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16. Net heterotrophy in High Arctic first-year and multi-year spring sea ice

Author

Campbell, Karley, Lange, B. A., Landy, J. C., Katlein, Christian, Nicolaus, Marcel, Anhaus, Philipp, Matero, I., Gradinger, R., Charette, J., Duerksen, S., Tremblay, P., Rysgaard, S., Tranter, M., Haas, Christian, Michel, C., Campbell, Karley, Lange, B. A., Landy, J. C., Katlein, Christian, Nicolaus, Marcel, Anhaus, Philipp, Matero, I., Gradinger, R., Charette, J., Duerksen, S., Tremblay, P., Rysgaard, S., Tranter, M., Haas, Christian, and Michel, C.

Abstract

The net productivity of sea ice is determined by the physical and geochemical characteristics of the ice–ocean system and the activity of organisms inhabiting the ice. Differences in habitat suitability between first-year and multi-year sea ice can affect the ice algal community composition and acclimation state, introducing considerable variability to primary production within each ice type. In this study, we characterized the biogeochemical variability between adjacent first-year and multi-year sea ice floes in the Lincoln Sea of the Canadian High Arctic, during the May 2018 Multidisciplinary Arctic Program—Last Ice sampling campaign. Combining measurements of transmitted irradiance from a remotely operated underwater vehicle with laboratory-based oxygen optode incubations, this work shows widespread heterotrophy (net oxygen uptake) in the bottom 10 cm of both ice types, particularly in thick multi-year ice (>2.4 m) and early morning of the 24-h day. Algal acclimation state and species composition varied between ice types despite similar net community production due to widespread light and nutrient limitation. The first-year ice algal community was increasingly dominated over spring by the potentially toxin-producing genus Pseudonitzschia that was acclimated to high and variable light conditions characteristic of a thinner ice habitat with mobile snow cover. In comparison, the multi-year ice harbored more shade-acclimated algae of mixed composition.This work highlights the potential for heterotrophy in sea ice habitats of the High Arctic, including first measurements of such O2-uptake in multi-year ice floes. Observed differences in photophysiology between algae of these sea ice types suggests that a shift toward higher light availability and a younger sea ice cover with climate change does not necessarily result in a more productive system. Instead, it may favor future sea ice algal communities of different species composition, with lower photosynthetic potential

Published
2022

17. Particle dynamics and vertical fluxesin in the central Arctic Ocean during the MOSAiC expedition

Author

Gardner, J., Assmy, P., Fong, A.A., Niehoff, B., Waite, A., Nöthig, E.-M., Hoppe, C.J.M., Engel, A., Rogge, A., Chen, J., Ren, J., Jin, H., Zhuang, J., Lan, M., Jianfeng, H., Flores, H., Havermans, C., Wollenburg, J., Olsen, L., Iversen, M., Müller, O., Geibert, W., Reigstad, M., Gradinger, R., Gardner, J., Assmy, P., Fong, A.A., Niehoff, B., Waite, A., Nöthig, E.-M., Hoppe, C.J.M., Engel, A., Rogge, A., Chen, J., Ren, J., Jin, H., Zhuang, J., Lan, M., Jianfeng, H., Flores, H., Havermans, C., Wollenburg, J., Olsen, L., Iversen, M., Müller, O., Geibert, W., Reigstad, M., and Gradinger, R.

