Until recently, scientists studying the biogeochemistry of the ocean have presumed that the elemental composition of planktonic organisms -- including algae, protozoa and mesozooplankton -- could be conveniently described using something called the Redfield Ratio. This broadly applicable assumption has proven immensely useful to understanding how biogoechemical cycles of different elements are linked. However, even A.C. Redfield early on realized that algae can vary substantially in elemental composition depending on the availability of key nutrients. Some of this variation reflects physiological responses to ambient conditions, like nutrient levels, temperature and light. However, some variation also represents robust inter-specific differences in average elemental composition. Moreover, how the elemental composition of an organism changes in response to environmental gradients varies among species. If organisms with particular Si or Fe contents are favored under different conditions, such interspecific differences in elemental composition could lead to substantial seasonal or regional differences in biogeochemical variables like algal biomass and export. Our lab is interested in ...

1) Quantifying inter and intra-specific variation in elemental and biochemical composition of microplankton.

2) Assessing the implications of this variation for biogeochemical cycles and ecological interactions.

3) Linking ecological process to variation in biogeochemical cycling of key nutrient elements.