plankton blooms. The stimulation of GPP by CO during the spring bloom provides a biotic feedback loop that might influence the global role played by the Arctic Ocean as a CO sink in the future.

Published
2018

146. Effects of sea-ice and biogeochemical processes and storms on under-ice water fCO2 during the winter-spring transition in the high Arctic Ocean: Implications for sea-air CO2 fluxes

Author

Fransson, Agneta Ingrid, Chierici, Melissa, Skjelvan, Ingunn, Olsen, Are, Assmy, Philipp, Peterson, Algot Kristoffer, Spreen, Gunnar, and Ward, Brian

Subjects
atmospheric co2, gas-exchange, variability, system, surface-water, carbon-dioxide, north, southern-ocean, wind-speed, seawater
Abstract

We performed measurements of carbon dioxide fugacity (fCO(2)) in the surface water under Arctic sea ice from January to June 2015 during the Norwegian young sea ICE (N-ICE2015) expedition. Over this period, the ship drifted with four different ice floes and covered the deep Nansen Basin, the slopes north of Svalbard, and the Yermak Plateau. This unique winter-to-spring data set includes the first winter-time under-ice water fCO(2) observations in this region. The observed under-ice fCO(2) ranged between 315 mu atm in winter and 153 mu atm in spring, hence was undersaturated relative to the atmospheric fCO(2). Although the sea ice partly prevented direct CO2 exchange between ocean and atmosphere, frequently occurring leads and breakup of the ice sheet promoted sea-air CO2 fluxes. The CO2 sink varied between 0.3 and 86 mmol C m(-2) d(-1), depending strongly on the open-water fractions (OW) and storm events. The maximum sea-air CO2 fluxes occurred during storm events in February and June. In winter, the main drivers of the change in under-ice water fCO(2) were dissolution of CaCO3 (ikaite) and vertical mixing. In June, in addition to these processes, primary production and sea-air CO2 fluxes were important. The cumulative loss due to CaCO3 dissolution of 0.7 mol C m(-2) in the upper 10 m played a major role in sustaining the undersaturation of fCO(2) during the entire study. The relative effects of the total fCO(2) change due to CaCO3 dissolution was 38%, primary production 26%, vertical mixing 16%, sea-air CO2 fluxes 16%, and temperature and salinity insignificant.