Published
2022

19. Overview of the MOSAiC expedition : Atmosphere

Author

Shupe, M. D., Rex, M., Blomquist, B., G. Persson, P. O., Schmale, J., Uttal, T., Althausen, D., Angot, H., Archer, S., Bariteau, L., Beck, I., Bilberry, J., Bucci, S., Buck, C., Boyer, M., Brasseur, Z., Brooks, I. M., Calmer, R., Cassano, J., Castro, V., Chu, D., Costa, D., Cox, C. J., Creamean, J., Crewell, S., Dahlke, S., Damm, E., de Boer, G., Deckelmann, H., Dethloff, K., Dütsch, M., Ebell, K., Ehrlich, A., Ellis, J., Engelmann, R., Fong, A. A., Frey, M. M., Gallagher, M. R., Ganzeveld, L., Gradinger, R., Graeser, J., Greenamyer, V., Griesche, H., Griffiths, S., Hamilton, J., Heinemann, G., Helmig, D., Herber, A., Heuzé, C., Hofer, J., Houchens, T., Howard, D., Inoue, J., Jacobi, H. -W, Jaiser, R., Jokinen, T., Jourdan, O., Jozef, G., King, W., Kirchgaessner, A., Klingebiel, M., Krassovski, M., Krumpen, T., Lampert, A., Landing, W., Laurila, T., Lawrence, D., Lonardi, M., Loose, B., Lüpkes, C., Maahn, M., Macke, A., Maslowski, W., Marsay, C., Maturilli, M., Mech, M., Morris, S., Moser, M., Nicolaus, M., Ortega, P., Osborn, J., Pätzold, F., Perovich, D. K., Petäjä, T., Pilz, C., Pirazzini, R., Posman, K., Powers, H., Pratt, K. A., Preußer, A., Quéléver, L., Radenz, M., Rabe, B., Rinke, A., Sachs, T., Schulz, A., Siebert, H., Silva, T., Solomon, A., Sommerfeld, A., Spreen, G., Stephens, M., Stohl, A., Svensson, Gunilla, Uin, J., Viegas, J., Voigt, C., von der Gathen, P., Wehner, B., Welker, J. M., Wendisch, M., Werner, M., Xie, Z., Yue, F., Shupe, M. D., Rex, M., Blomquist, B., G. Persson, P. O., Schmale, J., Uttal, T., Althausen, D., Angot, H., Archer, S., Bariteau, L., Beck, I., Bilberry, J., Bucci, S., Buck, C., Boyer, M., Brasseur, Z., Brooks, I. M., Calmer, R., Cassano, J., Castro, V., Chu, D., Costa, D., Cox, C. J., Creamean, J., Crewell, S., Dahlke, S., Damm, E., de Boer, G., Deckelmann, H., Dethloff, K., Dütsch, M., Ebell, K., Ehrlich, A., Ellis, J., Engelmann, R., Fong, A. A., Frey, M. M., Gallagher, M. R., Ganzeveld, L., Gradinger, R., Graeser, J., Greenamyer, V., Griesche, H., Griffiths, S., Hamilton, J., Heinemann, G., Helmig, D., Herber, A., Heuzé, C., Hofer, J., Houchens, T., Howard, D., Inoue, J., Jacobi, H. -W, Jaiser, R., Jokinen, T., Jourdan, O., Jozef, G., King, W., Kirchgaessner, A., Klingebiel, M., Krassovski, M., Krumpen, T., Lampert, A., Landing, W., Laurila, T., Lawrence, D., Lonardi, M., Loose, B., Lüpkes, C., Maahn, M., Macke, A., Maslowski, W., Marsay, C., Maturilli, M., Mech, M., Morris, S., Moser, M., Nicolaus, M., Ortega, P., Osborn, J., Pätzold, F., Perovich, D. K., Petäjä, T., Pilz, C., Pirazzini, R., Posman, K., Powers, H., Pratt, K. A., Preußer, A., Quéléver, L., Radenz, M., Rabe, B., Rinke, A., Sachs, T., Schulz, A., Siebert, H., Silva, T., Solomon, A., Sommerfeld, A., Spreen, G., Stephens, M., Stohl, A., Svensson, Gunilla, Uin, J., Viegas, J., Voigt, C., von der Gathen, P., Wehner, B., Welker, J. M., Wendisch, M., Werner, M., Xie, Z., and Yue, F.

