Microbial community succession in a DOM degradation experiment

In the marine environment, labile carbon is mostly represented by the dissolved organic matter (DOM) pool freshly produced by phytoplankton and mixoplankton through photosynthesis. Heterotrophic bacteria communities quickly use labile DOM leaving behind residual fractions such that the DOM pool becomes increasingly recalcitrant. This recalcitrant DOM (rDOM) may persist in the ocean for extended time scales. Within this experiment, the hypothesis was tested that heterotrophic bacterial activity successively degrade DOM in marine waters supports and this enables the gradual appearance of nitrification. Natural communities of microbes collected from the Western English Channel Observatory station E1 were exposed to coccolithophore-derived DOM and varying ammonium concentrations, and the change to DOM concentration, nutrients and microbial community structure was tracked for 362 days. Vessels of 10 L (triplicates) were incubated in the dark at 10 C.Water samples (200 mL) for 16S rRNA gene metabarcode sequencing were filtered onto 0.22 micron PES filters (Merck-Millipore, Gillingham, UK) using sterile equipment. Genomic DNA was extracted using the DNeasy PowerWater kit according to the manufacturers instructions (Qiagen, Manchester, UK). High-throughput DNA sequencing was performed by NU-OMICS (Northumbria University, UK) using the 16S rRNA gene primer pairs 515F-Y (GTGYCAGCMGCCGCGGTAA) and 806R (GGACTACHVGGGTWTCTAAT). Sequencing was performed on a MiSeq Personal Sequencer (Illumina, San Diego, CA, USA) using the V2 500 reagent kit. These data may be copied, published, distributed, transmitted and adapted to be exploited commercially and non-commercially, with acknowledgment of Plymouth Marine Laboratory (PML) as the data originator, in line with version 3 of the UK Open Government Licence (OGL) (https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/).