Department Surface Waters - Research and Management

The biogeochemical cycling of trace metals is fundamentally connected to biological productivity because trace metals are micronutrients for phytoplankton. Due to fractionation during biological uptake, trace metal stable isotope composition is also influenced by biological productivity. Consequently, metal stable isotopes in sediment records are emerging as potential tools to reconstruct biological productivity in the past. Such tools, called paleoproxies, help to understand connections between global climate and surface water biogeochemistry in the past. The understanding of biogeochemical responses to past climatic shifts, derived from paleoproxies, can then help forecast impacts of ongoing climate change.

This project connects the modern and past biogeochemical cycling of trace metals and their isotopes. Stable isotope signals will be followed through modern aquatic systems, from uptake in surface waters, export to depth, and finally sedimentation. This will quantitatively constrain connections between isotope records in sediments and surface water biogeochemical cycling. Promising new stable isotope proxies will then be compared to existing tracers over time in biogenic sediments. These data will help evaluate the potential of stable isotopes as proxies, and will guide future stable isotope paleoproxy research.