References of "Vancoppenolle, M"
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See detailChlorophyll- a in Antarctic Landfast Sea Ice: A First Synthesis of Historical Ice Core Data
Meiners, K. M.; Vancoppenolle, M.; Carnat, G. et al

in Journal of Geophysical Research. Oceans (2018), 123(11), 8444-8459

Abstract Historical sea‐ice core chlorophyll‐a (Chla) data are used to describe the seasonal, regional and vertical distribution of ice algal biomass in Antarctic landfast sea ice. The analyses are based ... [more ▼]

Abstract Historical sea‐ice core chlorophyll‐a (Chla) data are used to describe the seasonal, regional and vertical distribution of ice algal biomass in Antarctic landfast sea ice. The analyses are based on the Antarctic Fast Ice Algae Chlorophyll‐a dataset, a compilation of currently available sea‐ice Chla data from landfast sea‐ice cores collected at circum‐Antarctic nearshore locations between 1970 and 2015. Ice cores were typically sampled from thermodynamically grown first‐year ice and have thin snow depths (mean = 0.052 ± 0.097 m). The dataset comprises 888 ice cores, including 404 full vertical profile cores. Integrated ice algal Chla biomass (range: ‐2 – 219.9 mg m‐2, median = 4.4 mg m‐2, interquartile range = 9.9 mg m‐2) peaks in late spring and shows elevated levels in autumn. The seasonal Chla development is consistent with the current understanding of physical drivers of ice algal biomass, including the seasonal cycle of irradiance and surface temperatures driving landfast sea‐ice growth and melt. Landfast ice regions with reported platelet‐ice formation show maximum ice algal biomass. Ice algal communities in the lower‐most third of the ice cores dominate integrated Chla concentrations during most of the year, but internal and surface communities are important, particularly in winter. Through comparison of biomass estimates based on different sea‐ice sampling strategies, i.e., analysis of full cores versus bottom‐ice section sampling, we identify biases in common sampling approaches and provide recommendations for future survey programs: e.g., the need to sample fast ice over its entire thickness and to measure auxiliary physico‐chemical parameters. [less ▲]

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See detailMacro-nutrient concentrations in Antarctic pack ice: Overall patterns and overlooked processes
Fripiat, François ULiege; Meiners, K.M.; Vancoppenolle, M. et al

in Elementa: Science of the Anthropocene (2017), 5(13),

Antarctic pack ice is inhabited by a diverse and active microbial community reliant on nutrients for growth. Seeking patterns and overlooked processes, we performed a large-scale compilation of macro ... [more ▼]

Antarctic pack ice is inhabited by a diverse and active microbial community reliant on nutrients for growth. Seeking patterns and overlooked processes, we performed a large-scale compilation of macro-nutrient data (hereafter termed nutrients) in Antarctic pack ice (306 ice-cores collected from 19 research cruises). Dissolved inorganic nitrogen and silicic acid concentrations change with time, as expected from a seasonally productive ecosystem. In winter, salinity-normalized nitrate and silicic acid concentrations (C*) in sea ice are close to seawater concentrations (Cw), indicating little or no biological activity. In spring, nitrate and silicic acid concentrations become partially depleted with respect to seawater (C* < Cw), commensurate with the seasonal build-up of ice microalgae promoted by increased insolation. Stronger and earlier nitrate than silicic acid consumption suggests that a significant fraction of the primary productivity in sea ice is sustained by flagellates. By both consuming and producing ammonium and nitrite, the microbial community maintains these nutrients at relatively low concentrations in spring. With the decrease in insolation beginning in late summer, dissolved inorganic nitrogen and silicic acid concentrations increase, indicating imbalance between their production (increasing or unchanged) and consumption (decreasing) in sea ice. Unlike the depleted concentrations of both nitrate and silicic acid from spring to summer, phosphate accumulates in sea ice (C* > Cw). The phosphate excess could be explained by a greater allocation to phosphorus-rich biomolecules during ice algal blooms coupled with convective loss of excess dissolved nitrogen, preferential remineralization of phosphorus, and/or phosphate adsorption onto metal-organic complexes. Ammonium also appears to be efficiently adsorbed onto organic matter, with likely consequences to nitrogen mobility and availability. This dataset supports the view that the sea ice microbial community is highly efficient at processing nutrients but with a dynamic quite different from that in oceanic surface waters calling for focused future investigations. [less ▲]

