title: Broad-scale predictability of carbohydrates and exopolymers in Antarctic and Arctic sea ice.
abstract: 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.
authors.affiliation: School of Biological Sciences, University of Essex, Colchester, Essex CO4 3SQ, United Kingdom.
authors.forename: Graham J C
authors.initials: GJ
authors.lastname: Underwood
authors.forename: Shazia N
authors.initials: SN
authors.lastname: Aslam
authors.forename: Christine
authors.initials: C
authors.lastname: Michel
authors.forename: Andrea
authors.initials: A
authors.lastname: Niemi
authors.forename: Louiza
authors.initials: L
authors.lastname: Norman
authors.forename: Klaus M
authors.initials: KM
authors.lastname: Meiners
authors.forename: Johanna
authors.initials: J
authors.lastname: Laybourn-Parry
authors.forename: Harriet
authors.initials: H
authors.lastname: Paterson
authors.forename: David N
authors.initials: DN
authors.lastname: Thomas
mesh_terms: D000864:Antarctic Regions; D001110:Arctic Regions; D001704:Biopolymers / Q000032:analysis*; D002241:Carbohydrates / Q000032:analysis*; D046448:Ice Cover / Q000737:chemistry*; D008956:Models, Chemical; D008970:Molecular Weight; D012995:Solubility
chemical_list: D001704:Biopolymers; D002241:Carbohydrates
keywords: algae; biogeochemistry; global relationships; microbial
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