Bryan Downing
Researcher
Hydrology
The U.S. Geological Survey
United States Virgin Islands
Biography
Research hydrologist at the USGS California Water Science Center, with a principle interest in studying aquatic organic matter (dissolved and particulate) and nutrients to better understand their impact on ecosystem functioning. involves the use of optical measurements (attenuation, absorbance, fluorescence and backscatter) to better understand complex biogeochemical cycling of organic matter and nutrients in rivers, estuaries and the coastal ocean. Measuring water quality using optical sensor technology represents a significant new direction in water quality research, where cycling of nutrients and organic matter can be measured in-situ, on time scales ranging from seconds to years. study goals is to help provide enhanced optical instrumentation and methodologies, to improve real-time measurements of nitrate, phosphate, fluorescent dissolved organic matter (FDOM), algal pigments (chlorophyll-a and phycocyanin - a common blue-green algae proxy) and detection of harmful algal blooms (HABs). Currently, my colleagues and I have developed a boat based, high speed mapping system that measures transects of nutrients, WQ, stable water isotopes (d2H and d18O) with GPS location at sampling frequencies of 1Hz in real time.
Research Interest
impact on ecosystem functioning,optical measurements (attenuation, absorbance, fluorescence and backscatter) to better understand complex biogeochemical cycling of organic matter and nutrients in rivers, estuaries and the coastal ocean
Publications
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BA Pellerin, BA Bergamaschi, RJ Gilliom, CG Crawford, J Saraceno, CP Frederick, BD Downing and JC Murphy. 2014. Mississippi River Nitrate Loads from High Frequency Sensor Measurements and Regression-Based Load Estimation. Environmental Science and Techology, dx.doi.org/10.1021/es504029c
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Fleck, J. A., Gill, G., Bergamaschi, B. A., Kraus, T. E., Downing, B. D., and Alpers, C. N., 2014, Concurrent photolytic degradation of aqueous methylmercury and dissolved organic matter: Science of The Total Environment, v. 484, p. 263-275
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Fichot, C. G., Downing, B. D., Bergamaschi, B. A., Windham-Myers, L., Marvin-DiPasquale, M. C., Thompson, D. R., & Gierach, M. (2015). High-resolution remote sensing of water quality in the San Francisco Bay-Delta Estuary. Environ Sci Technol. doi:10.1021/acs.est.5b03518
