Effect of melting Antarctic sea ice on the fate of microbial communities studied in microcosms

Lannuzel, Delphine; Schoemann, Véronique; Dumont, Isabelle; Jong, Jeroen de; Tison, Jean-Louis; Delille, Bruno; Becquevort, Sylvie

doi:10.1007/s00300-013-1368-7

Cited by 31 publications

(25 citation statements)

References 62 publications

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“…Boyd et al (2012) showed that iron flux from melting sea ice is one of the largest iron sources in some regions. Previous studies suggested that iron from melting ice contributed 70-90 % of the total iron supply to surface waters in the East Antarctic, the Weddell Sea, and the Ross Sea during the melting period (Lannuzel et al, 2007(Lannuzel et al, , 2008de Jong et al, 2013). Simulated iron inputs from melting ice in our simulations are generally less than these observational estimates.…”

Section: Iron Sources To Sea Icecontrasting

confidence: 50%

“…Figure 2a shows clear changes of the total iron input to seawater in the Southern Ocean. Previous studies reported that melting ice released 0.30-0.70 µmol Fe m −2 day −1 of iron to surface waters in the East Antarctic, the Weddell Sea, and the Ross Sea (Lannuzel et al, 2007(Lannuzel et al, , 2008; de Jong et al, 2013). Simulated iron fluxes from sea ice to ocean are often less than 1 µmol Fe m −2 month −1 in the Southern Ocean in our simulations, except in the Bellingshausen Sea (> 30 µmol Fe m −2 month −1 ).…”

Section: Impacts Of Sea Ice On the Iron Cycle And Marine Ecosystemsmentioning

confidence: 99%

“…The role of sea ice in nutrient cycling has been the subject of an increasing number of studies over the past decade (Aguilar-Islas et al, 2008;de Jong et al, 2013;Lancelot et al, 2009;Lannuzel et al, 2007Lannuzel et al, , 2008Lannuzel et al, , 2011Lannuzel et al, , 2013Lannuzel et al, , 2014Measures, 1999;van der Merwe et al, 2009van der Merwe et al, , 2011b. Observational data on iron concentrations in sea ice and the surrounding seawater are scarce due to harsh conditions and difficulty in making measurements.…”

Section: Introductionmentioning

confidence: 99%

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Impact of sea ice on the marine iron cycle and phytoplankton productivity

et al. 2014

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Abstract. Iron is a key nutrient for phytoplankton growth in the surface ocean. At high latitudes, the iron cycle is closely related to the dynamics of sea ice. In recent decades, Arctic sea ice cover has been declining rapidly and Antarctic sea ice has exhibited large regional trends. A significant reduction of sea ice in both hemispheres is projected in future climate scenarios. In order to adequately study the effect of sea ice on the polar iron cycle, sea ice bearing iron was incorporated in the Community Earth System Model (CESM). Sea ice acts as a reservoir for iron during winter and releases the trace metal to the surface ocean in spring and summer. Simulated iron concentrations in sea ice generally agree with observations in regions where iron concentrations are relatively low. The maximum iron concentrations simulated in Arctic and Antarctic sea ice are much lower than observed, which is likely due to underestimation of iron inputs to sea ice or missing mechanisms. The largest iron source to sea ice is suspended sediments, contributing fluxes of iron of 2.2 × 10 8 mol Fe month −1 in the Arctic and 4

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Section: Iron Sources To Sea Icecontrasting

confidence: 50%

Section: Impacts Of Sea Ice On the Iron Cycle And Marine Ecosystemsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impact of sea ice on the marine iron cycle and phytoplankton productivity

et al. 2014

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“…Although our DFe concentrations are relatively low compared to other studies collected in winter, spring and summer (Westerlund and Öhman, 1991;de Jong et al, 1998;Lannuzel et al, 2007Lannuzel et al, , 2008Lannuzel et al, , 2013Lannuzel et al, , 2014avan der Merwe et al, 2009van der Merwe et al, , 2011a, our study provides the first evidence that sea ice begins to accumulate DFe as soon as it forms and grows in late autumn and early winter. Following this initial physico-chemical enrichment, DFe concentrations in sea ice subsequently increase as the ice ages through the season, likely due to biogenic processes (Lizotte, 2003;Thomas et al, 2010) or detrital remineralization processes, e.g., transformation of PFe into DFe.…”

