Prochlorophytes as secondary prey for heterotrophic nanoflagellates in the deep chlorophyll maximum layer of the (sub)tropical North Atlantic

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MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 204:53-63 (2000) - doi:10.3354/meps204053 Prochlorophytes as secondary prey for heterotrophic nanoflagellates in the deep chlorophyll maximum layer of the (sub)tropical North Atlantic Bouwe R. Kuipers*, Harry J. Witte Department of Biological Oceanography, Netherlands Institute of Sea Research, PO Box 59, 1790 AB Den Burg, The Netherlands *E-mail: bouwe@nioz.nl ABSTRACT: Growth rates in prochlorophytes and their loss rates to grazing were investigated by the dilution technique in the lower euphotic zone of the (sub)tropical North Atlantic. Directly above the Œdeep chlorophyll maximum¹ (DCM), prochlorophyte growth rates were approximately 0.3 d-1 and grazing rates 0.4 d-1; both rates were considerably lower in and directly below the DCM. Grazing was only weakly affected by filtration through 3 µm pore-size filters, indicating heterotrophic nanoflagellates as the main grazers. Discrimination between day and night revealed that the prochlorophytes above the DCM, with doubling times of 3 d or more, divided during the day whereas at greater depth division occurred during the night. In contrast, grazing was always restricted to the daylight period and grazing rate was independent of prochlorophyte abundance, growth rate or time of division. Prochlorophyte grazing rates were, however, correlated with the loss rates in the much more abundant heterotrophic bacteria in the same layers. We conclude therefore that prochlorophytes are consumed as a secondary prey by heterotrophic nanoflagellates grazing on heterotrophic bacteria. KEY WORDS: Prochlorophytes · Heterotrophic bacteria · Grazing · Heterotrophic nanoflagellates · Deep chlorophyll maximum · North Atlantic Ocean Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 204. Online publication date: October 05, 2000 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2000 Inter-Research.