Glider Shelf-Edge Nutrient Exchange (GliSENEx)

Lead Research Organisation: National Oceanography Centre
Department Name: Science and Technology


The shelf edge represents the boundary between the shallow coastal seas (<200 m deep) and the deep ocean, where the exchange of water, nutrients and other substances have important implications for shelf sea primary production, for the export of atmosphere derived carbon dioxide to the deep ocean interior and for the overall health of the coastal environment. Satellite reconnaissance routinely reveals the shelf edge to be a region of enhanced chlorophyll concentration and thus indicative of a region with high rates of primary production relative to the shelf interior. The shelf edge is thus a region with a key ecological role. This proposal will examine the fate of nitrate fluxes at the Malin Shelf, and their relationship to chlorophyll and primary production. The merging of novel nutrient sensors with glider technology (to assess the flux) and leading-edge satellite algorithms (to estimate chlorophyll concentration and primary production rates) to carry out this project will, more generally, produce a robust demonstration of the ability of gliders to be used for complex multidisciplinary biogeochemical studies.

Planned Impact

The proposed project will exploit links to other projects and entities to allow it to disseminate its results to maximum effect:

- Links to the FASTNEt programme, particularly via a shared cruise (see Inall letter of support), will ensure that the proposed research (and student) exploits links to this major UK research programme with a similar focus. Derivation of nitrate fluxes at the Malin Shelf break during periods when the FASTNEt programme is not at sea will also ensure widespread interest in the data within the UK oceanographic community and provide a natural bridge to future links, and interactions, with the NERC Shelf Sea Biogeochemistry programme.

- Products produced by the remote sensing group at Plymouth Marine Laboratory are widely used by a range of international researchers and organisations. Thus the refinement of algorithms and models of primary production in shallow coastal seas and their boundaries with deep water with different optical characteristics will be rapidly and diffusely propagated to the wider remote sensing community through the PML group.

- The Met Office will benefit from an unprecedented simultaneous source of physical and biogeochemical data at a time when they are embarking on development of data assimilation in their operational ecology models. There is considerable interest in this Met Office initiative, both scientifically and for the purpose of addressing the monitoring component of the Marine Strategy Framework Directive. This project will consequently also be of interest to Defra, Cefas, Marine Scotland and other agencies who have responsibility for the Shelf Seas around the UK.
Description Primary production is the conversion of carbon dioxide into living matter by plants. In the ocean this is carried out by phytoplankton. It is important to be able to measure marine primary production (PP) as cumulatively they fix as much carbon each year as all land plants combined. We can measure PP by taking water samples but this is time-consuming and only possible when we can get ships out, so rare in winter. We can measure it using satellites but they only see the top few metres of the water. Using gliders allows us to measure primary production up to 100m deep in to the ocean at any time of year.
Using this approach in conjunction with another novel development that allows us to estimate how quickly water is brought up to the surface we have also managed to build a budget for nitrogen in the surface ocean. Nitrogen fuels growth by phytoplankton, the marine plants that absorb as much CO2 out of the atmosphere as all land plants. We have shown for the first time that a major supply of nitrogen comes from ephemeral circulations associated with eddies and fronts, the ocean analogies of weather.
Exploitation Route Autonomous sensing and environmental monitoring
Sectors Aerospace, Defence and Marine,Agriculture, Food and Drink,Environment