Application of Flow Cytometry and Membrane Inlet Mass Spectrometry as Tools to Assess Dimethyl Sulfide Produced in Emiliania huxleyi (CHC108) Cultures

Dimethyl sulphide (DMS) is a key component in the global sulphur cycle with emphasized significance in areas away from anthropogenic sources. Phytoplankton produce DMS when under stress as a defence mechanism from abiotic and biotic influences such as high wind stress and grazing. E. huxleyi was used as the phytoplankton of choice because of the cosmopolitan nature of the species along with the more robust nature of the coccolith. DMS has a high diffusion rate in the atmosphere so immediately monitoring the levels in the water column has proven difficult especially when looking at continuous input flux. In this study, membrane inlet mass spectrometry was used to monitor DMS flux over varying periods of time along with a possible variation of DMS under Mass 47 which excludes one of the methyl groups under different stressors. This continuous observation allowed for the observation in minute changes over longer periods of time rather than using the snapshot method which looks at chemical concentrations at singular points in time. This novel technique can give insights to the response times of the phytoplankton to the changing environment in real time. The added stressors to the water column did result in an increase of DMS but the lag time to the addition and the visible increase in DMS did not follow the expected trend. Of the parameters tested here, the most likely to initiate DMS production is heavy metal loading and water column acidification