Sea foams are ephemeral hotspots for distinctive bacterial communities contrasting sea-surface microlayer and underlying surface water

• Published in: FEMS microbiology ecology Vol. 97; no. 4; p. 1
• Main Authors: Rahlff, Janina, Stolle, Christian, Giebel, Helge-Ansgar, Mustaffa, Nur Ili Hamizah, Wurl, Oliver, P. R. Herlemann, Daniel
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.04.2021
• Subjects: Abundance; Bacteria; Bacteria - genetics; Carbon cycle; Community composition; Ecology; Editor's Choice; Environmental aspects; Foams; Indonesia; Interface stability; Microbial colonies; Microbiology; Mikrobiologi; North Sea; Oceans; Oceans and Seas; RNA, Ribosomal, 16S - genetics; rRNA 16S; Seawater; Surface microlayers; Surface water; Water; Water depth; North Sea; Indonesia; Germany; air–sea interface; surfactants; neuston; particles; 16S rRNA amplicon sequencing
• ISSN: 0168-6496; 1574-6941; 1574-6941
• DOI: 10.1093/femsec/fiab035

ABSTRACT The occurrence of foams at oceans’ surfaces is patchy and generally short-lived, but a detailed understanding of bacterial communities inhabiting sea foams is lacking. Here, we investigated how marine foams differ from the sea-surface microlayer (SML), a <1-mm-thick layer at the air–sea interface, and underlying water from 1 m depth. Samples of sea foams, SML and underlying water collected from the North Sea and Timor Sea indicated that foams were often characterized by a high abundance of small eukaryotic phototrophic and prokaryotic cells as well as a high concentration of surface-active substances (SAS). Amplicon sequencing of 16S rRNA (gene) revealed distinctive foam bacterial communities compared with SML and underlying water, with high abundance of Gammaproteobacteria. Typical SML dwellers such as Pseudoalteromonas and Vibrio were highly abundant, active foam inhabitants and thus might enhance foam formation and stability by producing SAS. Despite a clear difference in the overall bacterial community composition between foam and SML, the presence of SML bacteria in foams supports the previous assumption that foam is strongly influenced by the SML. We conclude that active and abundant bacteria from interfacial habitats potentially contribute to foam formation and stability, carbon cycling and air–sea exchange processes in the ocean. Floating foams at the oceans’ surfaces have a unique bacterial community signature in contrast to sea-surface microlayer and underlying water.