Abstract

With the Arctic rapidly changing, the needs to observe, understand, and model the changes are essential. To support these needs, an annual cycle of observations of atmospheric properties, processes, and interactions were made while drifting with the sea ice across the central Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition from October 2019 to September 2020. An international team designed and implemented the comprehensive program to document and characterize all aspects of the Arctic atmospheric system in unprecedented detail, using a variety of approaches, and across multiple scales. These measurements were coordinated with other observational teams to explore crosscutting and coupled interactions with the Arctic Ocean, sea ice, and ecosystem through a variety of physical and biogeochemical processes. This overview outlines the breadth and complexity of the atmospheric research program, which was organized into 4 subgroups: atmospheric state, clouds and precipitation, gases and aerosols, and energy budgets. Atmospheric variability over the annual cycle revealed important influences from a persistent large-scale winter circulation pattern, leading to some storms with pressure and winds that were outside the interquartile range of past conditions suggested by long-term reanalysis. Similarly, the MOSAiC location was warmer and wetter in summer than the reanalysis climatology, in part due to its close proximity to the sea ice edge. The comprehensiveness of the observational program for characterizing and analyzing atmospheric phenomena is demonstrated via a winter case study examining air mass transitions and a summer case study examining vertical atmospheric evolution. Overall, the MOSAiC atmospheric program successfully met its objectives and was the most comprehensive atmospheric measurement program to date conducted over the Arctic sea ice. The obtained data will support a broad range of coupled-system s

Published
2022
Full Text
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20. Overview of the MOSAiC expedition:atmosphere

