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Growth and herbivory by heterotrophic dinoflagellates in the Southern Ocean, studied by microcosm experiments

Growth and herbivory by heterotrophic dinoflagellates in the Southern Ocean, studied by microcosm... 227 109 109 3 3 P. K. Bjørnsen J. Kuparinen Marine Biological Laboratory Strandpromenaden 5 DK-3000 Helsingør Denmark Finnish Institute of Marine Research P.O. Box 33 SF-00931 Helsinki Finland Abstract Growth and herbivory of heterotrophic dinoflagellates ( Gymnodinium sp.) from the Weddell Sea and the Weddell/Scotia Confluence were studied in 1988 in 100-liter microcosms. The microcosms were screened through 200- µ m or 20- µ m mesh nets and incubated for 12 d at 1 °C under artificial light. Mean cell volume of dinoflagellates was 1 000 to 1 500 µ m 3 , and that of their phytoplankton prey 360 to 430 µ m 3 . Dinoflagellate growth rate followed a Holling type II functional response, with a maximum growth rate of 0.3 d −1 and half-saturation food concentrations of 1.0 µ g chlorophyll a l −1 , 50 µ g C l −1 , or 1 500 cells ml −1 . Carbon budgets based on 14 CO 2 assimilation and biomasses of phytoplankton and heterotrophic dinoflagellates suggested a balance between phytoplankton grazing loss and dinoflagellate consumption, assuming a dinoflagellate carbon conversion efficiency of 40%. Applying this to the functional response yielded estimates of maximum ingestion rate (0.8 µ g C µ g −1 C d −1 , or 6 pg C dinoflagellate −1 h −1 ) and maximum clearance (0.8 to 1.2 × 10 5 body volumes h −1 , or 80 to 120 nl ind. −1 h −1 ). The microcosm experiments suggested that heterotrophic dinoflagellates may contribute significantly to maintenance of low phytoplankton biomass in the Southern Ocean. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Marine Biology Springer Journals

Growth and herbivory by heterotrophic dinoflagellates in the Southern Ocean, studied by microcosm experiments

Marine Biology , Volume 109 (3) – Oct 1, 1991

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References (37)

Publisher
Springer Journals
Copyright
Copyright © 1991 by Springer-Verlag
Subject
Life Sciences; Biomedicine general; Oceanography; Ecology; Microbiology; Zoology
ISSN
0025-3162
eISSN
1432-1793
DOI
10.1007/BF01313505
Publisher site
See Article on Publisher Site

Abstract

227 109 109 3 3 P. K. Bjørnsen J. Kuparinen Marine Biological Laboratory Strandpromenaden 5 DK-3000 Helsingør Denmark Finnish Institute of Marine Research P.O. Box 33 SF-00931 Helsinki Finland Abstract Growth and herbivory of heterotrophic dinoflagellates ( Gymnodinium sp.) from the Weddell Sea and the Weddell/Scotia Confluence were studied in 1988 in 100-liter microcosms. The microcosms were screened through 200- µ m or 20- µ m mesh nets and incubated for 12 d at 1 °C under artificial light. Mean cell volume of dinoflagellates was 1 000 to 1 500 µ m 3 , and that of their phytoplankton prey 360 to 430 µ m 3 . Dinoflagellate growth rate followed a Holling type II functional response, with a maximum growth rate of 0.3 d −1 and half-saturation food concentrations of 1.0 µ g chlorophyll a l −1 , 50 µ g C l −1 , or 1 500 cells ml −1 . Carbon budgets based on 14 CO 2 assimilation and biomasses of phytoplankton and heterotrophic dinoflagellates suggested a balance between phytoplankton grazing loss and dinoflagellate consumption, assuming a dinoflagellate carbon conversion efficiency of 40%. Applying this to the functional response yielded estimates of maximum ingestion rate (0.8 µ g C µ g −1 C d −1 , or 6 pg C dinoflagellate −1 h −1 ) and maximum clearance (0.8 to 1.2 × 10 5 body volumes h −1 , or 80 to 120 nl ind. −1 h −1 ). The microcosm experiments suggested that heterotrophic dinoflagellates may contribute significantly to maintenance of low phytoplankton biomass in the Southern Ocean.

Journal

Marine BiologySpringer Journals

Published: Oct 1, 1991

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