Detailed project information

In GEOTRACES we defined 6 key trace metals which, with additional metals Co, Ni, Ag, the Si isotopes and changes of CO2 will be investigated in our national IPY-GEOTRACES subprojects 1-7. The distribution and biological availability of Fe (sub 1) is strongly controlled by its physical-chemical speciation (sub 2) within seawater, where colloids and Fe-organic complexes are dominant actors. Cu (sub 4) at the cell wall of phytoplankton acts in reductive dissociation of Fe-organic complexes, hence facilitates Fe uptake and growth. This may partly explain the nutrient-type distribution of Cu in the oceans. The external sources of Fe into the oceans are either from above (dust) and below (sediments) and will be constrained by Al and Mn (sub 3) for aeolian dust input and sedimentary redox cycling sources, respectively. The Fe strongly enhances large diatoms, thus Fe (as well as Ag; sub 4), have via the siliceous frustules of these diatoms, a link with the Si cycle and isotope fractionation (sub 5). Diatoms in turn strongly control by their CO2 fixation the biological pump for uptake of CO2 from the atmosphere into polar oceans (sub 6). The increasing CO2 in polar ocean waters causes major shifts of seawater chemistry, including general acidification, and these shifts likely affect phytoplankton ecophysiology (sub 7), with key functions of metal Fe (sub 1-2) in the overall photosynthetic apparatus and Zn (sub 4) in carbonic anhydrase, where Cd and Co (sub 4) may substitute for Zn in the latter carbonic anhydrase.

Articles

• Et al., Prof. dr. ir. H.J.W. de Baar (2007). Whole season net community production in the Weddal Sea. Polar Biology. pp. 101-111
• Et al., Prof. dr. ir. H.J.W. de Baar (2009). Dissolved Aluminium and the silicon cycle in the Arctic Ocean. Marine Chemistry. pp. 176-195
• Et al., Prof. dr. ir. H.J.W. de Baar (2010). Speciation of Fe in the North East Atlantic Ocean.. Deep Sea Research. pp. 1444-1453
• Et al., Prof. dr. ir. H.J.W. de Baar (2011). Fluvial and hydrothermal input of manganese into the Arctic Ocean.. Geochimica et Comochimica. pp. 2393-2408
• Et al., Prof. dr. ir. H.J.W. de Baar (2011). Distributions and sources of dissolved iron over a prime meridian transect in the Southern Ocean. Deep Sea Research. pp. online
• ET al., Prof. dr. ir. H.J.W. de Baar (2011). Modulation of the Southern Ocean cadmium isotope signature by ocean circulation and primary productivity.. Earth and Planetary Science Letter. pp. 83-91

Proefschriften

• Dr. R. Middag Dissolved Aluminium and Manganese in the Polar Oceans. Rijksuniversiteit Groningen. promotiedatum 17-9-2010
• Dr. C.E. Thuróczy Physical and Chemical Speciation of Iron in the Polar Oceans. Rijksuniversiteit Groningen. promotiedatum 21-11-2011