Published
2017

147. A multi-decade record of high-quality fCO2 data in version 3 of the Surface Ocean CO2 Atlas (SOCAT)

Author

Bakker, Dorothee C. E., Pfeil, Benjamin, Landa, Camilla S., Metzl, Nicolas, O'Brien, Kevin M., Olsen, Are, Smith, Karl M., Cosca, Catherine E., Harasawa, Sumiko, Jones, Stephen D., Nakaoka, Shin-Ichiro, Nojiri, Yukihiro, Schuster, Ute, Steinhoff, Tobias, Sweeney, Colm, Takahashi, Taro, Tilbrook, Bronte, Wada, Chisato, Wanninkhof, Rik H., Alin, Simone R., Balestrini, Carlos F., Barbero, Leticia, Bates, Nicholas R., Bianchi, Alejandro A., Bonou, Frédéric, Boutin, Jacqueline, Bozec, Yann, Burger, Eugene F., Cai, Wei-Jun, Castle, Robert D., Chen, Liqi, Chierici, Melissa, Currie, Kim, Evans, Wiley, Featherstone, Charles, Feely, Richard A., Fransson, Agneta, Goyet, Catherine, Greenwood, Naomi, Gregor, Luke, Hankin, Steven, Hardman-Mountford, Nick J., Harlay, Jérôme, Hauck, Judith, Hoppema, Mario, Humphreys, Matthew P., Hunt, Christopher W., Huss, Betty, Ibánhez, J. Severino P., Johannessen, Truls, Keeling, Ralph F., Kitidis, Vassilis, Körtzinger, Arne, Kozyr, Alex, Krasakopoulou, Evangelia, Kuwata, Akira, Landschützer, Peter, Lauvset, Siv K., Lefèvre, Nathalie, Lo Monaco, Claire, Manke, Ansley B., Mathis, Jeremy T., Merlivat, Liliane, Millero, Frank J., Monteiro, Pedro M. S., Munro, David R., Murata, Akihiko, Newberger, Timothy, Omar, Abdirahman M., Ono, Tsuneo, Paterson, Kristina, Pearce, David, Pierrot, Denis, Robbins, Lisa L., Saito, Shu, Salisbury, Joseph E., Schlitzer, Reiner, Schneider, Bernd, Schweitzer, Roland, Sieger, Rainer, Skjelvan, Ingunn, Sullivan, Kevin F., Sutherland, Stewart C., Sutton, Adrienne J., Tadokoro, Kazuaki, Telszewski, Maciej, Tuma, Matthias, van Heuven, Steven M. A. C., Vandemark, Doug, Ward, Brian, Watson, Andrew J., Xu, Suqing, Centre for Ocean and Atmospheric, school of Environmental Sciences, University of East Anglia [Norwich] (UEA), University of Bergen (UiB), Bjerknes Centre for Climate Research (BCCR), Department of Biological Sciences [Bergen] (BIO / UiB), University of Bergen (UiB)-University of Bergen (UiB), Équipe CO2 (E-CO2), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), 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)), 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), NOAA Pacific Marine Environmental Laboratory [Seattle] (PMEL), National Oceanic and Atmospheric Administration (NOAA), Joint Institute for the Study of the Atmosphere and Ocean (JISAO), University of Washington [Seattle], National Institute for Environmental Studies (NIES), University of Exeter, Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), NOAA Earth System Research Laboratory (ESRL), Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], CSIRO Marine and Atmospheric Research (CSIRO-MAR), Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), NOAA Atlantic Oceanographic and Meteorological Laboratory (AOML), Departamento de Oceanografia, Servicio de Hidrografía Naval, Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School for Marine and Atmospheric Science (CIMAS), Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami [Coral Gables]-University of Miami [Coral Gables], Ocean and Earth Science [Southampton], University of Southampton-National Oceanography Centre (NOC), Departmento de Engenharia de Produção, Centro de Estudos e Ensaios em Risco e Modelagem Ambiental, Universidade Federal de Pernambuco [Recife] (UFPE), Interactions et Processus au sein de la couche de Surface Océanique (IPSO), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), School of Marine Science and Policy, University of Delaware [Newark], The Third Institute of Oceanography SOA, Department of Marine Sciences, University of Gothenburg (GU), National Institute of Water and Atmospheric Research [Wellington] (NIWA), Norwegian Polar Institute, Institut de Modélisation et d'Analyses en géo-environnement et santé - Espace Développement (IMAGES-Espace DEV), UMR 228 Espace-Dev, Espace pour le développement, Institut de Recherche pour le Développement (IRD)-Université de Perpignan Via Domitia (UPVD)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Montpellier (UM)-Université de Guyane (UG)-Université des Antilles (UA)-Institut de Recherche pour le Développement (IRD)-Université de Perpignan Via Domitia (UPVD)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Montpellier (UM)-Université de Guyane (UG)-Université des Antilles (UA), Centre for Environment, Fisheries and Aquaculture Science [Lowestoft] (CEFAS), Ocean Systems and Climate Group, CSIR, CSIRO Oceans and Atmosphere, CISRO Oceans and Atmosphere, University of Hawai‘i [Mānoa] (UHM), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Ocean Process Analysis Laboratory, University of New Hampshire (UNH), IRD Lago Sul, Brazil, University of California [San Diego] (UC San Diego), University of California (UC), Plymouth Marine Laboratory (PML), Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, University of the Aegean, Tohoku National Fisheries Research Institute, National Fisheries Research Institute, Max-Planck-Institut für Meteorologie (MPI-M), Max-Planck-Gesellschaft, Geophysical Institute [Bergen] (GFI / BiU), Austral, Boréal et Carbone (ABC), Department of Ocean Sciences, University of Miami [Coral Gables], Department of Atmospheric and Oceanic Sciences [Boulder] (ATOC), University of Colorado [Boulder], Institute of Arctic Alpine Research [University of Colorado Boulder] (INSTAAR), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado [Boulder]-National Oceanic and Atmospheric Administration (NOAA), National Research Institute for Fisheries Science,Japan Fisheries Research and Education Agency, Université Paris Diderot - Paris 7 (UPD7), United States Geological Survey [Reston] (USGS), Japan Meteorological Agency (JMA), Ocean Process Analysis Laboratory (OPAL), Leibniz Institute for Baltic Sea Research Warnemünde, Weathertop consulting LLC, International Ocean Carbon Coordination Project, WCRP Joint planning staff, World Meteorological Organization (WCRP), Royal Netherlands Institute for Sea Research (NIOZ), AirSea Laboratory, School of Physics and Ryan Institute, National University of Ireland [Galway] (NUI Galway), 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)), University of Leeds, College of Life and Environmental Sciences [Exeter], Met Eireann, CSIRO Wealth from Oceans National Research Flagship and Antarctic Climate and Ecosystems CRC, Helmholtz Zentrum für Umweltforschung = Helmholtz Centre for Environmental Research (UFZ), Bermuda Institute of Ocean Sciences (BIOS), Centre de résonance magnétique des systèmes biologiques (CRMSB), Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), CHImie Marine (CHIM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Department of Chemistry, Computer Science Department (UBC-Computer Science), University of British Columbia (UBC), Laboratoire de Biophysique et Dynamique des Systèmes Intégrés (BDSI), Université de Perpignan Via Domitia (UPVD), Oceans and Atmosphere Flagship (CSIRO), CSIRO Oceans and Atmosphere Flagship, Department of Oceanography (DOCEAN), Federal University of Pernambuco [Recife], University of California, Plymouth Marine Laboratory, Christian-Albrechts-Universität zu Kiel (CAU), Department of Civil and Environmental Engineering [Berkeley] (CEE), University of California [Berkeley], University of California-University of California, University of Wisconsin Whitewater, National Institute of Advanced Industrial Science and Technology (AIST), Department of Computer Science [Royal Holloway], Royal Holloway [University of London] (RHUL), Cooperative Institute for Marine and Atmospheric Studies (CIMAS), Max Planck Institute for Chemical Ecology, School of Physics [NUI Galway], School of Environmental Sciences [Norwich], College of Life and Environmental Sciences, University of Exeter, Université de Guyane (UG)-Université des Antilles (UA)-Institut de Recherche pour le Développement (IRD)-Université de Perpignan Via Domitia (UPVD)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Montpellier (UM)-Université de Guyane (UG)-Université des Antilles (UA)-Institut de Recherche pour le Développement (IRD)-Université de Perpignan Via Domitia (UPVD)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Montpellier (UM), Institute of Arctic and Alpine Research (INSTAAR), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)

