Cruising toward climate prediction

13 January 2012

A team of scientists led by Professor Gideon Henderson, Director of the Oxford Martin School’s 21st Century Ocean Institute, has set sail across the South Atlantic to investigate the ‘micronutrient’ metals that affect marine life and global climate.

Aboard the RRS James Cook, Professor Henderson, along with scientists from eleven institutes representing four countries, set out from Port Elizabeth in South Africa on 24 December. They will travel along 40°S from Cape Town to Montevideo, Uruguay, arriving on January 27.

The expedition is part of an international collaborative project, called GEOTRACES, which is designed to study all major ocean basins over the next decade. Henderson and his team have two main objectives. Firstly, to better understand controls on life and the carbon cycle in the ocean, improving our knowledge of the distribution and cycling of micronutrients. Micronutrients are a range of metals, present at low concentrations in seawater, which are required by ocean life. Of these micronutrients, the most prominent is iron which is known to be the major limitation on life in large areas of the ocean. Other micronutrients, such as zinc and cobalt, are also essential for critical biological processes.

Secondly, they will be calibrating critical paleoproxies (chemical measurement in sediments that are used to determine past climates). Paleoclimate records derived from such sediments enable scientists to assess the range of possible climates on Earth and the mechanisms that cause climate to change. This paleoclimate work is of fundamental importance to the accurate prediction of future climate. These proxies, if accurately calibrated, will provide information about the pattern and rate of past ocean circulation, and about the composition, flux and nutrient utilisation of past biological productivity (which sets the removal of carbon from the atmosphere). They therefore have tremendous potential to inform us about the role of the oceans in past climate, both through the transport of heat and carbon.

Professor Henderson’s team is funded by NERC as the UK-GEOTRACES Consortium.

GEOTRACES is an international programme which aims to improve the understanding of biogeochemical cycles and large-scale distribution of trace elements and their isotopes in the marine environment. Scientists from approximately 30 nations have been involved in the programme, which is designed to study all major ocean basins over the next decade.

Map courtesy of GEOTRACES. In red: Planned Sections. In yellow: Completed Sections. In black: Sections completed as GEOTRACES contribution to the IPY (International Polar Year).