Biogeochemical Cycles & Climate

Many researchers at PCIGR work on quantifying the biogeochemical cycles of carbon and related elements in marine environments. As the marine biogeochemical cycle of carbon dictates the level of atmospheric CO₂, this research has direct implications for societal concerns about climate change. The rapid increase in anthropogenic CO₂ and other greenhouse gases in the atmosphere during the last century is placing a strain on Earth’s climatic system that is unprecedented in human history.

Large uncertainties in ocean and climate model predictions still exist, and there is increasing urgency to better understand the underpinning of past climate, better predict future climate, and develop solutions to mitigate the rise of atmospheric CO₂.

Examples of research include:

– understanding cellular requirements and acquisition mechanisms of Fe and other bioactive metals (e.g., Cu, Cd) in marine phytoplankton to constrain the cycling of trace elements in seawater;

– measuring metal isotopes (e.g., Fe, Si, Pb) in seawater to study their sources and biological cycling in the ocean;

– reconstructing oceanic meridional overturning circulation and resulting heat transport to assess the sensitivity of global climate to ocean circulation;

– measuring major and trace elements, and ²³⁰Th, He, O, N and C isotopes in marine sediments to establish the past efficiency of the ocean to naturally sequester atmospheric CO₂; and

– developing new isotopic tracers (Si, Cd, Cr, Mo, Cu, Zn, Fe) to evaluate past changes in ocean productivity, nutrient cycling, redox conditions and anthropogenic impact.

Below are some snapshots of the projects that fall under this research theme.

Researchers:
Maldonado, Maria (Maite)
Pakhomov, Evgeny
Francois, Roger
Orians, Kristin
Dipple, Greg
Tortell, Philippe
Weis, Dominique
Calvert, Steve