MEPS 217:235-250 (2001)  -  doi:10.3354/meps217235

Abundance, biomass, composition and grazing impact of the sea-ice meiofauna in the North Water, northern Baffin Bay

Christian Nozais1,*, Michel Gosselin1, Christine Michel2, Guglielmo Tita1,**

1Institut des sciences de la mer de Rimouski (ISMER), Université du Québec à Rimouski, 310 Allée des Ursulines, Rimouski, Québec G5L 3A1, Canada
2Fisheries and Oceans, Freshwater Institute, 501 University Crescent, Winnipeg, Manitoba R3T 2N6, Canada
*E-mail: **Present address: Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70808, USA

ABSTRACT: The abundance, biomass, composition and grazing impact of the bottom sea-ice meiofauna were investigated in the North Water, High Arctic, during April and May 1998. Sampling was conducted on both pack ice and land fast-ice. At the lowermost 2 to 4 cm of the sea ice, chlorophyll a reached a maximum concentration of 55.7 mg m-2. Sea-ice meiofauna were observed only at the ice bottom, and were composed of nematodes, copepods (harpacticoids and cyclopoids), crustacean nauplii, polychaete larvae and turbellarians. Total abundance of sea-ice meiofauna ranged from 0 to 34500 ind. m-2 at the sampling stations. Nematodes were the most abundant taxon in the ice, with highest densities at a land fast-ice station. Highest abundances of copepods as well as crustacean nauplii were observed in the pack ice. The total sea-ice meiofauna biomass varied between 0 and 19.4 mg C m-2. Potential ingestion rates, determined using allometric equations, indicated that sea-ice meiofauna never consumed more than 0.9% of the ice-algae standing stock and 5.7% of the daily ice-algae production. These calculations strongly suggest that the grazing impact of sea-ice meiofauna on ice algae was negligible in the North Water in early spring. The low standing stock of ice meiofauna also precludes their potential as an important food source for higher trophic levels. Meiofauna, therefore, appear to be a minor contributor to the overall carbon flow in the sea-ice biota of the North Water during spring.

KEY WORDS: Arctic polynya · Sea ice · Algae · Meiofauna · Grazing impact

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