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Student Spotlight

Deb Goodwin


Alumna Profile: Deborah Goodwin

Degree: Earth and Evironmental Science: Oceanography

 

Dissertation Title: Satellite-Derived Fluorescence Quantum Yields as Indicators of Phytoplankton Photophysiology

Advisor: Dr. Ru Morrison

 


Description of Research

Presently, regional and global satellite-based models of ocean primary productivity and carbon cycling are driven by remote sensing-derived estimates of chlorophyll concentration and/or phytoplankton carbon biomass. Increased understanding of algal physiological responses to photosynthesis forcing factors (including light, nutrient status and water column structure) will help decrease uncertainties in future ocean primary production estimates. MODIS/Aqua measurements of fluorescence line height (FLH), a measure of the sun-induced chlorophyll fluorescence, provide an important window into the phytoplankton photosynthetic apparatus and physiological variability on a global scale. In open ocean waters, FLH values are not significantly influenced by suspended material or CDOM. Recent research has demonstrated the effects of both nutrient stress and photoacclimation on fluorescence efficiency. Photoacclimation reflects physiological responses aimed at minimizing the influence of changes in growth irradiance, thus merging incident irradiance levels, in-water light attenuation and vertical mixing dynamics. A climatological analysis of fluorescence quantum yields in coastal Gulf of Maine waters found that up to 92% of the annual variability was associated with growth irradiance, with little evidence of nutrient effects.

My research explores seasonal patterns in phytoplankton photophysiological responses to varying growth irradiances across a range of locations and ecological regimes in the North Atlantic. MODIS/Aqua-derived fluorescence quantum yields, instantaneous photosynthetically available radiation and mixed layer depth data are integrated in a number of different analyses. Photoinhibition during times of highest growth irradiances is suggested at many sites, and spatial variability in seasonal patterns may be associated with local hydrodynamic regimes.

I also assist with maintenance and data validation efforts for the Great Bay Coastal Buoy. This monitoring platform contains instruments that measure a suite of water quality and meteorological parameters every half hour. Data is sent to a base station by telemetry and then made available to scientists, policy makers, educators and other users in numerical and graphical forms. Comparison against a multi-year historical dataset helps us assess the rate and intensity of observed physical, chemical and biological changes in the Great Bay estuarine ecosystem.

Finally, I work with the NSF-funded Center for Ocean Sciences Education Excellence – Ocean Systems (COSEE-OS) to advance collaborations between scientists and formal/informal educators through workshops, semester-long courses and online multimedia tools. Through this partnership, I have been part of a new effort by the UNH Earth Science and Education Departments to reach the next generation of marine scientists and teachers. I will be developing and co-teaching an innovative course during the 2009-2010 academic year, entitled “Exploring Informal Science Education Through Ocean Inquiry.”

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