Section: Incorporation Of Dissolved Constituents: Conservative and Nomentioning

confidence: 38%

Incorporation of iron and organic matter into young Antarctic sea ice during its initial growth stages

Janssens

Meiners

Tison

et al. 2016

Elementa: Science of the Anthropocene

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This study reports concentrations of iron (Fe) and organic matter in young Antarctic pack ice and during its initial growth stages in situ. Although the importance of sea ice as an Fe reservoir for oceanic waters of the Southern Ocean has been clearly established, the processes leading to the enrichment of Fe in sea ice have yet to be investigated and quantified. We conducted two in situ sea-ice growth experiments during a winter cruise in the Weddell Sea. Our aim was to improve the understanding of the processes responsible for the accumulation of dissolved Fe (DFe) and particulate Fe (PFe) in sea ice, and of particulate organic carbon and nitrogen, dissolved organic carbon, extracellular polymeric substances, inorganic macro-nutrients (silicic acid, nitrate and nitrite, phosphate and ammonium), chlorophyll a and bacteria. Enrichment indices, calculated for natural young ice and ice newly formed in situ, indicate that during Antarctic winter all of the measured forms of particulate matter were enriched in sea ice compared to underlying seawater, and that enrichment started from the initial stages of sea-ice formation. Some dissolved material (DFe and ammonium) was also enriched in the ice but at lower enrichment indices than the particulate phase, suggesting that size is a key factor for the incorporation of impurities in sea ice. Low chlorophyll a concentrations and the fit of the macro-nutrients (with the exception of ammonium) with their theoretical dilution lines indicated low biological activity in the ice. From these and additional results we conclude that physical processes are the dominant mechanisms leading to the enrichment of DFe, PFe, organic matter and bacteria in young sea ice, and that PFe and DFe are decoupled during sea-ice formation. Our study thus provides unique quantitative insight into the initial incorporation of impurities, in particular DFe and PFe, into Antarctic sea ice.

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“…Moving from conceptual models to numerical parameterisations requires generalized quantification of processes, something which is lacking for many sea-ice biogeochemical processes. One example is the finding that melting sea ice enriched in iron and organic matter contributes to pelagic ice-edge phytoplankton blooms in the surface ocean (Lancelot et al, 2009;Lannuzel et al, 2013;Wang et al, 2014). While mesocosm experiments confirm the process, field observations remain unclear on the specific mechanism and thus on the large-scale importance of such ice-associated iron fertilization.…”

Section: Figurementioning

confidence: 98%

What sea-ice biogeochemical modellers need from observers

et al. 2016

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Numerical models can be a powerful tool helping to understand the role biogeochemical processes play in local and global systems and how this role may be altered in a changing climate. With respect to sea-ice biogeochemical models, our knowledge is severely limited by our poor confidence in numerical model parameterisations representing those processes. Improving model parameterisations requires communication between observers and modellers to guide model development and improve the acquisition and presentation of observations. In addition to more observations, modellers need conceptual and quantitative descriptions of the processes controlling, for example: primary production and diversity of algal functional types in sea ice, ice algal growth, release from sea ice, heterotrophic remineralisation, transfer and emission of gases (e.g., DMS, CH 4 , BrO), incorporation of seawater components in growing sea ice (including Fe, organic and inorganic carbon, and major salts) and subsequent release; CO 2 dynamics (including CaCO 3 precipitation), flushing and supply of nutrients to sea-ice ecosystems; and radiative transfer through sea ice. These issues can be addressed by focused observations, as well as controlled laboratory and field experiments that target specific processes. The guidelines provided here should help modellers and observers improve the integration of measurements and modelling efforts and advance toward the common goal of understanding biogeochemical processes in sea ice and their current and future impacts on environmental systems.

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Effect of melting Antarctic sea ice on the fate of microbial communities studied in microcosms

Cited by 31 publications

References 62 publications

Impact of sea ice on the marine iron cycle and phytoplankton productivity

Impact of sea ice on the marine iron cycle and phytoplankton productivity

Incorporation of iron and organic matter into young Antarctic sea ice during its initial growth stages

What sea-ice biogeochemical modellers need from observers

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