Cunliffe M, Salter M, Mann PJ, Whiteley AS, Upstill-Goddard RC, Murrell JC
surface microlayer, Transparent exopolymer particles, TEP, Bacteria, Phytoplankton bloom, Dissolved Organic Carbon, DOC, mesocosm, 2.5 m3, Espegrend, Norway
The sea surface microlayer is the interfacial boundary layer between the marineenvironment and the troposphere. Surface microlayer samples were collectedduring a fjord mesocosm experiment to study microbial assemblage dynamicswithin the surface microlayer during a phytoplankton bloom. Transparentexopolymer particles were significantly enriched in the microlayer samples,supporting the concept of a gelatinous surface film. Dissolved organic carbon andbacterial cell numbers (determined by flow cytometry) were weakly enriched in themicrolayer samples. However, the numbers of Bacteria 16S rRNA genes (determinedby quantitative real-time PCR) were more variable, probably due to variablenumbers of bacterial cells attached to particles. The enrichment of transparentexopolymer particles in the microlayer and the subsequent production of agelatinous biofilm have implications on air–sea gas transfer and the partitioningof organic carbon in surface waters.