TY - DATA ID - fernndezmndez2014bcop T1 - Biogeochemical characterization of pennate diatom and Melosira arctica ice algal aggregates in the Central Arctic Ocean collected in summer 2011 and 2012 AU - Fernández-Méndez, Mar AU - Wenzhöfer, Frank AU - Peeken, Ilka AU - Sørensen, Heidi L AU - Glud, Ronnie N AU - Hendricks, Stefan AU - Nicolaus, Marcel AU - Katlein, Christian AU - Nöthig, Eva-Maria AU - Bakker, Karel AU - Boetius, Antje PY - 2014/05/07/ T2 - Supplement to: Fernández-Méndez, Mar; Wenzhöfer, Frank; Peeken, Ilka; Sørensen, Heidi L; Glud, Ronnie N; Boetius, Antje; Vopel, Kay (2014): Composition, Buoyancy Regulation and Fate of Ice Algal Aggregates in the Central Arctic Ocean. PLoS ONE, 9(9), e107452, https://doi.org/10.1371/journal.pone.0107452 PB - PANGAEA DO - 10.1594/PANGAEA.832345 UR - https://doi.org/10.1594/PANGAEA.832345 N2 - Sea-ice diatoms are known to accumulate in large aggregates in and under the sea ice including melt ponds. In the Arctic, they can contribute substantially to particle export when sinking from the ice. The role and regulation of microbial aggregation in the highly seasonal, nutrient- and light-limited Arctic sea-ice ecosystem is not yet well understood, and may vary in relation to the fate of the Arctic sea-ice cover. To elucidate the mechanism controlling the formation and export of algal aggregates from sea ice, we investigated samples taken in late summer 2011 and 2012, during two cruises to the Eurasian Basin of the Central Arctic Ocean. Dense, spherical aggregates composed mainly of pennate diatoms, and filamentous aggregates formed by Melosira arctica were found in different degradation stages, with carbon to Chlorophyll a ratios ranging from 110 to 66700, and carbon to nitrogen molar ratios of 8-35 and 9-40, respectively. Fresh sub-ice algal aggregate densities ranged between 1 and 17 aggregates/m**2, corresponding to a net primary production of 0.4-40 mg C/m**2/d, contributing 3-80% of total biomass and up to 94% of total production at a local scale. A key factor controlling buoyancy of the aggregates was light intensity, regulating photosynthetic oxygen production and flotation by gas bubbles trapped within the mucous matrix, even at low ambient nutrient concentrations. Our data was used to evaluate the factors regulating the distribution and importance of the Arctic algal aggregates as carbon source for pelagic and benthic communities. ER -