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See detailBiogeochemical Impact of Snow Cover and Cyclonic Intrusions on the Winter Weddell Sea Ice Pack
Tison, J.-L.; Schwegmann, S.; Dieckmann, G. et al

in Journal of Geophysical Research. Oceans (2017), 122(12), 9548--9571

Sea ice is a dynamic biogeochemical reactor and a double interface actively interacting with both the atmosphere and the ocean. However, proper understanding of its annual impact on exchanges, and ... [more ▼]

Sea ice is a dynamic biogeochemical reactor and a double interface actively interacting with both the atmosphere and the ocean. However, proper understanding of its annual impact on exchanges, and therefore potentially on the climate, notably suffer from the paucity of autumnal and winter data sets. Here we present the results of physical and biogeochemical investigations on winter Antarctic pack ice in the Weddell Sea (R. V. Polarstern AWECS cruise, June–August 2013) which are compared with those from two similar studies conducted in the area in 1986 and 1992. The winter 2013 was characterized by a warm sea ice cover due to the combined effects of deep snow and frequent warm cyclones events penetrating southward from the open Southern Ocean. These conditions were favorable to high ice permeability and cyclic events of brine movements within the sea ice cover (brine tubes), favoring relatively high chlorophyll-a (Chl-a) concentrations. We discuss the timing of this algal activity showing that arguments can be presented in favor of continued activity during the winter due to the specific physical conditions. Large-scale sea ice model simulations also suggest a context of increasingly deep snow, warm ice, and large brine fractions across the three observational years, despite the fact that the model is forced with a snowfall climatology. This lends support to the claim that more severe Antarctic sea ice conditions, characterized by a longer ice season, thicker, and more concentrated ice are sufficient to increase the snow depth and, somehow counterintuitively, to warm the ice. [less ▲]

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See detailHighly productive, yet heterotrophic, and still pumping CO2 from the atmosphere: A land fast ice paradigm?
Delille, Bruno ULiege; Van der Linden, Fanny ULiege; Conte, L et al

Conference (2016, October 21)

The YROSIAE (Year Round survey of Ocean-Sea Ice-Air Exchanges) survey aimed to carry out a year-round survey of land-fast sea ice focusing on the study of sea ice physics and biogeochemistry. Ice cores ... [more ▼]

The YROSIAE (Year Round survey of Ocean-Sea Ice-Air Exchanges) survey aimed to carry out a year-round survey of land-fast sea ice focusing on the study of sea ice physics and biogeochemistry. Ice cores, sea water, brines material were collected at regular intervals about 1 km off cape Evans in McMurdo Sound, Antarctica, from November 2011 to December 2011 and from September 2012 to December 2012. Samples were processed to characterize both the vertical distribution and temporal changes of climate gases (CO2, DMS, CH4, N2O), CO2-related parameters (ice-air CO2 fluxes, dissolved inorganic carbon, total alkalinity and CaCO3 amount), physical parameters (salinity, temperature, and ice texture), biogeochemical parameters (macro-nutrients, particulate and dissolved organic carbon, δ13C, δ30Si and δ15N) and biological parameters (chlorophyll a, primary production within sea ice derived from O2:Ar and O2:N ratios…). Very high chlorophyll a abundance was observed at the bottom of the ice, a common feature of land fast ice in McMurdo Sound. During spring, chlorophyll a exhibited a significant increase suggesting high primary production. . However, at the same time, nutrients at the bottom of the ice increased significantly suggesting high remineralization and heterotrophy. In the middle of the ice column, evolution of dissolved inorganic carbon shown a succession of autotrophic and heterotrophic phases. However, the overall increase of DIC suggests that the ice interior was rather heterotroph. This was consistent with the increase in nutrients observed at the bottom of the ice. Such sea ice system should expel CO2. Yet, strong under saturation in CO2 in surface ice, and negative air-ice CO2 fluxes suggested that sea ice was taking up CO2 from the atmosphere. Meanwhile, measurements of N2O within the sea ice suggest that the ice was releasing N2O to the atmosphere as a result of high nitrification. On the whole land fast sea ice in McMurdo Sound appears as a puzzling ecosystem. It is able to support elevated growth of autotrophic organisms, but appears to be heterotrophic, yet pumping CO2 to the atmosphere but releasing other greenhouse gases. [less ▲]

