Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-60006
Piwosz, K; Pernthaler, J (2011). Enrichment of omnivorous cercozoan nanoflagellates from coastal Baltic Sea waters. PLoS ONE, 6(9):e24415.
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Free-living nano-sized flagellates are important bacterivores in aquatic habitats. However, some slightly larger forms can also be omnivorous, i.e., forage upon both bacterial and eukaryotic resources. This hitherto largely ignored feeding mode may have pronounced implications for the interpretation of experiments about protistan bacterivory. We followed the response of an uncultured group of omnivorous cercozoan nanoflagellates from the Novel Clade 2 (Cerc_BAL02) to experimental food web manipulation in samples from the Gulf of Gdansk (Southern Baltic Sea). Seawater was either prefiltered through 5 mu m filters to exclude larger predators of nanoflagellates (F-treatment), or prefiltered and subsequently 1:10 diluted with sterile seawater (F+D-treatment) to stimulate the growth of both, flagellates and bacteria. Initially, Cerc_BAL02 were rapidly enriched under both conditions. They foraged on both, eukaryotic prey and bacteria, and were highly competitive at low concentrations of food. However, these omnivores were later only successful in the F+D treatment, where they eventually represented almost one fifth of all aplastidic nanoflagellates. By contrast, their numbers stagnated in the F-treatment, possibly due to top-down control by a concomitant bloom of other, unidentified flagellates. In analogy with observations about the enrichment of opportunistically growing bacteria in comparable experimental setups we suggest that the low numbers of omnivorous Cerc_Bal02 flagellates in waters of the Gulf of Gdansk might also be related to their vulnerability to grazing pressure.
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|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||07 Faculty of Science > Institute of Plant Biology|
|DDC:||580 Plants (Botany)|
|Deposited On:||03 Mar 2012 21:19|
|Last Modified:||12 Nov 2014 12:24|
|Publisher:||Public Library of Science (PLoS)|
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