Heterotrophic Protists Associated with Sea Ice

Caron, David A.; Gast, Rebecca J.

doi:10.1002/9781444317145.ch9

Cited by 15 publications

(16 citation statements)

References 117 publications

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“…Ice algae have been estimated conservatively to contribute between 4% and 20% of total annual primary production in the ice-covered regions of the polar oceans (42) and are an important source of carbon within the ice system (42). Diatoms are a major algal group in sea ice, dominating bottom assemblages in both Arctic and Antarctic ecosystems (42,43), and were the dominant algal group in the majority of the datasets used here (see references in Table S1). Bacteria also contribute to the EPS pool in ice (15,20), although bacterial biomass and production is not necessarily closely coupled to algal autotrophic activity in sea ice (36).…”

Section: Discussionmentioning

confidence: 99%

Broad-scale predictability of carbohydrates and exopolymers in Antarctic and Arctic sea ice

Underwood

Aslam

Michel

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Sea ice can contain high concentrations of dissolved organic carbon (DOC), much of which is carbohydrate-rich extracellular polymeric substances (EPS) produced by microalgae and bacteria inhabiting the ice. Here we report the concentrations of dissolved carbohydrates (dCHO) and dissolved EPS (dEPS) in relation to algal standing stock [estimated by chlorophyll (Chl) a concentrations] in sea ice from six locations in the Southern and Arctic Oceans. Concentrations varied substantially within and between sampling sites, reflecting local ice conditions and biological content. However, combining all data revealed robust statistical relationships between dCHO concentrations and the concentrations of different dEPS fractions, Chl a, and DOC. These relationships were true for whole ice cores, bottom ice (biomass rich) sections, and colder surface ice. The distribution of dEPS was strongly correlated to algal biomass, with the highest concentrations of both dEPS and non-EPS carbohydrates in the bottom horizons of the ice. Complex EPS was more prevalent in colder surface sea ice horizons. Predictive models (validated against independent data) were derived to enable the estimation of dCHO concentrations from data on ice thickness, salinity, and vertical position in core. When Chl a data were included a higher level of prediction was obtained. The consistent patterns reflected in these relationships provide a strong basis for including estimates of regional and seasonal carbohydrate and dEPS carbon budgets in coupled physical-biogeochemical models, across different types of sea ice from both polar regions. S ea ice covers extensive regions of the Arctic and SouthernOceans, as well as some subpolar seas, and exhibits major annual, interannual, and long-term climate-related variability in age, thickness, and structure (1-3). Sea ice is not an inert physical barrier to air-ocean exchange (4), and both microbial activity and physico-chemical reactions within the ice contribute to regional-scale biogeochemical processes at the air-ocean surface interface (5).Sea ice provides a range of habitats for diverse biological assemblages that are characterized by high standing stocks of microalgae and bacteria (6). These microorganisms produce large quantities of dissolved organic carbon (DOC), often in the form of carbohydrate-rich extracellular polymeric substances (EPS) (7). Microbial EPS exist in a dynamic equilibrium from dissolved polysaccharides (dEPS <0.2 μm) to complex particulate EPS that can form gels on the millimeter to centimeter scale (8). Here we focus on the biologically relevant dissolved carbohydrates (dCHO) that constitute a substantial fraction of the DOC in sea ice (9-13) (Fig. 1). dCHO are concentrated from sea ice DOC by dialysis (>8 kDa), with subsequent treatment allowing the definition of four subcomponents of the total dCHO pool: (i) dissolved uronic acids (dUA), produced by ice diatoms and ice bacteria (14-16), that confer strong cross-linkages between polymer chains (8), forming low solubility EPS complexes w...

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Section: Discussionmentioning

confidence: 99%

Broad-scale predictability of carbohydrates and exopolymers in Antarctic and Arctic sea ice

Underwood

Aslam

Michel

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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“…Principal among these efforts was the determination of heat flux from the polar ocean to the atmosphere, especially during winter (Untersteiner, 1964). The exploration of sea ice algal communities in brine began in the 1960s; these communities held interest for polar biologists as both extremophiles and as potentially important elements in the polar ocean food web (Arrigo et al, 2010;Caron and Gast, 2010). By 1965, it had been established that at least two microalgal communities existed in sea ice:…”

Section: Sea Ice Biogeochemistry and Materials Transport Across The Frmentioning

confidence: 99%

Sea Ice Biogeochemistry and Material Transport Across the Frozen Interface

Loose¹,

Miller²,

Elliott³

et al. 2011

Oceanog.

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“…In the past decade, there have been several excellent reviews on the microbiology of both the water column (Staley and Gosink, 1999;Hollibaugh et al, 2007;Lovejoy et al, 2010;Lovejoy, 2011Lovejoy, , 2014Boeuf et al, 2014) and sea ice (Deming, 2010;Caron and Gast, 2010;Arrigo et al, 2014) in the Arctic. The contribution of arctic microbes to element cycles has also been reviewed by Wassmann (2006Wassmann ( , 2011, and there have been a number of publications on the ecology and character of marine microbes in the Arctic (Galand et al, 2006(Galand et al, , 2008aSala et al, 2008;Alonso-Sáez et al, 2008, 2010Estrada et al, 2009;Cottrell and Kirchman, 2009;Kirchman et al, 2009;Terrado et al, 2011).…”

Section: Introductionmentioning

confidence: 99%