Details of Award
NERC Reference : NE/C517192/1
Air-sea OVOC fluxes: Seawater sources/sinks and role of the microlayer.
Grant Award
- Principal Investigator:
- Professor PD Nightingale, Plymouth Marine Laboratory, Plymouth Marine Lab
- Co-Investigator:
- Professor P Liss, University of East Anglia, Environmental Sciences
- Co-Investigator:
- Dr S Turner, University of East Anglia, Environmental Sciences
- Co-Investigator:
- Professor D Oram, University of East Anglia, Environmental Sciences
- Grant held at:
- Plymouth Marine Laboratory, Plymouth Marine Lab
- Science Area:
- Marine
- Atmospheric
- Overall Classification:
- Marine
- ENRIs:
- Global Change
- Science Topics:
- Environmental Microbiology
- Biogeochemical Cycles
- Ocean - Atmosphere Interact.
- Climate & Climate Change
- Abstract:
- Oxygenated volatile organic compounds (OVOCs) are a class of chemicals that include methanol, ethanol, ethanal (acetaldehyde), propanal (propionaldehyde), propanone (acetone) and butanone (methylethylketone). These gases are thought to play an important role in the chemistry of the troposphere, the part of the atmosphere closest to the earth's surface. In particular, OVOCs are believed to be important in the oxidant photochemistry of the troposphere by removing reactive nitrogen oxides and by acting as a source of radicals. It has been known for about ten years that formaldehyde is abundant in the marine troposphere and that its main source is probably via the oxidation of methane. However, it is only recently that the presence of a range of other OVOCs at significant concentrations has become evident. Researchers have shown that methanol is the dominant OVOC in the troposphere. The role of the oceans in global budgets of OVOCs remains largely unexplored. There are few seawater data available with which to determine the direction of air-sea fluxes, let alone their magnitude. Indeed there is only one set of data on oceanic methanol concentrations that was published only two weeks ago. Investigators have therefore attempted to predict the air-sea flux of OVOCs by interpretation of tropospheric data. The small number of studies published suggest that ethanal and propanal possess large oceanic sources but the direction (and magnitude) of the flux of methanol and acetone varies. Little progress will be made in reducing these uncertainties until more measurements of OVOCs in seawater are made. One of the main aims of this work is therefore to develop an analytical system for the measurement of selected OVOCs in air and seawater. We will use this equipment to participate in ship-based field experiments in different parts of the oceans to obtain more measurements of OVOCs in seawater and in the air. We will then use these data to calculate the direction and magnitude of the air-sea flux of OVOCs over a range of spatial and temporal scales. As might be expected, rather little is known about how OVOCs are produced and/or consumed in seawater. There is evidence that formaldehyde, ethanal and propanal are produced photochemically, with strong diurnal variations being observed, Indeed the concentrations of ethanal and acetone in the sea surface microlayer (the top 1mm of the sea), were found to be an order of magnitude greater than the bulk seawater. This enrichment meant that the flux of these compounds was from sea to air, whereas use of bulk water measurements would have led to fluxes in both directions. Production of methanol by phytoplankton has been suggested as have bacterial sources via transformation of algal products. The bacterial consumption of methanol via a common enzyme (methanol dehydrogenase) has also been proposed. Indeed, it has been hypothesised that a combination of a possible air to sea flux of methanol, together with in-situ production, could be sustaining some species of organisms throughout the surface ocean. As part of this project we will also measure OVOCs close to and in the sea surface microlayer to see if there are any significant difference in concentrations. We will also conduct experiments to test for photochemical and biological sources and sinks of these compounds in seawater and in the sea surface.
- Period of Award:
- 1 Nov 2005 - 31 Oct 2009
- Value:
- £156,555 Lead Split Award
Authorised funds only
- NERC Reference:
- NE/C517192/1
- Grant Stage:
- Completed
- Scheme:
- Directed Pre FEC
- Grant Status:
- Closed
- Programme:
- SOLAS
This grant award has a total value of £156,555
FDAB - Financial Details (Award breakdown by headings)
| Total - Staff | Total - T&S | Total - Other Costs | Total - Indirect Costs | Total - Equipment |
|---|---|---|---|---|
| £81,193 | £5,205 | £20,822 | £37,350 | £11,985 |
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