MEPS 314:239-255 (2006)  -  doi:10.3354/meps314239

Sedimentation following the spring bloom in Disko Bay, West Greenland, with special emphasis on the role of copepods

Thomas Juul-Pedersen1,2, Torkel Gissel Nielsen1,*, Christine Michel2, Eva Friis Møller1,3, Peter Tiselius4, Peter Thor4, Michael Olesen5, Erik Selander4, Saskia Gooding1

1National Environmental Research Institute, Department of Marine Ecology, Frederiksborgvej 399, 4000 Roskilde, Denmark
2Freshwater Institute, Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, Manitoba R3T 2N6, Canada
3University of Århus, Department of Marine Ecology, Finlandsgade 14, 8200 Århus, Denmark
4Göteborg University, Department of Marine Ecology, Kristineberg Marine Research Station, 450 34 Fiskebäckskil, Sweden
5Copenhagen University, Zoological Institute, Marine Biological Laboratory, Strandpromenaden 5, 3000 Helsingør, Denmark
*Corresponding author. Email:

ABSTRACT: The sedimentation of particulate organic material was investigated in Disko Bay, West Greenland, during June 2001. Post spring-bloom conditions were encountered, with seasonally decreasing phytoplankton biomass associated with the pycnocline. Calanus finmarchicus, C. glacialis, and C. hyperboreus dominated the zooplankton community, comprising up to 88% of the copepod biomass. Faecal pellet production by C. finmarchicus and C. glacialis was positively correlated to the available food (chlorophyll a >10 µm). Results from short-term sediment trap deployments (6 h) showed that particulate organic carbon (POC) sedimentation from the euphotic zone was, on average, 628 mg C m–2 d–1, with copepod faecal pellets contributing, on average, 29% of this amount. The faecal pellet contribution to the vertical sinking export of POC was equivalent to that of phytoplankton and amorphous detritus. Yet, on average, 35% of the copepod faecal pellet production was retained within the euphotic zone. The POC:PON (particulate organic nitrogen) ratio of the suspended material in the euphotic zone (8.1 ± 0.4) was comparable to that of the material collected in the sediment traps just below the euphotic zone (8.0 ± 0.9). In addition, the daily loss rates of POC and PON within each sampling depth were similar, and the carbon to nitrogen ratio in the sediment traps did not change with depth. These results indicate that the pelagic system had a low retention efficiency of nitrogen just after the spring bloom.

KEY WORDS: Arctic marine ecology · Sedimentation · Faecal pellet production · Calanus spp. · Carbon flux

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