Author

Shupe, M. D. (Matthew D.), Rex, M. (Markus), Blomquist, B. (Byron), Persson, P. O. (P. Ola G.), Schmale, J. (Julia), Uttal, T. (Taneil), Althausen, D. (Dietrich), Angot, H. (Helene), Archer, S. (Stephen), Bariteau, L. (Ludovic), Beck, I. (Ivo), Bilberry, J. (John), Bucci, S. (Silvia), Buck, C. (Clifton), Boyer, M. (Matt), Brasseur, Z. (Zoe), Brooks, I. M. (Ian M.), Calmer, R. (Radiance), Cassano, J. (John), Castro, V. (Vagner), Chu, D. (David), Costa, D. (David), Cox, C. J. (Christopher J.), Creamean, J. (Jessie), Crewell, S. (Susanne), Dahlke, S. (Sandro), Damm, E. (Ellen), de Boer, G. (Gijs), Deckelmann, H. (Holger), Dethloff, K. (Klaus), Duetsch, M. (Marina), Ebell, K. (Kerstin), Ehrlich, A. (Andre), Ellis, J. (Jody), Engelmann, R. (Ronny), Fong, A. A. (Allison A.), Frey, M. M. (Markus M.), Gallagher, M. R. (Michael R.), Ganzeveld, L. (Laurens), Gradinger, R. (Rolf), Graeser, J. (Juergen), Greenamyer, V. (Vernon), Griesche, H. (Hannes), Griffiths, S. (Steele), Hamilton, J. (Jonathan), Heinemann, G. (Guenther), Helmig, D. (Detlev), Herber, A. (Andreas), Heuze, C. (Celine), Hofer, J. (Julian), Houchens, T. (Todd), Howard, D. (Dean), Inoue, J. (Jun), Jacobi, H.-W. (Hans-Werner), Jaiser, R. (Ralf), Jokinen, T. (Tuija), Jourdan, O. (Olivier), Jozef, G. (Gina), King, W. (Wessley), Kirchgaessner, A. (Amelie), Klingebiel, M. (Marcus), Krassovski, M. (Misha), Krumpen, T. (Thomas), Lampert, A. (Astrid), Landing, W. (William), Laurila, T. (Tiia), Lawrence, D. (Dale), Lonardi, M. (Michael), Loose, B. (Brice), Luepkes, C. (Christof), Maahn, M. (Maximilian), Macke, A. (Andreas), Maslowski, W. (Wieslaw), Marsay, C. (Christopher), Maturilli, M. (Marion), Mech, M. (Mario), Morris, S. (Sara), Moser, M. (Manuel), Nicolaus, M. (Marcel), Ortega, P. (Paul), Osborn, J. (Jackson), Paetzold, F. (Falk), Perovich, D. K. (Donald K.), Petäjä, T. (Tuukka), Pilz, C. (Christian), Pirazzini, R. (Roberta), Posman, K. (Kevin), Powers, H. (Heath), Pratt, K. A. (Kerri A.), Preusser, A. (Andreas), Quelever, L. (Lauriane), Radenz, M. (Martin), Rabe, B. (Benjamin), Rinke, A. (Annette), Sachs, T. (Torsten), Schulz, A. (Alexander), Siebert, H. (Holger), Silva, T. (Tercio), Solomon, A. (Amy), Sommerfeld, A. (Anja), Spreen, G. (Gunnar), Stephens, M. (Mark), Stohl, A. (Andreas), Svensson, G. (Gunilla), Uin, J. (Janek), Viegas, J. (Juarez), Voigt, C. (Christiane), von der Gathen, P. (Peter), Wehner, B. (Birgit), Welker, J. M. (Jeffrey M.), Wendisch, M. (Manfred), Werner, M. (Martin), Xie, Z. (ZhouQing), Yue, F. (Fange), Shupe, M. D. (Matthew D.), Rex, M. (Markus), Blomquist, B. (Byron), Persson, P. O. (P. Ola G.), Schmale, J. (Julia), Uttal, T. (Taneil), Althausen, D. (Dietrich), Angot, H. (Helene), Archer, S. (Stephen), Bariteau, L. (Ludovic), Beck, I. (Ivo), Bilberry, J. (John), Bucci, S. (Silvia), Buck, C. (Clifton), Boyer, M. (Matt), Brasseur, Z. (Zoe), Brooks, I. M. (Ian M.), Calmer, R. (Radiance), Cassano, J. (John), Castro, V. (Vagner), Chu, D. (David), Costa, D. (David), Cox, C. J. (Christopher J.), Creamean, J. (Jessie), Crewell, S. (Susanne), Dahlke, S. (Sandro), Damm, E. (Ellen), de Boer, G. (Gijs), Deckelmann, H. (Holger), Dethloff, K. (Klaus), Duetsch, M. (Marina), Ebell, K. (Kerstin), Ehrlich, A. (Andre), Ellis, J. (Jody), Engelmann, R. (Ronny), Fong, A. A. (Allison A.), Frey, M. M. (Markus M.), Gallagher, M. R. (Michael R.), Ganzeveld, L. (Laurens), Gradinger, R. (Rolf), Graeser, J. (Juergen), Greenamyer, V. (Vernon), Griesche, H. (Hannes), Griffiths, S. (Steele), Hamilton, J. (Jonathan), Heinemann, G. (Guenther), Helmig, D. (Detlev), Herber, A. (Andreas), Heuze, C. (Celine), Hofer, J. (Julian), Houchens, T. (Todd), Howard, D. (Dean), Inoue, J. (Jun), Jacobi, H.-W. (Hans-Werner), Jaiser, R. (Ralf), Jokinen, T. (Tuija), Jourdan, O. (Olivier), Jozef, G. (Gina), King, W. (Wessley), Kirchgaessner, A. (Amelie), Klingebiel, M. (Marcus), Krassovski, M. (Misha), Krumpen, T. (Thomas), Lampert, A. (Astrid), Landing, W. (William), Laurila, T. (Tiia), Lawrence, D. (Dale), Lonardi, M. (Michael), Loose, B. (Brice), Luepkes, C. (Christof), Maahn, M. (Maximilian), Macke, A. (Andreas), Maslowski, W. (Wieslaw), Marsay, C. (Christopher), Maturilli, M. (Marion), Mech, M. (Mario), Morris, S. (Sara), Moser, M. (Manuel), Nicolaus, M. (Marcel), Ortega, P. (Paul), Osborn, J. (Jackson), Paetzold, F. (Falk), Perovich, D. K. (Donald K.), Petäjä, T. (Tuukka), Pilz, C. (Christian), Pirazzini, R. (Roberta), Posman, K. (Kevin), Powers, H. (Heath), Pratt, K. A. (Kerri A.), Preusser, A. (Andreas), Quelever, L. (Lauriane), Radenz, M. (Martin), Rabe, B. (Benjamin), Rinke, A. (Annette), Sachs, T. (Torsten), Schulz, A. (Alexander), Siebert, H. (Holger), Silva, T. (Tercio), Solomon, A. (Amy), Sommerfeld, A. (Anja), Spreen, G. (Gunnar), Stephens, M. (Mark), Stohl, A. (Andreas), Svensson, G. (Gunilla), Uin, J. (Janek), Viegas, J. (Juarez), Voigt, C. (Christiane), von der Gathen, P. (Peter), Wehner, B. (Birgit), Welker, J. M. (Jeffrey M.), Wendisch, M. (Manfred), Werner, M. (Martin), Xie, Z. (ZhouQing), and Yue, F. (Fange)

