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Cleary, A. C., University of Rhode Island Graduate School of Oceanography, Narragansett, USA, acleary@gso.uri.edu
Durbin, E. G., University of Rhode Island Graduate School of Oceanography, Narragansett, USA, edurbin@gso.uri.edu
Rynearson, T. A., University of Rhode Island Graduate School of Oceanography, Narragansett, USA, rynearson@gso.uri.edu

NORTHERN KRILL BRING SEDIMENT CARBON BACK TO THE PELAGIC: DNA IN MEGANYCTIPHANES NORVEGICA GUT CONTENTS SHOWS BENTHIC FEEDING

Krill are key members of many marine ecosystems, as a trophic link between microscopic plankton and large predators such as fish, whales and seabirds. Krill in-situ diet, currently considered mainly planktivorous, is thus important to carbon cycling through the ecosystem. We took a novel DNA based approach to measure Northern krill, Meganyctiphanes norvegica, in-situ feeding in the Gulf of Maine. 18S clone libraries were constructed from a PCR with universal primers and a krill-specific Peptide Nucleic Acid blocking probe. The most common prey items were then quantified in individual krill guts with prey species-specific quantitative PCR. We identified an unknown benthic microeukaryote that comprised approximately half of krill diets in the Gulf of Maine. Krill feeding on the sediment is a new pathway for carbon flow from the sediments to the pelagic, opposite to classical carbon flows from surface waters to the sediment. We estimate that over 100,000 tons of carbon are brought back into the Gulf of Maine pelagic ecosystem annually by krill benthic feeding, more than that required by the region’s entire fin whale population.

Session #:S21
Date: 02-16-2011
Time: 08:30

Presentation is given by student: Yes