Details of Award
NERC Reference : NE/C508385/1
Assessment of bottom up control of Calanus finmarchicus production based on measured phytoplankton produc & satellite-based estimates of new produc
Grant Award
- Principal Investigator:
- Dr M Lucas, University of Southampton, National Oceanography Centre Southampton
- Co-Investigator:
- Professor R Sanders, University of Southampton, Sch of Ocean and Earth Science
- Co-Investigator:
- Dr J Allen, University of the Highlands and Islands, Research Office
- Co-Investigator:
- Professor SB Groom, Plymouth Marine Laboratory, Remote Sensing Group
- Co-Investigator:
- Dr M Moore, University of Southampton, National Oceanography Centre Southampton
- Co-Investigator:
- Dr GH Tilstone, Plymouth Marine Laboratory, Plymouth Marine Lab
- Science Area:
- Marine
- Overall Classification:
- Marine
- ENRIs:
- Natural Resource Management
- Global Change
- Biodiversity
- Science Topics:
- Biogeochemical Cycles
- Ocean Circulation
- Population Ecology
- Community Ecology
- Abstract:
- One of the most important zooplankton in the North Atlantic is Calanus finmarchicus, a primarily herbivorous crustacean about the size of a grain of rice, which is an important food resource for commercially important fish such as haddock, herring and mackerel. However, the numbers of Calanus have declined steadily over the last 40 years - and we need to understand why. Potential reasons for this include changing circulation patterns and/or changes in the abundance and distribution of their food; primarily the small single-celled and free-floating microscopic plants, the phytoplankton. From recent research cruises to the NE Atlantic during winter, spring, summer and autumn of 2001/2 we gathered information on the distribution and abundance of Calanus over the entire Irminger Basin. We also made routine measurements of phytoplankton pigments (eg. chlorophyll-a as a measure of biomass) and we enumerated the principal phytoplankton species. However, to determine whether Calanus are facing a food shortage, we need to estimate or measure phytoplankton production. We have done this, but only for two cruises (summer & autumn 2003) and over the limited area of the cruise tracks. We therefore lack spring and winter measurements of phytoplankton production as well as production rates over appropriate spatial and temporal scales. However, we can recover an estimate of spring bloom and winter phytoplankton production as well as scaling our estimates of production to year-round, basin-scale values of phytoplankton production from ocean colour satellite imagery. These values can then be incorporated into ecosystem models that describe the distribution of Calanus and the sensitivity of these populations to a variable food environment. Satellite-based estimates of primary production are dependent on establishing appropriate relationships between the light scattered back into space by particles (mostly phytoplankton) in the water column (which is what the satellite 'sees') and what amounts of phytoplankton are actually present in the water column. To do this, we will need to measure various indices of phytoplankton abundance and activity in the water and relate this to satellite observations. From this we can initially calculate phytoplankton biomass and then use measured relationships between biomass and productivity to reconstruct phytoplankton production rates, from space. Production rates estimated from space will then need to be validated with phytoplankton productivity measured in the sea. Once we have established reliable year-round and basin-scale phytoplankton production, this will provide an estimate of the available food for Calanus. We will use this information to assess whether the abundance of Calanus is controlled by the available food or by other mechanisms.
- NERC Reference:
- NE/C508385/1
- Grant Stage:
- Completed
- Scheme:
- Directed Pre FEC
- Grant Status:
- Closed
- Programme:
- Marine Productivity
This grant award has a total value of £26,215
FDAB - Financial Details (Award breakdown by headings)
| Total - T&S | Total - Staff | Total - Other Costs | Total - Indirect Costs |
|---|---|---|---|
| £1,338 | £16,336 | £1,026 | £7,514 |
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