Abstract

With the Arctic rapidly changing, the needs to observe, understand, and model the changes are essential. To support these needs, an annual cycle of observations of atmospheric properties, processes, and interactions were made while drifting with the sea ice across the central Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition from October 2019 to September 2020. An international team designed and implemented the comprehensive program to document and characterize all aspects of the Arctic atmospheric system in unprecedented detail, using a variety of approaches, and across multiple scales. These measurements were coordinated with other observational teams to explore crosscutting and coupled interactions with the Arctic Ocean, sea ice, and ecosystem through a variety of physical and biogeochemical processes. This overview outlines the breadth and complexity of the atmospheric research program, which was organized into 4 subgroups: atmospheric state, clouds and precipitation, gases and aerosols, and energy budgets. Atmospheric variability over the annual cycle revealed important influences from a persistent large-scale winter circulation pattern, leading to some storms with pressure and winds that were outside the interquartile range of past conditions suggested by long-term reanalysis. Similarly, the MOSAiC location was warmer and wetter in summer than the reanalysis climatology, in part due to its close proximity to the sea ice edge. The comprehensiveness of the observational program for characterizing and analyzing atmospheric phenomena is demonstrated via a winter case study examining air mass transitions and a summer case study examining vertical atmospheric evolution. Overall, the MOSAiC atmospheric program successfully met its objectives and was the most comprehensive atmospheric measurement program to date conducted over the Arctic sea ice. The obtained data will support a broad range of coupled

Published
2022

23. Physical properties of sea ice cores from site MCS_FYI measured on legs 1 to 3 of the MOSAiC expedition

Author

Angelopoulos, M., Abrahamsson, K., Bauch, D., Bowman, J., Castellani, G., Creamean, J., Damm, E., Divine, D., Dumitrascu, A., Eggers, L., Fong, A., Fons, S., Gradinger, R., Granskog, M., Grosse, J., Haapala, J., Haas, C., Hoppe, C., Høyland, K., Immerz, A., Kolabutin, N., Krumpen, T., Lei, R., Marsay, C., Maus, S., Nicolaus, M., Nubom, A., Oggier, M., Olsen, L., Rember, R., Ren, J., Rinke, A., Sachs, T., Sheikin, I., Shimanchuk, E., Simões Pereira, P., Spahic, S., Stefels, J., Stephens, M., Torres-Valdés, S., Torstensson, A., Ulfsbo, A., Verdugo, J., Wang, L., Wischnewski, L., and Zhan, L.

