The functional biology and trophic role of krill (Thysanoessa raschii) in a Greenlandic fjord

TY - JOUR

T1 - The functional biology and trophic role of krill (Thysanoessa raschii) in a Greenlandic fjord

AU - Agersted, Mette Dalgaard

AU - Nielsen, Torkel Gissel

AU - Munk, Peter

AU - Vismann, B.

AU - Arendt, K.E.

PY - 2011/6

Y1 - 2011/6

N2 - Despite being a key zooplankton group, knowledge on krill biology from the Arctic is inadequate. The present study examine the functional biology and evaluate the trophic role of krill in the Godthåbsfjord (64°N, 51°W) SW Greenland, through a combination of fieldwork and laboratory experiments. Krill biomass was highest in the middle fjord and inner fjord, whereas no krill was found offshore. The dominating species Thysanoessa raschii revealed a type III functional response when fed with the diatom Thalassiosira weissflogii. At food saturation, T. raschii exhibited a daily ration of 1% body C d -1 . Furthermore, T. raschii was capable of exploiting plankton cells from 5 to 400 μm, covering several trophic levels of the pelagic food web. The calculated grazing impact by T. raschii on the fjord plankton community was negligible. However, the schooling and migratory behaviour of krill will concentrate and elevate the grazing in specific areas of the euphotic zone.

AB - Despite being a key zooplankton group, knowledge on krill biology from the Arctic is inadequate. The present study examine the functional biology and evaluate the trophic role of krill in the Godthåbsfjord (64°N, 51°W) SW Greenland, through a combination of fieldwork and laboratory experiments. Krill biomass was highest in the middle fjord and inner fjord, whereas no krill was found offshore. The dominating species Thysanoessa raschii revealed a type III functional response when fed with the diatom Thalassiosira weissflogii. At food saturation, T. raschii exhibited a daily ration of 1% body C d -1 . Furthermore, T. raschii was capable of exploiting plankton cells from 5 to 400 μm, covering several trophic levels of the pelagic food web. The calculated grazing impact by T. raschii on the fjord plankton community was negligible. However, the schooling and migratory behaviour of krill will concentrate and elevate the grazing in specific areas of the euphotic zone.

KW - EUPHAUSIA-SUPERBA DANA

KW - MARGINAL ICE-ZONE

KW - COPEPOD ACARTIA-TONSA

KW - ANTARCTIC KRILL

KW - FEEDING-BEHAVIOR

KW - BODY-SIZE

KW - MEGANYCTIPHANES-NORVEGICA

KW - VERTICAL-DISTRIBUTION

KW - COASTAL WATERS

KW - FECAL MATERIAL

U2 - 10.1007/s00227-011-1657-z

DO - 10.1007/s00227-011-1657-z

M3 - Journal article

SN - 0025-3162

VL - 158

SP - 1387

EP - 1402

JO - Marine Biology

JF - Marine Biology

IS - 6

ER -