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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(2007). Photobleaching of dissolved organic material from a tidal marsh-estuarine system of the Chesapeake Bay . Photochemistry and photobiology, 83 (4) , 782-792. http://dx.doi.org/10.1111/j.1751-1097.2007.00142.x
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(2006). Sublethal exposure to UV radiation affects respiration rates of the freshwater cladoceran Daphnia catawba . Photochemistry and photobiology, 82 , 547-550.
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(2006). Bio-optics of the Chesapeake Bay from measurements and radiative transfer closure. Estuarine, Coastal and Shelf Science, 68 , 348-362.
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(2005). UV effects on photosynthesis, growth and acclimation of an estuarine diatom and cryptomonad . Marine Ecology Progress Series, 300 , 53-62.
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(2005). Smithsonian-NIST-USDA-FPL Network for Monitoring Solar Ultraviolet Irradiance:: comparison of radiometer measurements and radiative transfer model calculations. Service Life Prediction: Challenging the Status Quo. Proceedings of the 3rd International Symposium on Service Life Prediction (159-170) Federation of Societies for Coatings Technology .
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(2005). Photochemical production of hydrogen peroxide and methylhydroperoxide in coastal waters . Marine Chemistry, 97 , 14-33.
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(2004). UVA variability overrules UVB ozone hole depletion on the photoreduction of iron in the Souther Ocean . Geophysical Research Letters, 31 , L24310, doi.
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(2003). Phytoplankton productivity by Williams, Thomas and Reynolds. Newsletter, International Association of Theoretical and Applied Limnology, 38 , 8.
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(2003). Modulation of UV exposure and effects by vertical mixing and advection. UV effects in aquatic organisms and ecosystems (107-134) Royal Society of Chemistry .
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(2002). Effects of UV-B radiation on terrestrial and aquatic primary producers. Annual Review of Ecology and Systematics, 33 , 371-396.
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(2002). Partitioning spectral absorption in case 2 waters: discrimination of dissolved and particulate components . Applied Optics. Information Processing, 41 , 4220-4233.
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(2002). A two-year time series of continuously monitored inherent optical properties in a eutrophic sub-estuary of Chesapeake Bay . Ocean Optics XVI (8) Office of Naval Research .
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(2002). Increased sensitivity to ultraviolet radiation in nitrogen-limited dinoflagellates: photoprotection and repair . Limnology and Oceanography, 47 , 86-94.
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(2002). Experimental exposure of plankton suspensions to polychromatic ultraviolet radiation for determination of spectral weighting functions. Ultraviolet ground-and- space-based measurements, models, and effects: 30 July- August 2001, San Diego, USA / James R. Slusser, et al, Editors (291-296) Society of Photo-optical Instrumentation Engineers (SPIE) .