Aquatic Microbial Ecology

Inter-Research
Aquatic Microbial Ecology

IR Home



AME
Home
Editors
Forthcoming
Information
Subscribe


Journals
Home
MEPS
AME
CR
DAO
ESEP
ESR
Search
Subscribe

Book Series
EE Books
Top Books
ESEP Books
Order

EEIU Brochures
(pdf format)

Discussion Forums
Home

Research
IR Research

Institutions
International Ecology Institute
Eco-Ethics International Union

Foundation
Otto Kinne Foundation

AME 38:157-167 (2005)

Abstract

The ciliate-copepod link in marine ecosystems

Albert Calbet*, Enric Saiz

Institut de Ciències del Mar-CMIMA (CSIC), P. Marítim de la Barceloneta 37–49, Barcelona, Catalonia, Spain

*Email: acalbet@icm.csic.es

ABSTRACT: We show the results of a comparative, cross-ecosystem, analysis of the relative importance of ciliates as carbon sources for copepod, and, specifically, evaluated the strength of the ciliate-copepod trophic link. Although phytoplankton represent, globally, a far higher biomass than ciliates (>1 order of magnitude), the consumption of the latter nevertheless comprises, on average, 30% of copepod daily carbon rations (ciliates + phytoplankton). The relative importance of ciliate consumption by copepods clearly depends on the trophic state of the system. In regions where phytoplankton concentrations are low (<50 µgC l–1), ciliate and phytoplankton contribution to the diet are equivalent. In richer environments this value declines, with ciliates accounting for only 25 and 22% of diet in environments characterized by phytoplankton concentrations of 50–500 and >500 µgC l–1, respectively. From a biogeochemical point of view, our carbon budget estimates indicate that copepods process, on a global scale, 5.5 to 8.1 gigaton (Gt) phytoplankton-derived C yr–1; from the heterotrophic side, this flux would represent 2.0 to 2.4 Gt ciliate-derived C yr–1 and, probably, a higher value would be obtained if other microheterotrophs, like heterotrophic dinoflagellates, were included. Hence, the flux of carbon from ciliates, and other microzooplankton, towards upper trophic levels should definitely be considered in oceanic biogeochemical cycles and pelagic food web models.

KEY WORDS: Ciliates · Microzooplankton · Copepods · Mesozooplankton · Feeding · Biogeochemical cycles · Remineralization · Food webs · Marine

Full text in pdf format

Published in AME Vol. 38, No. 2 (2005) on February 9
Print ISSN: 0948-3055; Online ISSN: 1616-1564. Copyright © Inter-Research, Oldendorf/Luhe, 2005

Copyright © 2005; Inter-Research
Webmaster: webmaster@int-res.com