Scientist Emeritus
443-482-2285
Research Labs
Staff Profile
Biography
Research Interests
I study the effects of sunlight, especially ultraviolet radiation, on ecosystems and the environment. I mainly work in freshwater and marine systems focusing on the responses of the smallest organisms in those systems, the plankton. A long term project has been studying the effects of increased UV-B due to Antarctic ozone depletion on the productivity of the Southern Ocean which surrounds the Antarctic continent. I also supervise the SI solar-radiation monitoring program which has been measuring UV-B radiation in Maryland since the 1970s compiling one of the longest records of spectral irradiance in the world.
Publications
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(2017). Temporal variability in the importance of hydrologic, biotic, and climatic descriptors of dissolved oxygen dynamics in a shallow tidal-marsh creek . Water Resources Research, 53 (8) , 7103-7120. http://dx.doi.org/10.1002/2016WR020196
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(2017). Quantifying phytoplankton productivity and photoinhibition in the Ross Sea Polynya with large eddy simulation of Langmuir circulation . Journal of Geophysical Research: Oceans, 122 (7) , 5545-5565. http://dx.doi.org/10.1002/2017JC012747
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(2017). Watershed influences on the structure and function of riparian wetlands associated with headwater streams – Kenai Peninsula, Alaska . Science of The Total Environment, 599–600 , 124-134. http://dx.doi.org/10.1016/j.scitotenv.2017.03.290
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(2016). Solar Irradiance Changes and Phytoplankton Productivity in Earth's Ocean Following Astrophysical Ionizing Radiation Events. Astrobiology, 16 (4) , 245-258. http://dx.doi.org/10.1089/ast.2015.1360
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(2016). Sentinel responses to droughts, wildfires, and floods: effects of UV radiation on lakes and their ecosystem services. Frontiers in Ecology and the Environment, 14 (2) , 102-109. http://dx.doi.org/10.1002/fee.1228
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(2015). Effect of solar UVR on the production of particulate and dissolved organic carbon from phytoplankton assemblages in the Indian Ocean. Marine Ecology Progress Series, 535 , 47-61. http://dx.doi.org/10.3354/meps11414
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(2015). Long-term variations in primary production in a eutrophic sub-estuary: Contribution of short-term events. Estuarine, Coastal and Shelf Science, 162 , 22-34. http://dx.doi.org/10.1016/j.ecss.2015.01.015
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(2015). Shifts in microbial food web structure and productivity after additions of naturally occurring dissolved organic matter: Results from large-scale lacustrine mesocosms . Limnology and Oceanography, 60 (6) , 2130-2144. http://dx.doi.org/10.1002/lno.10159
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(2015). Solar Irradiance Changes and Photobiological Effects at Earth's Surface Following Astrophysical Ionizing Radiation Events. Astrobiology, 15 (3) , 207-220. http://dx.doi.org/10.1089/ast.2014.1224
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(2014). Kinetics of Photosynthetic Response to Ultraviolet and Photosynthetically Active Radiation in Synechococcus WH8102 (CYANOBACTERIA). Photochemistry and photobiology, 90 (3) , 522-532. http://dx.doi.org/10.1111/php.12202
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(2014). Wavelength and temperature-dependent apparent quantum yields for photochemical formation of hydrogen peroxide in seawater. Environmental Science: Processes & Impacts, 16 (4) http://dx.doi.org/10.1039/c4em00036f
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(2014). Wavelength and temperature-dependent apparent quantum yields for photochemical formation of hydrogen peroxide in seawater. Environmental Science: Processes & Impacts, 16 (4) http://dx.doi.org/10.1039/c4em00036f
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(2014). Effect of CO2, nutrients and light on coastal plankton. II. Metabolic rates. Aquatic Biology, 22 , 43-57. http://dx.doi.org/10.3354/ab00606