My research is focused on the biogeochemical cycles of nutrients, especially Si, and the linkages between land and aquatic ecosystems. Massive amount of amorphous silica accumulates on land in soils from deposition of plant phytoliths and in lakes as diatoms delaying the export of weathering products from the landscape to aquatic ecosystems. I am interested in long-term trends driven by climate and nutrients and how ecosystems respond to changes in the drivers. I also use paleoecological techniques and analysis of long term monitoring data to help manage aquatic ecosystems.
Together with Jarone Pinhassi’s research group at the Centre for Ecology and Evolution in Microbial model Systems (EEMiS) at Linnaeus University we are investigating how the emergence and expansion of silica biomineralization in the oceans has affected the evolutionary competition for dissolved Si. We are interweaveing biogeochemistry & geology and aquatic microbiology & genomics in our new interdisciplinary research project from the Knut and Alice Wallenberg Foundation. We have identified three critically important time periods when large-scale changes in Si cycling occurred: 1) The transition from bacterial to eukaryotic marine primary productivity in the Proterozoic, 2) an exploration of the role of the three major groups of extant eukaryotic phytoplankton (diatoms, dinoflagellates and coccolithophores) with competition from cyanobacteria in changing oceanic DSi concentrations in the Mesozoic, and 3) the impact of changing dissolved Si inputs on the Cenozoic oceanic. We will utilize stable isotope measurements of Si to infer biosilicification in fossil material and undertake experimental microbiological investigations of key prokaryotes and silicifying eukaryotic phytoplankton groups. It is through this unique combination of the geological record coupled with experimental microbiological investigations of key prokaryotes and silicifying eukaryotic phytoplankton groups that we will achieve a new understanding of the functioning of the Earth’s oceans through geological time. Ultimately, such understanding is essential for interpreting how changes in environmental conditions will impact global climate and food webs into the future.
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