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See detailContrasting Arctic and Antarctic sea ice temperatures
Vancoppenolle, M.; Raphael, M.; Rousset, C. et al

Conference (2016, April)

Sea ice temperature affects the sea ice growth rate, heat content, permeability and habitability for ice algae. Large-scale simulations with NEMO-LIM suggest large ice temperature contrasts between the ... [more ▼]

Sea ice temperature affects the sea ice growth rate, heat content, permeability and habitability for ice algae. Large-scale simulations with NEMO-LIM suggest large ice temperature contrasts between the Arctic and the Antarctic sea ice. First, Antarctic sea ice proves generally warmer than in the Arctic, in particular during winter, where differences reach up to ∼10◦C. Second, the seasonality of temperature is different among the two hemispheres: Antarctic ice temperatures are 2-3◦C higher in spring than they are in fall, whereas the opposite is true in the Arctic. These two key differences are supported by the available ice core and mass balance buoys temperature observations, and can be attributed to differences in air temperature and snow depth. As a result, the ice is found to be habitable and permeable over much larger areas and much earlier in late spring in the Antarctic as compared with the Arctic, which consequences on biogeochemical exchanges in the sea ice zone remain to be evaluated. [less ▲]

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See detailAssessing the O2 budget under sea ice: An experimental and modelling approach
Moreau, S.; Kaartokallio, H.; Vancoppenolle, M. et al

in Elementa: Science of the Anthropocene (2015), 3(000080),

The objective of this study was to assess the O2 budget in the water under sea ice combining observations and modelling. Modelling was used to discriminate between physical processes, gas-specific ... [more ▼]

The objective of this study was to assess the O2 budget in the water under sea ice combining observations and modelling. Modelling was used to discriminate between physical processes, gas-specific transport (i.e., ice-atmosphere gas fluxes and gas bubble buoyancy) and bacterial respiration (BR) and to constrain bacterial growth efficiency (BGE). A module describing the changes of the under-ice water properties, due to brine rejection and temperature-dependent BR, was implemented in the one-dimensional halo-thermodynamic sea ice model LIM1D. Our results show that BR was the dominant biogeochemical driver of O2 concentration in the water under ice (in a system without primary producers), followed by gas specific transport. The model suggests that the actual contribution of BR and gas specific transport to the change in seawater O2 concentration was 37% during ice growth and 48% during melt. BGE in the water under sea ice, as retrieved from the simulated O2 budget, was found to be between 0.4 and 0.5, which is in line with published BGE values for cold marine waters. Given the importance of BR to seawater O2 in the present study, it can be assumed that bacteria contribute substantially to organic matter consumption and gas fluxes in ice-covered polar oceans. In addition, we propose a parameterization of polar marine bacterial respiration, based on the strong temperature dependence of bacterial respiration and the high growth efficiency observed here, for further biogeochemical ocean modelling applications, such as regional or large-scale Earth System models [less ▲]

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See detailAir-sea ice gases exchange: update of recent findings, outcomes from sea ice models, caveats and open questions
Delille, Bruno ULiege; Zhou, Jiayun; Kotovitch, Marie ULiege et al

Conference (2015, September 21)

There are growing evidences that sea ice exchanges climate gases with the atmosphere. We will rapidly present a state of the art of current large scale assessment of spring and summer uptake of ... [more ▼]

There are growing evidences that sea ice exchanges climate gases with the atmosphere. We will rapidly present a state of the art of current large scale assessment of spring and summer uptake of atmospheric CO2. We will challenge these assessments with 1) new evidence of significant winter CO2 release for winter experiments 2) new finding of the role of bubbles formation and transport within sea ice and 3) impurities expulsion derived from combined artificial ice experiment and modelling. Finally, comparison of air-ice fluxes derived from automated chamber and micrometeorological method and, mechanistic and box models show significant discrepancies that suggest that the contribution of sea ice to the air-ocean fluxes of CO2 remain an open question. We will also highlight that sea ice contribute to the fluxes of other gases as CH4 ,N2O and DMS [less ▲]

