Life Sciences Commons^™

Nitrate Reductase Activity, Nitrate Uptake And Iodine Speciation In The Marine Environment, Chin-Chang Hung

OES Theses and Dissertations

The present method for the determination of new production (NP) by measuring the uptake of added ¹⁵NO₃^– suffers from a number of limitations. In an attempt to improve this situation, this research examined the possibility of estimating ¹⁵NO₃– uptake by measuring the activity of nitrate reductase (NRA). In addition, because it has long been suspected that the biological reduction of IO₃^– to I^– may be mediated by nitrate reductase (NR), this research investigated the ability of NR to catalyze the reduction of iodate to iodide.

An improved method for the determination …

Encystment, Excystment And Photosynthetic Activity In The Temporary Cysts Of Amphidinium Carterae, Steven R. Kibler

OES Theses and Dissertations

Although the formation of temporary cysts has been documented in several papers, the physiology of these stages has remained obscure. Research dealing with dinoflagellate resting stages has primarily targeted sexual cysts. Accordingly, formation, germination and photosynthetic activity in the temporary cysts of Amphidinium carterae have been investigated in the present study. The effect of light intensity upon cyst germination was tested by incubating temporary cysts at three different light intensities. In order to assess the potential for photosynthesis in cysts, cellular chlorophyll-a concentrations and cellular fluorescence were quantified during encystment. Photosynthetic carbon uptake of H¹⁴CO₃^- was …

The Impacts Of External Nutrient Sources On Marine Phytoplankton In An Eastern Shore Sea-Side Estuary, Claudette Lajoie Jenkins

OES Theses and Dissertations

The Eastern Shore of Virginia (Greens Creek) as well as a large portion of the North Atlantic coastline is characterized by estuarine systems not dominated by large river systems. Instead, small freshwater creeks influence many coastal systems yet little information has been documented on their ecological significance. The focus of this research is to identify the biogeochemical and physical interactions within an estuarine water-column and understand the importance of freshwater sources in governing phytoplankton production. The hypothesis of this research is that increases in external nutrient loading into Greens Creek will not result in an increase in primary production. The …