We are grateful to Atlas South Sea Pearl Ltd for providing us with pearl oysters and a seeding technician for this experiment. “
“Phytoplankton accounts for less than 1% of the photosynthetic biomass on Earth, yet is estimated to contribute half of the world’s net primary production (Field et al., 1998). A substantial fraction of the global carbon flux is controlled by the prokaryotic fraction of the plankton (Binaschi et al., 2001), the so-called bacterioplankton, selleck kinase inhibitor which consist of different heterotrophic taxa with varying ecological strategies (Giovannoni, 2005). Studies based on culture-independent 16S ribosomal RNA gene sequence (16S rDNA)

analysis and transcriptome-based approaches provided insights into the dynamics and functional interactions within such communities (Gilbert et al., 2008). However, several questions remain unanswered, e.g. how a multitude of eukaryotic and prokaryotic planktonic species coexist in a seemingly homogenous habitat with limited resources (Glöckner, 2011). In previous studies,

we used a comprehensive multi-‘omic’ approach to investigate the bacterioplankton’s response to a diatom-dominated spring phytoplankton bloom off the coast of the island Helgoland in the year 2009 (Klindworth HSP inhibitor cancer et al., 2014 and Teeling et al., 2012). We observed a tight succession of distinct blooming bacterial clades. Flavobacteria (genera Ulvibacter, Formosa, and Polaribacter) and Gammaproteobacteria (genus Reinekea and SAR92 clade species) acted as major polymer degrader while Alphaproteobacteria (SAR11 clade and Rhodobacteraceae) appeared to hardly benefit from abound algae substrates. The combined analysis of metagenomes, metatranscriptomic and metaproteomes from different time points throughout the succession uncovered differences in the gene repertoires and expression ADP ribosylation factor profiles of distinct clades. The metatranscriptome reported in this study was generated as part of the same sampling campaign but addressing the winter

time before the spring phytoplankton bloom. Prior to appearance of the algae bloom surface water was collected on 11.02.2009 from the long-term ecological research site ‘Kabeltonne’ off the coast of the island Helgoland in the German Bight of the North Sea (54°11.18′N, 7°54.00′E) as described previously (Teeling et al., 2012). RNA extraction was performed without mRNA enrichment and the cleaned total RNA sample was subsequently used for cDNA synthesis as reported by Klindworth et al. (Klindworth et al., 2014). Roche’s 454 pyrosequencing was carried out at LGC Genomics (LGC Genomics GmbH, Berlin, Germany) using the FLX Titanium chemistry (Roche/454 Life Sciences, Branford, CT, USA) according to the manufacturers protocols. The sequencing statistics are summarized in Table 1. Extraction of expressed 16S rDNA fragments from metatranscriptome and their subsequent taxonomic assignments were done with the SILVA pipeline (Quast et al., 2013), which uses the SINA aligner (Pruesse et al., 2012).