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See detailDetermination of air‐sea ice transfer coefficient for CO2: Significant contribution of gas bubble transport during sea ice growth
Kotovitch, Marie ULiege; Moreau, S.; Zhou, Jiayun et al

Poster (2015, September)

Air‐ice CO2 fluxes were measured continuously from the freezing of a young sea‐ice cover until its decay. Cooling seawater was as a sink for atmospheric CO2 but asthe ice crystalsformed,sea ice shifted to ... [more ▼]

Air‐ice CO2 fluxes were measured continuously from the freezing of a young sea‐ice cover until its decay. Cooling seawater was as a sink for atmospheric CO2 but asthe ice crystalsformed,sea ice shifted to a source releasing CO2 to the atmosphere throughout the whole ice growth. Atmospheric warming initiated the decay, re‐shifting sea‐ice to a CO2 sink. Combining these CO2 fluxes with the partial pressure of CO2 within sea ice, we determined gas transfer coefficients for CO2 at air‐ice interface for growth and decay. We hypothesize that this difference originates from the transport of gas bubbles during ice growth, while only diffusion occurs during ice melt. In parallel, we used a 1D biogeochemical model to mimic the observed CO2 fluxes. The formation of gas bubbles was crucial to reproduce fluxes during ice growth where gas bubbles may account for up to 92 % of the upward CO2 fluxes. [less ▲]

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See detailSea ice in the global biogeochemical cycles: How much do we care?
Vancoppenolle, M.; Moreau, S.; Bopp, L. et al

Conference (2015, September)

Large changes in the state and seasonality of sea ice are expected for this century in both hemispheres. The impact of these changes on marine biogeochemical cycles and ecosystems is difficult to predict ... [more ▼]

Large changes in the state and seasonality of sea ice are expected for this century in both hemispheres. The impact of these changes on marine biogeochemical cycles and ecosystems is difficult to predict. Will the polar oceans be more or less biologically productive? Will they take up more or less carbon? At this stage, the answers to these key questions are not obvious. Marine biogeochemical cycles in the sea ice zone are characterized by specific processes that have been unravelled over the last 20 years or so. They involve active biological and chemical processes within the sea ice, the modulation of heat and gas exchanges by the ice cover; and the impact of growing and melting sea ice on the water column stratification and vertical exchanges in the water. To understand how sea ice influences marine biogeochemical cycles, the sea ice biogeochemical community focuses on: (i) the synthesis of existing data and the interpretation of robust large-scale patterns; (ii) the introduction of new representations of sea ice processes into large-scale models of the Earth System and the study of their impact; (iii) the evaluation of existing observation methods and the development of new ones. In this talk, I will review and synthesize recent research activities in these lines of thought. [less ▲]

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See detailDrivers of inorganic carbon dynamics in first-year sea ice: A model study
Moreau, S.; Vancoppenolle, M.; Delille, Bruno ULiege et al

Conference (2015, May 16)

Sea ice is an active source or a sink for carbon dioxide (CO2), although to what extent is not clear. Here, we analyze CO2 dynamics within sea ice using a one-dimensional halo-thermodynamic sea ice model ... [more ▼]

Sea ice is an active source or a sink for carbon dioxide (CO2), although to what extent is not clear. Here, we analyze CO2 dynamics within sea ice using a one-dimensional halo-thermodynamic sea ice model including gas physics and carbon biogeochemistry. The ice-ocean fluxes, and vertical transport, of total dissolved inorganic carbon (DIC) and total alkalinity (TA) are represented using fluid transport equations. Carbonate chemistry, the consumption and release of CO2 by primary production and respiration, the precipitation and dissolution of ikaite (CaCO3•6H2O) and ice-air CO2 fluxes, are also included. The model is evaluated using observations from a 6-month field study at Point Barrow, Alaska and an ice-tank experiment. At Barrow, results show that the DIC budget is mainly driven by physical processes, wheras brine-air CO2 fluxes, ikaite formation, and net primary production, are secondary factors. In terms of ice-atmosphere CO 2 exchanges, sea ice is a net CO2 source and sink in winter and summer, respectively. The formulation of the ice-atmosphere CO2 flux impacts the simulated near-surface CO2 partial pressure (pCO2), but not the DIC budget. Because the simulated ice-atmosphere CO2 fluxes are limited by DIC stocks, and therefore < 2 mmol m-2 day-1, we argue that the observed much larger CO2 fluxes from eddy covariance retrievals cannot be explained by a sea ice direct source and must involve other processes or other sources of CO2. Finally, the simulations suggest that near surface TA/DIC ratios of 2, sometimes used as an indicator of calcification, would rather suggest outgassing. [less ▲]

