Details of Award
NERC Reference : NE/C517168/1
Roles of DMSP and GBT in protection from photoinhibition/photoxidative stress and consequences for DMS and NH3 production.
Grant Award
- Principal Investigator:
- Dr S Archer, University of Essex, Biological Sciences
- Co-Investigator:
- Professor N Baker, University of Essex, Life Sciences
- Co-Investigator:
- Professor CA Llewellyn, Swansea University, College of Science
- Co-Investigator:
- Professor R Geider, University of Essex, Life Sciences
- Co-Investigator:
- Professor GJC Underwood, University of Essex, Life Sciences
- Grant held at:
- University of Essex, Biological Sciences
- Science Area:
- Marine
- Earth
- Atmospheric
- Overall Classification:
- Marine
- ENRIs:
- Global Change
- Science Topics:
- Environmental Microbiology
- Biogeochemical Cycles
- Ocean - Atmosphere Interact.
- Climate & Climate Change
- Abstract:
- This proposal addresses a highly topical issue: how biology in the oceans affects the atmosphere and hence our climate. Gases that are produced by the plankton in the oceans and are emitted to the atmosphere, have an important climate regulating function as they are the basis for aerosol and cloud production. As the oceans cover so much of the globe the impact these processes have on the atmosphere far from land plays a major part in determining Earth's climate. Two of the important gases in this respect are dimethylsulphide ((CH3)2-S) and ammonia (NH3) particularly because they react to enhance aerosol formation. We will focus on the processes that control their production in the oceans. These gases are the product of the breakdown of organic compounds synthesised by phytoplankton. One intriguing class of compounds are nitrogen- and sulphur-based osmolytes. In fact the osmolyte dimethylsulphoniopropionate (DMSP) is the only source of DMS and a very similar N-containing compound, glycine betaine (GBT) breaks down to NH3. These osmolytes are produced in varying amounts sometimes by the same species of phytoplankton sometimes not. In order to predict how much DMS and NH3 are being produced from these osmolytes and how climate change might impact on this production, we need to know what controls the production of the osmolytes themselves. At present this is largely unclear. In addition to helping to maintain the osmotic balance and constant environment within phytoplankton cells they may have a role as photoprotective mechanisms. In the surface oceans, phytoplankton are exposed to varying levels of sunlight and ultraviolet radiation (UV) on a short time scale (vertical swirling), through seasonal changes and of course in different regions. Their photosynthetic apparatus works most efficiently if it is supported by systems that allow it to compensate for these changing light levels and to keep working at high efficiency and that counteract the harmful effects of UV. DMSP production and its conversion to DMS has been shown to increase when phytoplankton are exposed to UV in laboratory environments. The chemicals themselves have been shown to soak-up harmful radicals of the type that are produced when the photosynthetic apparatus of cells is over-stretched in high sunlight or UV. We know that GBT production in terrestrial plants helps to combat stress to the photosynthetic apparatus in times of drought, cold and high light. We hypothesise that DMSP and GBT act as protective mechanisms to photosynthesis in phytoplankton and that this function explains how much they are produced and when. We plan to examine in detail the photoprotective roles of DMSP and GBT, workout how these roles impact on the levels of production of the two compounds on varying timescales and in different parts of the oceans and finally, try to decipher what impact this may have on the production of the climate-active gases DMS and NH3. In order to do this we have combined the expertise of a group of photosynthesis-experts at University of Essex with a group at Plymouth Marine Laboratory who study the production of gases in the oceans. We will use highly sophisticated biophysical techniques to examine the efficiency of activity of the photosynthetic apparatus of phytoplankton and the levels of stress it is under at differing light levels. At the same time we will measure the intracellular concentrations of DMSP and GBT and the breakdown products, including DMS and NH3 to see how they change in relation to the stress that the photosynthetic apparatus is under. To support these measurements we will also measure the changes in two other processes that we know act as photoprotective mechanism in phytoplankton. What will we actually do? We will grow a range of phytoplankton species in single-species cultures in the laboratory where detailed experiments will be carried out. We will conduct an annual study in the waters of the Western English Channel to ex.........
- Period of Award:
- 1 Oct 2005 - 30 Jun 2009
- Value:
- £187,240 Split Award
Authorised funds only
- NERC Reference:
- NE/C517168/1
- Grant Stage:
- Completed
- Scheme:
- Directed Pre FEC
- Grant Status:
- Closed
- Programme:
- SOLAS
This grant award has a total value of £187,240
FDAB - Financial Details (Award breakdown by headings)
| Total - T&S | Total - Staff | Total - Other Costs | Total - Indirect Costs | Total - Equipment |
|---|---|---|---|---|
| £3,954 | £91,468 | £18,184 | £42,076 | £31,562 |
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