Effects of ocean acidification on the interrelations of the trace metals to climate change

• Applicant: Dr. Linn J. Hoffmann
• Subject Area: Oceanography
• Term: from 2008 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 80934170

Trace metal bioavailability influences growth, photosynthetic efficiency, macronutrient consumption, as well as species composition of the marine phytoplankton community. Since trace metal speciation is sensitive to seawater pH it is likely that ongoing ocean acidification will affect the bioavailability of trace metals and will therefore have major implications for the trace metal chemistry and phytoplankton productivity in the future ocean. The project proposed here combines a chemical and a biological approach to investigate these interrelationships. The chemical part concentrates on the effect of decreasing seawater pH on the speciation and interrelationship of the biologically-active trace metals cadmium (Cd), iron (Fe), and zinc (Zn) in Southern Ocean waters. The biological part aims to investigate the effect thereof on primary production, species composition, and phytoplankton elemental composition with implications for carbon cycling and export. Both parts are again interconnected by investigating biological feedback mechanisms on trace metal speciation. This project will be closely linked into a project at the host institution that aims to calibrate the cadmium paleo-proxy for PO4 concentrations in seawater. The Cd:PO4 relationship is complex and thought to be affected by Cd utilizing biota as well as by the chemistries of Fe and Zn, and seawater pH.

• DFG Programme: Research Fellowships
• International Connection: New Zealand
• Host: Professor Dr.-Ing. Keith Hunter