Subjects
lcsh:GE1-350, lcsh:Geology, [SDU]Sciences of the Universe [physics], lcsh:QE1-996.5, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], lcsh:Environmental sciences, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract

The Surface Ocean CO2 Atlas (SOCAT) is a synthesis of quality-controlled fCO2 (fugacity of carbon dioxide) values for the global surface oceans and coastal seas with regular updates. Version 3 of SOCAT has 14.7 million fCO2 values from 3646 data sets covering the years 1957 to 2014. This latest version has an additional 4.6 million fCO2 values relative to version 2 and extends the record from 2011 to 2014. Version 3 also significantly increases the data availability for 2005 to 2013. SOCAT has an average of approximately 1.2 million surface water fCO2 values per year for the years 2006 to 2012. Quality and documentation of the data has improved. A new feature is the data set quality control (QC) flag of E for data from alternative sensors and platforms. The accuracy of surface water fCO2 has been defined for all data set QC flags. Automated range checking has been carried out for all data sets during their upload into SOCAT. The upgrade of the interactive Data Set Viewer (previously known as the Cruise Data Viewer) allows better interrogation of the SOCAT data collection and rapid creation of high-quality figures for scientific presentations. Automated data upload has been launched for version 4 and will enable more frequent SOCAT releases in the future. High-profile scientific applications of SOCAT include quantification of the ocean sink for atmospheric carbon dioxide and its long-term variation, detection of ocean acidification, as well as evaluation of coupled-climate and ocean-only biogeochemical models. Users of SOCAT data products are urged to acknowledge the contribution of data providers, as stated in the SOCAT Fair Data Use Statement. This ESSD (Earth System Science Data) "living data" publication documents the methods and data sets used for the assembly of this new version of the SOCAT data collection and compares these with those used for earlier versions of the data collection (Pfeil et al., 2013; Sabine et al., 2013; Bakker et al., 2014). Individual data set files, included in the synthesis product, can be downloaded here: doi:10.1594/PANGAEA.849770. The gridded products are available here: doi:10.3334/CDIAC/OTG.SOCAT_V3_GRID.

Published
2016
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149. Arctic Ocean CO2 uptake: an improved multi-year estimate of the air–sea CO2 flux incorporating chlorophyll-a concentrations

Author

Yasunaka, Sayaka, primary, Siswanto, Eko, additional, Olsen, Are, additional, Hoppema, Mario, additional, Watanabe, Eiji, additional, Fransson, Agneta, additional, Chierici, Melissa, additional, Murata, Akihiko, additional, Lauvset, Siv K., additional, Wanninkhof, Rik, additional, Takahashi, Taro, additional, Kosugi, Naohiro, additional, Omar, Abdirahman M., additional, van Heuven, Steven, additional, and Mathis, Jeremy T., additional

Published
2017
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