Iron limits primary productivity in 40% of the oceans. Its accurate determination is thus critical to understanding the functioning of marine ecosystems and their role in moderating Earth's climate. Recent findings indicate that serious discrepancies exist in iron concentrations obtained using different analytical methods. These discrepancies are believed to be due to the lability of organic and colloidal iron species to extraction by adsorbent preconcentration resins. This project will design and synthesise a range of functionalised resins for the selective extraction of iron species from seawater, advancing our knowledge of its bioavailability and leading to the generation of class-specific analytical methodologies.

Participants:

Andrew Bowie

Iron deficiency limits phytoplankton growth in the Southern Ocean. Processes controlling iron availability include uptake into phytoplankton, loss in sinking particles, and recycling by bacteria, but there is little information on the iron contents of these materials. Novel methods will be applied to collect and analyse iron in Southern Ocean particles. The results will be used to aid our understanding of the role of iron in structuring ocean ecosystems, thereby mediating carbon transfer to the deep sea and influencing atmospheric carbon dioxide levels.

Participants:

Andrew Bowie, Tom Remenyi

Inter-laboratory and shipboard calibration exercises are currently underway for the international standardisation of sampling, filtration and analytical methods for the determination of trace elements in seawater. This will enable the marine scientific community to correlate observations of trace element concentrations, and distinguish between environmental variability, analytical data quality and measurement drift.

Participants:

Andrew Bowie

This project will advance our understanding of the role aeolian dust deposition plays in supplying trace elements to the remote open-ocean, and thus its effect on the marine productivity. Aluminium distributions will be measured at sea using a flow injection - fluorescence analytical method, and surface water concentrations used as a tracer of dust deposition.

Participants:

Juliette Tria, Andrew Bowie, Edward Butler, Paul Haddad

In this project, selenium (and other metalloid elements arsenic and antimony) will be studied in the Southern Ocean, to improve our knowledge of their role as trace nutrients for micro-algae, and therefore as a possible regulator of carbon cycling in these waters.

Participants:

Bronwyn Wake, Andrew Bowie, Edward Butler, Paul Haddad

Determination of an adverse human impact on the environment requires the establishment of assessment procedures. This project contributes towards the establishment of Antarctic sediment quality guidelines by studying contaminated and pristine sediments from the Windmill Islands, Antarctica using simple physical and wet chemical techniques.

Participants:

Anne Palmer, Ian Snape, Ashley Townsend (Central Science Laboratory), Andrew Seen

Impacted and pristine marine sediments from the Windmill Islands, Antarctica are being studied using highly sophisticated techniques to determine the chemical form of selective metals. This study will further our understanding of metal transport dynamics, bioavailability and toxicity of metals in the Antarctic marine environment.

Participants:

Anne Palmer, Ivan Kempson, Ian Snape

This project will alter the binding mechanism of conventional Diffusive Gradient in Thin film (DGT) devices to selectively target individual metals while also providing spatial discrimination. This will enable in situ measurement of labile metal concentrations in both seawater and sediment porewaters to further our understanding of metal bioavailability and toxicity in the marine environment.

Participants:

Russell McGifford, Paul Haddad, Andrew Seen, Anne Palmer