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See detailThe role of sea ice in the carbon cycle of Polar Seas: 1D to 3D modelling
Moreau, S.; Vancoppenolle, M.; Delille, Bruno ULiege et al

Poster (2015, May)

Sea ice participates actively in the biogeochemical cycle of carbon of Polar Oceans, yet to which extent is not clear. We investigated the processes that govern sea ice carbon dy- namics in Polar Regions ... [more ▼]

Sea ice participates actively in the biogeochemical cycle of carbon of Polar Oceans, yet to which extent is not clear. We investigated the processes that govern sea ice carbon dy- namics in Polar Regions through 1D to 3D modelling developments. First, we constrained all major physical and biogeochemical processes with respect to CO2 dynamics (carbon- ate chemistry, biological activity, ikaite (CaCO3•6H2O) precipitation and dissolution and ocean-ice-air CO2 fluxes) in a one-dimensional sea ice model. According to our model, the CO2 budget is driven by the CO2 uptake during ice growth and release by brine drainage, whereas other processes such as brine-air CO2 fluxes, despite significant, are secondary. Subsequently, based on these preliminary conclusions, we evaluated the role of sea ice in the carbon dynamics of Polar Oceans by using an ocean-ice coupled Global Earth System Model. Carbon dynamics (e.g. ocean-atmosphere CO2 fluxes) are driven by the contribution of sea ice growth regions in the Arctic Ocean (mainly the Siberian coast) and sea ice melt regions in the Southern Ocean (off the coast of Antarctica). In addition, the production of deep waters is low in the Arctic Ocean but significant in the Southern Ocean. Therefore, sea ice only contributes to the deep water export of carbon in the Southern Ocean. The role of sea ice in the biogeochemical cycle of carbon is significant and its representation by Global Earth System Models should be improved. [less ▲]

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See detailThe role of sea ice in the carbon cycle of Polar Seas: 1D to 3D modelling
Moreau, S.; Vancoppenolle, M.; Delille, Bruno ULiege et al

Poster (2015, March)

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See detailYear Round survey of Ocean-Sea Ice-Air Exchanges – the YROSIAE survey
Delille, Bruno ULiege; Haskell, T.; Champenois, Willy ULiege et al

Conference (2014, March)

YROSIAE survey aimed to carry out a year-round survey of land-fast sea ice focusing on the study of sea ice physics and biogeochemistry in order to a) better understand and budget exchanges of energy and ... [more ▼]

YROSIAE survey aimed to carry out a year-round survey of land-fast sea ice focusing on the study of sea ice physics and biogeochemistry in order to a) better understand and budget exchanges of energy and matter across the ocean-sea ice-atmosphere interfaces during sea ice growth and decay and b) quantify their potential impact on fluxes of climate gases (CO2, DMS, CH4, N2O) to the atmosphere and on carbon and macro- nutrients and micro-nutrients export to the ocean. Ice cores, sea water, brines and exported material were collected at regular intervals about 1 km off cape Evans from November 2011 to December 2011 and from September 2012 to December 2012 in trace-metal clean conditions. Samples are processed to characterize both the vertical distribution and temporal changes of climate gases (CO2, DMS, CH4, N2O), CO2-related parameters (dissolved inorganic carbon, total alkalinity and CaCO3 amount), physical parameters (salinity, temperature, texture, 18O), biogeochemical parameters (macro-nutrients, particulate and dissolved organic carbon, δ13C, δ30Si and δ15N, micro-nutrients - including iron) and biological parameters ( chlorophyll a, primary production within sea ice derived from O2:Ar and O2:N ratios, autotrophic species determination, bacterial cell counts a.s.o.). In addition, we deployed a micro-meterological tower and automatic chambers to measure air-ice CO2 fluxes. Continuous measurements of ice temperature and ice accretion or melting, both at the ice-ocean and the ice-atmosphere interfaces were provided by an “Ice-T” ice mass balance buoy. Sediment traps collected particles below the ice between 10 and 70 m, while dust collectors provided a record of a full suite of trace metal and dust at different levels above the ground. We will present the aims, overall approach and sampling strategy of the YROSIAE survey. In addition we will also discuss CO2 dynamics within the ice and present temporal air-ice CO2 fluxes over the year. We will provide a first budget of air-ice CO2 fluxes during ice growth for Antarctica sea ice and discuss the impact of the snow cover on air-ice CO2 fluxes. [less ▲]

