The research carried out by Keith Weston consists mainly of biogeochemical studies of the marine and estuarine environment.
Tom Bell studied the marine biogeochemical cycling and sea - air exchanges of sulphur and nitrogen
during his PhD research.
He is now the Project Integrator for SOLAS.
Alex Baker's interests lie in the transportation and reactivity of iron and iodine in the marine and atmospheric environments.
Megan French is working on the role of silicon as a nutrient in the oceans.
Laura Bristow is interested in the cycling of nutrients in the North Sea.
- North Sea Studies
- Our research involves trying to understand the sources, transport and cycling of nutrients (nitrogen, phosphorus and silicon) through coastal waters and ultimately their fate. We have extensively studied their behaviour in estuaries, showing that currently UK estuaries tend to transport rather than transform or store nutrients, and indeed many contaminants, in part due to the lack of intertidal areas to provide sedimentation and biogeochemical reaction sites. We have also undertaken programmes to quantify the atmospheric inputs to coastal seas and compare the importance of this source to the riverine input. We have more recently worked extensively in the coastal North Sea region and to a lesser extent in other parts of the North European continental shelf, addressing the fate of the nutrients beyond the estuaries. We measure standing stocks of the nutrients and rates of biological uptake of carbon and nitrogen and other parameters to derive budgets to describe sources and sinks. Much of this work is done in cooperation with colleagues at the CEFAS Laboratory in Lowestoft. Current new research directions include studies of organic nutrients (DON and DOC) and the application of natural isotope abundance measurements to characterise C and N sources and cycling.
- Coastal Management
- Our work on estuarine nutrient transport has led us to realise that the management of estuaries is central to their biogeochemical function. In particular, land reclamation and sea-defence work in estuaries in the southern UK has removed vast amounts of intertidal areas such as mud flats, salt marshes and other wetlands. This has removed natural sea defences, valuable ecological habitat and the natural ability of estuaries to attenuate nutrient fluxes to the coastal seas. Indeed it seems likely that in the past estuaries such as the Humber and Wash were sinks for nutrients from the North Sea, while now they are sources, due to increased nutrient loading and loss of intertidal areas.
Global change pressure and particularly sea level rise is leading to changes in sea defence policy and in some cases to managed realignment where sea defences are moved back and marine habitats recreated. Together with Julian Andrews (ENV) and colleagues at CEFAS and environmental economists such as Kerry Turner (ENV) we have attempted to describe the biogeochemical value of the recreated wetlands in terms of carbon burial, contaminant trapping and nutrient cycling, so that these can be included in cost-benefit analyses of managed realignment schemes.
- Reduced sulphur and nitrogen studies
- It has long been established that the cycles of reduced nitrogen and sulphur in the surface of the open ocean are driven by biological processes. Reduced sulphur (DMS) and nitrogen (NH3) gases from the ocean can undergo chemical reactions to form particles in the atmosphere. In remote marine regions, these particles are composed of approximately equal amounts of nitrogen and sulphur species, which suggests that the elemental cycles in the surface ocean and lower atmosphere may be coupled. A greater understanding of this is particularly important as aspects of these cycles can potentially affect cloud water acidity (and hence processing within the cloud) and the flux of solar radiation reaching the ocean surface. Tom Bellís PhD research (supervised by Gill Malin, Tim Jickells, Alex Baker and Peter Liss) involved three cruises as part of the Atlantic Meridional Transect (AMT) project. This provided an excellent framework within which to interpret the DMS, NH3 and aerosol particle composition data that was collected. To discover more about his findings, please consult his thesis.
- In addition to these studies in the North Sea where human activity exerts considerable stress on the environment, we have a programme studying nutrient cycling in Antarctic coastal waters. Working with colleagues from the British Antarctic Survey (BAS) and the Open University under NERC AFI funding we have been engaged in a study of the cycling of heat, salt, carbon and nutrients in Marguerite Bay to the south of the BAS base at Rothera. We conduct regular year-round measurements at stations next to Rothera, and also use long term moorings with CTDs, current meters and sediment traps to describe the seasonal cycles of analytes of interest and use these data to develop quantitative budgets. Colleagues from the Universities of Cambridge, Oxford and Edinburgh are conducting a related programme investigating how the biogeochemical processes we describe are ultimately recorded in the sediment record. This is an utterly spectacular and challenging environment in which to work, and the hydrography of the region also provides a particularly good setting in which to develop quantitative budgets. The region is extremely biologically productive. Through winter ice prevents much biological activity, but as the ice breaks up extremely intense algal blooms take place throughout the summer. It seems likely that these contribute to the rich biological activity in this area, which is for instance an important nursery area for krill that provide food that sustains the whales of the Southern Ocean.
- Iron studies
- Our work focuses on the atmospheric inputs of iron to the surface ocean. Various studies have been carried out as part of the European Union funded project, IRONAGES, and this work continues through the SOLAS and Atlantic Meridional Transect programmes.
- Iodine studies
- This work is based on the measurement of dissolved iodine species in seawater samples and in rain and aerosol samples, and the measurement of organic iodine gases in seawater and air samples. We also work on the iodine metabolism of marine algae is in close collaboration with Gill Malin and other members of Prof. Peter Liss's group.
For more information, visit Alex's iodine pages.
This page was last updated in April 2008.