On the trophic coupling between protists and copepods in arctic marine ecosystems

• Published in: Marine ecology. Progress series (Halstenbek) 2000-10, Vol.204, p.65-77
• Main Authors: Levinsen, Henrik, Turner, Jefferson T., Nielsen, Torkel G., Hansen, Benni W.
• Format: Article
• Language: English
• Subjects: Acartia longiremis; Animal and plant ecology; Animal, plant and microbial ecology; Arctic; Biological and medical sciences; Biomass; Calanus; Calanus finmarchicus; Calanus glacialis; Calanus hyperboreus; Ciliata; Copepoda; Diatoms; Fundamental and applied biological sciences. Psychology; Grazing; Grazing experiments; Greenland; Ingestion; Marine; Marine ecosystems; Omnivores; Phaeocystis; Phytoplankton; Plankton; Protista; Sea water ecosystems; Surface water; Synecology
• ISSN: 0171-8630; 1616-1599
• DOI: 10.3354/meps204065

Grazing experiments were conducted at different seasons with the largeCalanus finmarchicus,C. glacialisandC. hyperboreus, and the smallAcartia longiremisin Disko Bay, West Greenland and Young Sound, NE Greenland. Female copepods incubated in 200 μm screened natural water preferred large protists. Thus, particularly during the post-bloom period, the relatively large heterotrophic protists (ciliates and heterotrophic dinoflagellates) contributed substantially to the trophic coupling between protists and copepods. However, low grazing byC. glacialisandC. hyperboreusin mid-June suggests that large parts of the populations of these species had terminated feeding at this time, prior to overwintering. Clearance increased with ciliate and dinoflagellate size above 10 μm equivalent spherical diameter (ESD), equal to the size of the smallest heterotrophic protists. At a size of 30 to 40 μm ESD maximum clearance was observed. Grazing onPhaeocystissingle cells of 5 μm byC. finmarchicusshowed a lower size-limit for capture of this species