About
Pronunciation: jen-AN
Microbes play critical roles in carbon and nutrient cycling in every environment on Earth, especially in aquatic environments. The metabolic activities of these tiny, single-celled organisms mediate the biogeochemistry of marine and freshwater ecosystems from local to global scales, carrying out processes such as carbon fixation and sequestration, organic matter degradation, and controlling the balance of key nutrients like nitrogen and phosphorus. As the base of the food web, microbes are also important in structuring the composition of higher trophic levels. Understanding interactions within microbial communities and their influence on biogeochemical cycling is therefore necessary to predict whole ecosystem responses to anthropogenic climate change or pollution.
The central goal of my research is to understand how microbes mediate the production, fate and transformation of organic compounds in aquatic systems. As a microbial biogeochemist, I study the connections between microbial ecology and carbon and nutrient cycling in both modern and ancient environments, using a combination of organic biomarkers, genomic information, and stable isotope geochemistry to trace important microbial processes, especially those related to nitrogen uptake and transformation. I use both laboratory culture studies and field-based environmental observations, in order to connect cellular-level processes to large-scale geochemical trends in the environment.
Current projects/research interests include:
· Isotope fractionation patterns during the biosynthesis of nitrogen-containing biomarkers (e.g. chlorophyll, amino acids)
· Influence of nutrient sources, concentrations, and stoichiometry on phytoplankton community composition in marine and freshwater ecosystems
· Role of nitrogen in the presence, persistence, and/or toxicity of cyanobacterial harmful algal blooms
· Production and cycling of dissolved organic nitrogen in freshwater ecosystems
· Mutualistic relationships between phytoplankton and heterotrophic bacteria and the impact on microbial community structure and function
