Expertise
My research program centers on the study of the transformations of organic matter in atmospheric and aquatic environments. Some general areas of interest include:
- Organic-metal interactions
- Transformations of organic matter in freshwater and marine sediments
- Chemical processes at interfaces such as the sea-surface microlayer and on the surface of manganese oxides
- Photochemical transformations of dissolved organic matter (DOM)
- The role of photochemically-generated DOM in planktonic food web dynamics
- Atmospheric transformations of organic matter and their impact on surface water biogeochemistry
- Antarctic photochemistry
- Development of trace analytical techniques suitable for environmental analyses
I am quite interested in the marine sulfur cycle, particularly in the role of dimethyl sulfide (DMS) photochemistry on the dynamics of the oceanic DMS cycle.
Another area of research that I have pursued is on the role of manganese oxide particles in the oxidation of DOM in aquatic systems and sediments.
Research has been conducted in my laboratory to understand the role of free radicals in the photochemical oxidation of organic matter in clouds, freshwater, and seawater.
In this context, there are several broader questions that I address through my research:
- Is sunlight photolysis an important removal mechanism for biologically refractory carbon in natural waters?
- Do photochemical processes represent an important mechanism for the non-biological production of biologically labile organic substrates?
- Can organic carbon be a limiting nutrient to bacteria, especially in Antarctic waters as previously suggested by other investigators?
- Will increased UV-B radiation (280-320 nm) stimulate bacterial production by increasing the amount of carbon available to bacteria through photo-oxidative processes?
- Is the photochemical production of some species (e.g., the OH radical, hydrogen peroxide) inhibitory to plankton?