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See detailModelling argon dynamics in first-year sea ice
Moreau, S.; Vancoppenolle, M; Zhou, Jiayun ULiege et al

in Ocean Modelling (2014), 73

Abstract: Focusing on physical processes, we aim at constraining the dynamics of argon (Ar), a biogeochemically inert gas, within first year sea ice, using observation data and a one-dimensional halo ... [more ▼]

Abstract: Focusing on physical processes, we aim at constraining the dynamics of argon (Ar), a biogeochemically inert gas, within first year sea ice, using observation data and a one-dimensional halo-thermodynamic sea ice model, including parameterization of gas physics. The incorporation and transport of dissolved Ar within sea ice and its rejection via gas-enriched brine drainage to the ocean, are modeled following fluid transport equations through sea ice. Gas bubbles nucleate within sea ice when Ar is above saturation and when the total partial pressure of all three major atmospheric gases (N2, O2 and Ar) is above the brine hydrostatic pressure. The uplift of gas bubbles due to buoyancy is allowed when the brine network is connected with a brine volume above a given threshold. Ice-atmosphere Ar fluxes are formulated as a diffusive process proportional to the differential partial pressure of Ar between brine inclusions and the atmosphere. Two simulations corresponding to two case studies that took place at Point Barrow (Alaska, 2009) and during an ice-tank experiment (INTERICE IV, Hamburg, Germany, 2009) are presented. Basal entrapment and vertical transport due to brine motion enable a qualitatively sound representation of the vertical profile of the total Ar (i.e. the Ar dissolved in brine inclusions and contained in gas bubbles; TAr). Sensitivity analyses suggest that gas bubble nucleation and rise are of most importance to describe gas dynamics within sea ice. Ice-atmosphere Ar fluxes and the associated parameters do not drastically change the simulated TAr. Ar dynamics are dominated by uptake, transport by brine dynamics and bubble nucleation in winter and early spring; and by an intense and rapid release of gas bubbles to the atmosphere in spring. Important physical processes driving gas dynamics in sea ice are identified, pointing to the need for further field and experimental studies. [less ▲]

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See detailSouthern Ocean CO2 sink: The contribution of the sea ice
Delille, Bruno ULiege; Vancoppenolle, M; Geilfus, N.-X. et al

in Journal of Geophysical Research. Oceans (2014), 119

We report first direct measurements of the partial pressure of CO2 (pCO2) within Antarctic pack sea ice brines and related CO2 fluxes across the air-ice interface. From late winter to summer, brines ... [more ▼]

We report first direct measurements of the partial pressure of CO2 (pCO2) within Antarctic pack sea ice brines and related CO2 fluxes across the air-ice interface. From late winter to summer, brines encased in the ice change from a CO2 large over-saturation, relative to the atmosphere, to a marked under-saturation while the underlying oceanic waters remains slightly oversaturated. The decrease from winter to summer of pCO2 in the brines is driven by dilution with melting ice, dissolution of carbonate minerals crystals and net primary production. As the ice warms, its permeability increases, allowing CO2 transfer at the air-sea ice interface. The sea ice changes from a transient source to a sink for atmospheric CO2. We upscale these observations to the whole Antarctic sea-icesea ice cover using the NEMO-LIM3 large-scale sea ice-ocean, and provide first estimates of spring and summer CO2 uptake from the atmosphere by Antarctic sea ice. Over the spring-summer period, the Antarctic sea-icesea ice cover is a net sink of atmospheric CO2 of 0.029 PgC, about 58% of the estimated annual uptake from the Southern Ocean. Sea ice then contributes significantly to the sink of CO2 of the Southern Ocean. [less ▲]