Abstract

We present sea ice temperature and salinity data from first-year ice (FYI) and second-year ice (SYI) relevant to the temporal development of sea ice permeability and brine drainage efficiency from the early growth phase in October 2019 to the onset of spring warming in May 2020. Our dataset was collected in the central Arctic Ocean during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) Expedition in 2019 to 2020. MOSAiC was an international transpolar drift expedition in which the German icebreaker RV Polarstern anchored into an ice floe to gain new insights into Arctic climate over a full annual cycle. In October 2019, RV Polarstern moored to an ice floe in the Siberian sector of the Arctic at 85 degrees north and 137 degrees east to begin the drift towards the North Pole and the Fram Strait via the Transpolar Drift Stream. The data presented here were collected during the first three legs of the expedition, so all the coring activities took place on the same floe. The end dates of legs 1, 2, and 3 were 13 December, 24 February, and 4 June, respectively. The dataset contributed to a baseline study entitled, Deciphering the properties of different Arctic ice types during the growth phase of the MOSAiC floes: Implications for future studies. The study highlights downward directed gas pathways in FYI and SYI by inferring sea ice permeability and potential brine release from several time series of temperature and salinity measurements. The physical properties presented in this paper lay the foundation for subsequent analyses on actual gas contents measured in the ice cores, as well as air-ice and ice-ocean gas fluxes. Sea ice cores were collected with a Kovacs Mark II 9 cm diameter corer. To measure ice temperatures, about 4.5 cm deep holes were drilled into the core (intervals varied by site and leg) . The temperatures were measured by a digital thermometer within minutes after the cores were retrieved. The ice cores were placed into pre-labelled plastic sleeves sealed at the bottom end. The ice cores were transported to RV Polarstern and stored in a -20 degrees Celsius freezer. Each of the cores was sub-sampled, melted at room temperature, and processed for salinity within one or two days. The practical salinity was estimated by measuring the electrical conductivity and temperature of the melted samples using a WTW Cond 3151 salinometer equipped with a Tetra-Con 325 four-electrode conductivity cell. The practical salinity represents the the salinity estimated from the electrical conductivity of the solution. The dataset also contains derived variables, including sea ice density, brine volume fraction, and the Rayleigh number.

Published
2022

24. Physical properties of sea ice cores from site MCS-SYI measured on legs 1 to 3 of the MOSAiC expedition

Author

Angelopoulos, M., Abrahamsson, K., Bauch, D., Bowman, J., Castellani, G., Creamean, J., Damm, E., Divine, D., Dumitrascu, A., Eggers, L., Fong, A., Fons, S., Gradinger, R., Granskog, M., Grosse, J., Haapala, J., Haas, C., Hoppe, C., Høyland, K., Immerz, A., Kolabutin, N., Krumpen, T., Lei, R., Marsay, C., Maus, S., Nicolaus, M., Nubom, A., Oggier, M., Olsen, L., Rember, R., Ren, J., Rinke, A., Sachs, T., Sheikin, I., Shimanchuk, E., Simões Pereira, P., Spahic, S., Stefels, J., Stephens, M., Torres-Valdés, S., Torstensson, A., Ulfsbo, A., Verdugo, J., Wang, L., Wischnewski, L., and Zhan, L.

Abstract

We present sea ice temperature and salinity data from first-year ice (FYI) and second-year ice (SYI) relevant to the temporal development of sea ice permeability and brine drainage efficiency from the early growth phase in October 2019 to the onset of spring warming in May 2020. Our dataset was collected in the central Arctic Ocean during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) Expedition in 2019 to 2020. MOSAiC was an international transpolar drift expedition in which the German icebreaker RV Polarstern anchored into an ice floe to gain new insights into Arctic climate over a full annual cycle. In October 2019, RV Polarstern moored to an ice floe in the Siberian sector of the Arctic at 85 degrees north and 137 degrees east to begin the drift towards the North Pole and the Fram Strait via the Transpolar Drift Stream. The data presented here were collected during the first three legs of the expedition, so all the coring activities took place on the same floe. The end dates of legs 1, 2, and 3 were 13 December, 24 February, and 4 June, respectively. The dataset contributed to a baseline study entitled, Deciphering the properties of different Arctic ice types during the growth phase of the MOSAiC floes: Implications for future studies. The study highlights downward directed gas pathways in FYI and SYI by inferring sea ice permeability and potential brine release from several time series of temperature and salinity measurements. The physical properties presented in this paper lay the foundation for subsequent analyses on actual gas contents measured in the ice cores, as well as air-ice and ice-ocean gas fluxes. Sea ice cores were collected with a Kovacs Mark II 9 cm diameter corer. To measure ice temperatures, about 4.5 cm deep holes were drilled into the core (intervals varied by site and leg) . The temperatures were measured by a digital thermometer within minutes after the cores were retrieved. The ice cores were placed into pre-labelled plastic sleeves sealed at the bottom end. The ice cores were transported to RV Polarstern and stored in a -20 degrees Celsius freezer. Each of the cores was sub-sampled, melted at room temperature, and processed for salinity within one or two days. The practical salinity was estimated by measuring the electrical conductivity and temperature of the melted samples using a WTW Cond 3151 salinometer equipped with a Tetra-Con 325 four-electrode conductivity cell. The practical salinity represents the the salinity estimated from the electrical conductivity of the solution. The dataset also contains derived variables, including sea ice density, brine volume fraction, and the Rayleigh number.

