School of Natural and Environmental Sciences

Projects

UKSOLAS: The role of the bacterioneuston in air-sea gas exchange

Overview

The sea-surface microlayer (SML) is an important air-sea boundary less than 0.5 mm in depth with distinct biological, chemical and physical properties. SML microbial populations (the bacterioneuston) are distinct from those in underlying water and they metabolise a range of trace gases, modifying their ocean-atmosphere exchange rates. This project determined SML microbial diversity, abundance and activity and examined the potential role of the bacterionesuton in air-sea trace gas exchange. 

Project description

The sea-surface microlayer (SML) is a region only tens of microns thick at the air-sea interface but this important boundary has unique biological, chemical and physical properties that potentially may impact the global biogeochemical cycles of a suite of climate-active gases.  

Although SML microbial populations (the bacterioneuston) are now known to be quite distinct from those in sub-surface waters just a few centimetres below, our understanding of how the bacterioneuston impacts globally relevant processes at the air-water interface remains rudimentary. This reflects difficulties of sampling the SML and in determining its community structure via conventional microbiological techniques.

Marine bacteria almost certainly metabolise a range of organic compounds, trace gases (including carbon dioxide, methane, nitrous oxide, methyl bromide and dimethylsulfide) and organic sulfur compounds such as methanesulfonic acid (MSA) that may be enriched in the SML. In so doing, they modify, perhaps markedly, their ocean-atmosphere exchange rates.  

This project determined the diversity, abundance and activity of major groups of microorganisms in the bacterioneuston and examined their involvement in trace gas cycling by way of controlled gas exchange experiments in a custom-built laboratory facility.