MEPS 248:1-13 (2003)  -  doi:10.3354/meps248001

Vertical distribution of exopolymer particles in sea ice of the Fram Strait (Arctic) during autumn

Klaus Meiners1,5,*, Rolf Gradinger2, Johanna Fehling1,3, Giuseppe Civitarese4, Michael Spindler1

1Institute for Polar Ecology, University of Kiel, Wischhofstraße 1-3, Gebäude 12, 24148 Kiel, Germany
2Institute of Marine Science, University of Alaska, Fairbanks, Alaska 99775, USA
3Dunstaffnage Marine Laboratory, Scottish Association for Marine Science, Oban PA34 4AB, Scotland, UK
4Consiglio Nazionale delle Ricerche (CNR), Istituto di Scienze Marine, 34123 Trieste, Italy
5Present address: Yale University, Dept. of Geology and Geophysics, PO Box 208109, New Haven, Connecticut 06520-8109, USA

ABSTRACT: The concentration and size distribution of exopolymer particles were measured in and below pack ice in the Fram Strait area during autumn 1999. Vertical profiles of exopolymer particles were determined in young, first-year and multi-year sea ice. In addition, a variety of abiotic parameters (temperature, salinity, NO2, PO4, NO3, SiO2) and biotic parameters (particulate organic carbon [POC] and nitrogen [PON], chlorophyll a [chl a], abundances of diatoms and bacteria) were measured. Median abundances and areas of exopolymer particles in the different ice types (3.17 x 106 to 4.90 x 106 particles l-1 and 4.6-6.9 cm2 l-1, respectively) exceeded median concentrations in the under-ice water (0.56 x 106 particles l-1; 0.6 cm2 l-1) by 1 order of magnitude. Exopolymer particle concentrations in sea ice were highest in the interior of the sea ice and were significantly correlated with chl a as well as with the abundances of pennate diatoms, centric diatoms and bacteria. Our data indicate that pennate diatoms are the main producers of exopolymer particles in sea ice. The observed exopolymer particle-size spectra in both sea ice and under-ice water differed from those commonly reported for exopolymer particles in pelagic environments by a relatively large fraction of large particles. Crude estimates of integrated exopolymer particle carbon indicate that these particles can be important components in the context of food-web structure and organic carbon dynamics in the sea ice habitat. The high concentrations of exopolymer particles in the sea ice will also impact the fate of other particles during ice melt.

KEY WORDS: Sea ice · Nutrients · Exopolymer particles · Extracellular polymeric substances · EPS · Diatoms · Bacteria

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