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Titel |
Analyzing the trophic link between the mesopelagic microbial loop and zooplankton from observed depth profiles of bacteria and protozoa |
VerfasserIn |
T. Tanaka, F. Rassoulzadegan, T. F. Thingstad |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1726-4170
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Digitales Dokument |
URL |
Erschienen |
In: Biogeosciences ; 2, no. 1 ; Nr. 2, no. 1 (2005-02-01), S.9-13 |
Datensatznummer |
250000375
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Publikation (Nr.) |
copernicus.org/bg-2-9-2005.pdf |
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Zusammenfassung |
It is widely recognized that organic carbon exported to the ocean aphotic
layer is significantly consumed by heterotrophic organisms such as bacteria
and zooplankton in the mesopelagic layer. However, very little is known for
the trophic link between bacteria and zooplankton or the function of the
microbial loop in this layer. In the northwestern Mediterranean, recent
studies have shown that viruses, bacteria, heterotrophic nanoflagellates,
and ciliates distribute down to 2000 m with group-specific depth-dependent
decreases, and that bacterial production decreases with depth down to 1000 m.
Here we show that such data can be analyzed using a simple steady-state
food chain model to quantify the carbon flow from bacteria to zooplankton
over the mesopelagic layer. The model indicates that bacterial mortality by
viruses is similar to or 1.5 times greater than that by heterotrophic nanoflagellates, and that
heterotrophic nanoflagellates transfer little of bacterial production to
higher trophic levels. |
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