Experimental assessment of the effect of grazing, resources and light on marine prokaryotes in surface oligotrophic waters. Effect of grazing, resources and light on marine prokaryotes

To evaluate the importance of grazing and resource availability as well as of solar radiation on prokaryotic taxonomic community composition in surface waters of the tropical and subtropical oceans, a series of 10 microcosm experiments were conducted from December 2010 to June 2011 at 10 stations located between 30 ºN and 30ºS in the Atlantic (4 experiments), Pacific (4 experiments) and Indian (2 experiments) oceans from December 2010 to June 2011. Grazing pressure was manipulated through sample filtration, resource availability through dilution of filtered samples, and solar radiation by exposing filtered and diluted samples either to natural full sunlight or total darkness. Growth rates at the community level were estimated from biomass and production data and while community composition was explored using high-throughput 16S rRNA amplicon sequencing.