MEPS 434:77-90 (2011)  -  doi:10.3354/meps09188

Metazooplankton community structure, feeding rate estimates, and hydrography in a meltwater-influenced Greenlandic fjord

Kam W. Tang1,*, Torkel Gissel Nielsen2, Peter Munk2, John Mortensen3, Eva Friis Møller4, Kristine Engel Arendt3, Kajsa Tönnesson5, Thomas Juul-Pedersen3

1Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, Virginia 23062, USA
2National Institute of Aquatic Resources, DTU Aqua, Section for Ocean Ecology and Climate, Technical University of Denmark, Kavalergården 6, 2920 Charlottenlund, Denmark
3Greenland Climate Research Centre, c/o Greenland Institute of Natural Resources, PO Box 570, Kivioq 2, 3900 Nuuk, Greenland
4Department of Marine Ecology, National Environmental Research Institute, Aarhus University, 4000 Roskilde, Denmark
5Department of Marine Ecology, University of Gothenburg, Box 461, 405 30 Göteborg, Sweden

ABSTRACT: In order to assess the potential responses of Greenland’s coastal ecosystems to future climate change, we studied the hydrography and distribution of metazooplankton, along a transect from the slope waters beyond Fyllas Banke to the inner part of Godthåbsfjord, West Greenland, in July and August 2008, and estimated feeding rates for some of the larger species groups. Within the 4 regional domains that were covered in the study (continental slope, continental shelf, outer sill region, and main fjord basin), salty coastal water and glacial runoff mixed to various extents, and 7 water masses with specific characteristics were identified. The common large copepod species were Calanus finmarchicus, C. glacialis, C. hyperboreus, and Metridia longa. Small copepod genera included Microsetella, Pseudocalanus, and Oithona, while rotifers and gastropods (primarily pteropods) were also found in high abundance. Species could be linked to the specific water masses, e.g. Calanus spp. were primarily associated with oceanic or coastal waters, whereas M. longa, Microsetella sp., Pseudocalanus sp., and rotifers were mostly found inside the fjord. The combined biomass of the large zooplankton species (5.5 × 103 mg C m–2) was less than that of the small species (6.8 × 103 mg C m–2) averaged across all sampled stations along the transect. Estimated in situ grazing rates for the large copepod species were <10% of their maximum rates, indicating food limitation. The major predatory zooplankton groups, Pareuchaeta norvegica and chaetognaths, had estimated predation effects of <1% d–1 on the prey community. The dominance of small zooplankton species within the fjord contradicts the traditional emphasis on large, lipid-rich zooplankton species in the arctic seas, and suggests that the planktonic food web structure inside the glacial fjord was different from that of the system outside.

KEY WORDS: Glacial fjord · Greenland · Climate change · Copepod · Grazing · Predation · Food web

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Cite this article as: Tang KW, Nielsen TG, Munk P, Mortensen J and others (2011) Metazooplankton community structure, feeding rate estimates, and hydrography in a meltwater-influenced Greenlandic fjord. Mar Ecol Prog Ser 434:77-90

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