Service Communautaire d'Information sur la Recherche et le Développement - CORDIS

Periodic Report Summary 1 - DISCOSAT (Determining the Impact of Seawater Chemistry on the Solubility of Atmospheric Trace metals)

Trace elements in the ocean (e.g. iron, manganese, cobalt, lead) can play important roles either as vital nutrients sustaining growth of algae (phytoplankton) or by reducing growth of organisms when these elements exceed toxic concentrations. A major pathway for trace elements to enter the ocean is via natural and man-made atmospheric particles (aerosols) that ‘rain out’ or settle into the ocean surface, the zone most populated by marine plants and organisms. The DISCOSAT project aims to assess whether the predicted changing climate and ocean chemistry over the next century (e.g. changes to acidity, oxygen, temperature, organic molecules) will affect the amount of these trace elements dissolving into the ocean. This is important as major changes of this kind could lead to ecosystem changes in vast regions of the ocean, favouring the survival of certain marine plants and animals.

The work of the Fellow (Dr Ussher) has focussed on sampling aerosols over a period of 2 years, at sites in the North Atlantic Ocean (Bermuda, Ireland and South West England) that receive winds containing aerosols representative of those falling in the ocean. Results of simulation experiments of these aerosols dissolving into seawater under future seawater chemistry conditions have shown that changes to the dissolution of the trace elements tested (Fe, Mn, Pb, Cu, Co) are unlikely to be devastating to the ecology of the ocean. Regardless of the pH, oxygen and temperature extremes, the dissolving time of metals is generally low (i.e. less than 10 minutes) and no significant changes to the quantities of the metals dissolving have been observed that would affect marine phytoplankton. However, major changes are evident depending on: the origins of aerosols being man-made (e.g. soot, ash) or natural (e.g. fine weathered dust), the global weather patterns (e.g. wind directions, pressure systems) and whether there are organic molecules (strong chelates or ligands) in the ocean that stabilise the dissolved metals in seawater.

The project has involved state-of-the-art sampling, processing and analytical techniques. Highlights include the development and use of mass spectrometry techniques that allows the separation of trace metals from seawater leaches prior to analysis, allowing very sensitive detection of concentrations down to parts per trillion concentrations (i.e. 1 g in 1,000,000 tonnes of seawater). The Fellow has benefited from the project by establishing his research agenda at the University of Plymouth and inheriting clean room laboratory space as well as continuation and establishing of collaborative links with the Bermuda Institute of Ocean Sciences and National University of Ireland, Galway. Thus far, Dr Ussher has seized the opportunity to train and supervise four PhD students (UK and EC funded). He is the main supervisor for three of these students, one of which was made possible by part funding from the Career Integration Grant. The grant has also allowed attendance of the fellow and his students at 8 scientific conferences and meetings and facilitated visits to Bermuda, Ireland and local sampling sites for fieldwork. One major scientific paper on the topic of marine trace elements has already been published by the fellow (as corresponding author) with two more as a co-author and a further two are in preparation.

The prospects of the research career development and re-integration of the Fellow are excellent as demonstrated by completion of probationary period as a lecturer and now being ready to apply for Reader (Assistant Professor) at Plymouth University, which is a major mid-career threshold in UK system.

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United Kingdom


Life Sciences