- Czech Academy of Sciences Czech Republic
- Spanish National Research Council Spain
- Linnaeus University Sweden
- National Scientific and Technical Research Council Argentina
- Wageningen University & Research Netherlands
To test whether protist grazing selectively affects the composition of aquatic bacterial communities, we combined high-throughput sequencing to determine bacterial community composition with analyses of grazing rates, protist and bacterial abundances and bacterial cell sizes and physiological states in a mesocosm experiment in which nutrients were added to stimulate a phytoplankton bloom. A large variability was observed in the abundances of bacteria (from 0.7 to 2.4 × 106 cells per ml), heterotrophic nanoflagellates (from 0.063 to 2.7 × 104 cells per ml) and ciliates (from 100 to 3000 cells per l) during the experiment (~3-, 45- and 30-fold, respectively), as well as in bulk grazing rates (from 1 to 13 × 106 bacteria per ml per day) and bacterial production (from 3 to 379 μg per C l per day) (1 and 2 orders of magnitude, respectively). However, these strong changes in predation pressure did not induce comparable responses in bacterial community composition, indicating that bacterial community structure was resilient to changes in protist predation pressure. Overall, our results indicate that peaks in protist predation (at least those associated with phytoplankton blooms) do not necessarily trigger substantial changes in the composition of coastal marine bacterioplankton communities
The mesocosm experiment was supported by EU project BASICS (EVK3-CT-2002-00078). This research was supported by projects from the European Science Foundation (EuroEEFG project MOCA) and the Swedish Research Council to JP. KŠ and KH were supported by a CSIC—CAS (Spanish-Czech) bilateral mobility project awarded to JMG and KŠ. JMG is supported by project DOREMI (CTM2012-34294) and the GRC 2014SGR/1179 from Generalitat de Catalunya, and FB by a University of Otago Research Grant
14 pages, 4 figures, 1 table, supplementary Information http://www.nature.com/ismej/journal/v10/n3/suppinfo/ismej2015135s1.html
Peer Reviewed