Published
2022

25. Physical properties of sea ice cores for biogeochemistry studies measured on legs 1 to 3 of the MOSAiC expedition

Author

Angelopoulos, M., Damm, E., Simões Pereira, P., Abrahamsson, K., Bauch, D., Bowman, J., Castellani, G., Creamean, J., Divine, D., Dumitrascu, A., Eggers, L., Fong, A., Fons, S., Gradinger, R., Granskog, M., Grosse, J., Haapala, J., Haas, C., Hoppe, C., Høyland, K., Immerz, A., Kolabutin, N., Krumpen, T., Lei, R., Marsay, C., Maus, S., Nicolaus, M., Nubom, A., Oggier, M., Olsen, L., Rember, R., Ren, J., Rinke, A., Sachs, T., Sheikin, I., Shimanchuk, E., Spahic, S., Stefels, J., Stephens, M., Torres-Valdés, S., Torstensson, A., Ulfsbo, A., Verdugo, J., Wang, L., Wischnewski, L., and Zhan, L.

Abstract

We present sea ice temperature and salinity data from first-year ice (FYI) and second-year ice (SYI) relevant to the temporal development of sea ice permeability and brine drainage efficiency from the early growth phase in October 2019 to the onset of spring warming in May 2020. Our dataset was collected in the central Arctic Ocean during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) Expedition in 2019 to 2020. MOSAiC was an international transpolar drift expedition in which the German icebreaker RV Polarstern anchored into an ice floe to gain new insights into Arctic climate over a full annual cycle. In October 2019, RV Polarstern moored to an ice floe in the Siberian sector of the Arctic at 85 degrees north and 137 degrees east to begin the drift towards the North Pole and the Fram Strait via the Transpolar Drift Stream. The data presented here were collected during the first three legs of the expedition, so all the coring activities took place on the same floe. The end dates of legs 1, 2, and 3 were 13 December, 24 February, and 4 June, respectively. The dataset contributed to a baseline study entitled, Deciphering the properties of different Arctic ice types during the growth phase of the MOSAiC floes: Implications for future studies. The study highlights downward directed gas pathways in FYI and SYI by inferring sea ice permeability and potential brine release from several time series of temperature and salinity measurements. The physical properties presented in this paper lay the foundation for subsequent analyses on actual gas contents measured in the ice cores, as well as air-ice and ice-ocean gas fluxes. Sea ice cores were collected with a Kovacs Mark II 9 cm diameter corer. To measure ice temperatures, about 4.5 cm deep holes were drilled into the core (intervals varied by site and leg) . The temperatures were measured by a digital thermometer within minutes after the cores were retrieved. The ice cores were placed into pre-labelled plastic sleeves sealed at the bottom end. The ice cores were transported to RV Polarstern and stored in a -20 degrees Celsius freezer. Each of the cores was sub-sampled, melted at room temperature, and processed for salinity within one or two days. The practical salinity was estimated by measuring the electrical conductivity and temperature of the melted samples using a WTW Cond 3151 salinometer equipped with a Tetra-Con 325 four-electrode conductivity cell. The practical salinity represents the the salinity estimated from the electrical conductivity of the solution. The dataset also contains derived variables, including sea ice density, brine volume fraction, and the Rayleigh number.

