Dimethyl sulphide

Dimethyl sulphide (DMS) is a climate-active gas that is a breakdown product of a compound (DMSP), which is synthesised by several phytoplankton species. As a nuclei for cloud condensation, DMS is thought to play a significant role in regulating the Earth’s temperature.

 

Understanding how much DMSP is produced, when and why, should help us to predict how DMS emissions will change in the future and impact upon the Earth’s temperature. However, modelling the impact of DMS emissions is currently hampered by a lack of knowledge of the processes regulating DMS and its precursor DMSP. For example, it is not yet understood why some phytoplankton invest as much as 10% of their resources in DMSP production whilst their taxonomic cousins, sharing the same patch of ocean, produce none.

 

PML, in collaboration with colleagues from Essex University and the Netherlands, has made a major step forward in understanding the physiological role of DMSP. Experiments on SOLAS cruises have questioned current views that DMSP acts primarily as an anti-oxidant and that its production is regulated by physiological stress. The results suggest that DMSP may have an alternative photo-protective role, which will help to improve the capability to predict DMS emissions.

 

Studies of a similar compound in terrestrial plants (GBT) have shown it to be used for photosystem repair. PML aims to determine whether DMSP plays a similar physiological role in phytoplankton and how this regulates their relative production.


Projects

  • European Project on OCean Acidification (EPOCA)
    EPOCA Svalbard experiments investigated concentrations of DMS produced by phytoplankton under higher CO2.
  • European Regional Seas Ecosystem Model (ERSEM)
    ERSEM was developed in the 1990s to simulate carbon and nutrient cycling and ecosystem response in European shelf seas and PML was part of the original consortium which developed it. Since the end of the original programme PML scientists have been developing the original model and developing applications in a number of fields.  ERSEM has been adapted to describe the planktonic production of biogenic sulphur compounds and their subsequent biological modification into climatically active gases.
  • Surface Ocean Lower Atmosphere Study (SOLAS)
    PML has organised a series of six cruises onboard the RRS Discovery as a contribution to the UK SOLAS programme one of which looked at DMS emissions and air-sea transfer of DMS at storm-force winds. The international SOLAS programme aims to achieve quantitative understanding of the key biogeochemical-physical interactions and feedbacks between the ocean and atmosphere, and of how this coupled system affects and is affected by climate and environmental change.