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Marine Systems: from single cells to global biogeochemical cycles.

We are specifically interested in identifying and understanding at a systems level how phytoplankton communities and processes affect the chemical composition of organic compounds in the marine environment and how these compounds in-turn influence microbial and phytoplankton ecology.


Projects
A systems biology approach of diatom response to ocean acidification and climate change”

The oceans contribute 40--50% of the total photosynthesis on Earth driving the "biological pump" in the surface oceans, which exports carbon to the deep sea where it is sequestered. If the pump stops, the concentration of CO2 in the atmosphere would double. The world oceans are predicted to decrease 0.5 pH units by 2050 as a result of increasing atmospheric CO2 due to anthropogenic activity. The goal of this research is to understand the impact of these environmental perturbations on the contribution of diatoms to carbon cycling using a model system. Diatoms are the most productive phytoplankton group in the world oceans accounting for about 40 percent of the marine primary production, they form the basis of food webs in coastal and upwelling systems, support important fisheries and have a major role in carbon as well as silica cycling. In this work we focus on the influence of ocean acidification and high temperature stress on carbon cycling. Specifically, we are characterizing - at molecular and cellular levels using a systems approach - the influence of ocean acidification and temperature stress on carbon fixation in a model diatom “Thalassiosira pseudonana”.

 

Arctic Systems

Marine microgels: A microlayer source of summer CCN in high Arctic open leads

There is no region on earth where climate change is manifesting faster than it does in the Arctic. Models projecting future climate are the most uncertain in this region. Global climate is intimately connected to variability in sea ice, open ocean biogeochemical cycling and circulation, atmospheric radiation, and clouds over the Arctic Ocean. The goal of this research is to understand the influence of marine biological sources of aerosol particle production or growth. Specifically we focus in understanding the sources of microgels to gain a mechanistic understanding of the CCN (cloud condensation nuclei) formation and bio-radiative coupling.

 

Phytoplankton, Archaea Interactions

Phytoplankton produce 50% of total global organic carbon (C), and Archaea account for 40% of the microbial biomass in the world oceans, and 20% of the total biomass however their interaction is not well understood. We are interested in mechanistically understanding their coupled physiologies and cycling of nutrients in the context of the microbial loop paradigm and its implications to understanding the structure of complex aquatic ecosystems.