Published
2022

27. Net heterotrophy in High Arctic first-year and multi-year spring sea ice

Author

Campbell, Karley, primary, Lange, B. A., additional, Landy, J. C., additional, Katlein, C., additional, Nicolaus, M., additional, Anhaus, P., additional, Matero, I., additional, Gradinger, R., additional, Charette, J., additional, Duerksen, S., additional, Tremblay, P., additional, Rysgaard, S., additional, Tranter, M., additional, Haas, C., additional, and Michel, C., additional

Published
2022
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33. Modeling silicate–nitrate–ammonium co-limitation of algal growth and the importance of bacterial remineralization based on an experimental Arctic coastal spring bloom culture study

Author

Vonnahme, T.R., Leroy, M., Thoms, S., van Oevelen, D., Harvey, H.R., Kristiansen, S., Gradinger, R., Dietrich, U., Völker, C., Vonnahme, T.R., Leroy, M., Thoms, S., van Oevelen, D., Harvey, H.R., Kristiansen, S., Gradinger, R., Dietrich, U., and Völker, C.

Abstract

Arctic coastal ecosystems are rapidly changing due to climate warming. This makes modeling their productivity crucially important to better understand future changes. System primary production in these systems is highest during the pronounced spring bloom, typically dominated by diatoms. Eventually the spring blooms terminate due to silicon or nitrogen limitation. Bacteria can play an important role for extending bloom duration and total CO2 fixation through ammonium regeneration. Current ecosystem models often simplify the effects of nutrient co-limitations on algal physiology and cellular ratios and simplify nutrient regeneration. These simplifications may lead to underestimations of primary production. Detailed biochemistry- and cell-based models can represent these dynamics but are difficult to tune in the environment. We performed a cultivation experiment that showed typical spring bloom dynamics, such as extended algal growth via bacterial ammonium remineralization, reduced algal growth and inhibited chlorophyll synthesis under silicate limitation, and gradually reduced nitrogen assimilation and chlorophyll synthesis under nitrogen limitation. We developed a simplified dynamic model to represent these processes. Overall, model complexity in terms of the number of parameters is comparable to the phytoplankton growth and nutrient biogeochemistry formulations in common ecosystem models used in the Arctic while improving the representation of nutrient-co-limitation-related processes. Such model enhancements that now incorporate increased nutrient inputs and higher mineralization rates in a warmer climate will improve future predictions in this vulnerable system.

Published
2021

34. Ice-algal carbon supports harp and ringed seal diets in the European Arctic: evidence from fatty acid and stable isotope markers

Author

Kunisch, EH, Graeve, Martin, Gradinger, R, Haug, T, Kovacs, KM, Lydersen, C, Varpe, Ø, Bluhm, BA, Kunisch, EH, Graeve, Martin, Gradinger, R, Haug, T, Kovacs, KM, Lydersen, C, Varpe, Ø, and Bluhm, BA

Abstract

Sea-ice declines in the European Arctic have led to substantial changes in marine food webs. To better understand the biological implications of these changes, we quantified the contributions of ice-associated and pelagic carbon sources to the diets of Arctic harp and ringed seals using compound-specific stable isotope ratios of fatty acids in specific primary producer biomarkers derived from sea-ice algae and phytoplankton. Comparison of fatty acid patterns between these 2 seal species indicated clear dietary separation, while the compound-specific stable isotope ratios of the same fatty acids showed partial overlap. These findings suggest that harp and ringed seals target different prey sources, yet their prey rely on ice and pelagic primary production in similar ways. From Bayesian stable isotope mixing models, we estimated that relative contributions of sympagic and pelagic carbon in seal blubber was an average of 69% and 31% for harp seals, and 72% and 28% for ringed seals, respectively. The similarity in the Bayesian estimations also indicates overlapping carbon sourcing by these 2 species. Our findings demonstrate that the seasonal ice-associated carbon pathway contributes substantially to the diets of both harp and ringed seals.

Published
2021

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