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See detailRole of sea ice in global biogeochemical cycles: Emerging views and challenges
Vancoppenolle, M; Meiners, K.M.; Michel, C. et al

in Quaternary Science Reviews (2013), 79

Observations from the last decade suggest an important role of sea ice in the global biogeochemical cycles, promoted by (i) active biological and chemical processes within the sea ice; (ii) fluid and gas ... [more ▼]

Observations from the last decade suggest an important role of sea ice in the global biogeochemical cycles, promoted by (i) active biological and chemical processes within the sea ice; (ii) fluid and gas exchanges at the sea ice interface through an often permeable sea ice cover; and (iii) tight physical, biological and chemical interactions between the sea ice, the ocean and the atmosphere. Photosynthetic micro-organisms in sea ice thrive in liquid brine inclusions encased in a pure ice matrix, where they find suitable light and nutrient levels. They extend the production season, provide a winter and early spring food source, and contribute to organic carbon export to depth. Under-ice and ice edge phytoplankton blooms occur when ice retreats, favoured by increasing light, stratification, and by the release of material into the water column. In particular, the release of iron – highly concentrated in sea ice – could have large effects in the iron-limited Southern Ocean. The export of inorganic carbon transport by brine sinking below the mixed layer, calcium carbonate precipitation in sea ice, as well as active iceatmosphere carbon dioxide (CO2) fluxes, could play a central role in the marine carbon cycle. Sea ice processes could also significantly contribute to the sulphur cycle through the large production by ice algae of dimethylsulfoniopropionate (DMSP), the precursor of sulfate aerosols, which as cloud condensation nuclei have a potential cooling effect on the planet. Finally, the sea ice zone supports significant ocean-atmosphere methane (CH4) fluxes, while saline ice surfaces activate springtime atmospheric bromine chemistry, setting ground for tropospheric ozone depletion events observed near both poles. All these mechanisms are generally known, but neither precisely understood nor quantified at large scales. As polar regions are rapidly changing, understanding the large-scale polar marine biogeochemical processes and their future evolution is of high priority. Earth system models should in this context prove essential, but they currently represent sea ice as biologically and chemically inert. Paleoclimatic proxies are also relevant, in particular the sea ice proxies, inferring past sea ice conditions from glacial and marine sediment core records and providing analogs for future changes. Being highly constrained by marine biogeochemistry, sea ice proxies would not only contribute to but also benefit from a better understanding of polar marine biogeochemical cycles. [less ▲]

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See detailPhysical and biogeochemical properties in landfast sea ice (Barrow, Alaska): insights on brine and gas dynamics across seasons
Zhou, Jiayun ULiege; Delille, Bruno ULiege; Eicken, H. et al

in Journal of Geophysical Research (2013), 118(6), 3172-3189

The impacts of the seasonal evolution of sea-ice physical properties on ice-ocean biogeochemical exchanges were investigated in landfast ice at Barrow (Alaska) from January through June 2009. Three stages ... [more ▼]

The impacts of the seasonal evolution of sea-ice physical properties on ice-ocean biogeochemical exchanges were investigated in landfast ice at Barrow (Alaska) from January through June 2009. Three stages of brine dynamics across the annual cycle have been identified based on brine salinity, brine volume fraction and porous medium Rayleigh number [less ▲]

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See detailModeling argon dynamics in first-year sea ice
Moreau, S.; Vancoppenolle, M.; Tison, J.-L. et al

Poster (2012, July)

Detailed reference viewed: 17 (1 ULiège)
See detailOverview of CO2 dynamics within sea ice
Delille, Bruno ULiege; Geilfus, Nicolas-Xavier ULiege; Vancoppenolle, M. et al

Conference (2011)

Detailed reference viewed: 18 (5 ULiège)
See detailOceanic CO2 sink: the contribution of the marine cryosphere
Delille, Bruno ULiege; Vancoppenolle, M.; Tilbrook, B. et al

Conference (2010)

Detailed reference viewed: 11 (0 ULiège)