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Date Permissions Signed
Date of Award
Master of Science (MS)
Sulkin, Stephen D.
Van Alstyne, Kathryn Lyn, 1962-
Donovan, Deborah Anne, 1964-
Current global conditions are leading to increased numbers of harmful macroalgal blooms, which have detrimental effects on the ecosystems in which they occur. Macroalgae produce harmful chemicals such as ROS (reactive oxygen species) and dopamine. These chemicals may be produced in high quantities in response to environmental stresses, such as increasing water temperature, emersion, hypoxia, and then subsequently introduced into the aquatic environment. In Washington State, little work has been done to quantify ROS accumulation by macroalgae, or investigate oxidant impacts on invertebrates. This project investigated the impacts of environmental (emersion, water temperature, hypoxia) and chemical (dopamine) stressors on oxidant accumulation in two bloom forming macroalgae (Ulvaria obscura and Ulva lactuca) in Washington State. The effects of hydrogen peroxide (H2O2) on Metacarcinus magister zoeae survival and development were also investigated. Oxidant concentrations changed in U. obscura after exposure to emersion stress. Seawater with previously emersed algae accumulated oxidants at a rate that was one order of magnitude less than seawater with algae that remained submerged. Water temperature and environmental dopamine significantly changed oxidant concentrations in U. lactuca, but not U. obscura. Seawater with U. lactuca that were exposed to 10o C seawater accumulated more oxidants than algae exposed to 15o C and 20o C seawater. Stage I Metacarcinus magister zoeae were exposed to hydrogen peroxide levels ranging from no hydrogen peroxide to 6 μM. All zoeae had similar mortality rates; those exposed to hydrogen peroxide had slightly, but not significantly higher mortalities. Zoeae in all treatments also had similar stage durations of 11.6 days. These results suggest that zoeal survival and development rate are unaffected by accumulated oxidants in the concentrations and exposure times used in this experiment.
Western Washington University
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van Hees, David H., "The effects of environmental stressors on oxidant accumulation by ulvoid algae and the impacts of hydrogen peroxide on larval Metacarcinus magister survival and development" (2011). WWU Graduate School Collection. 171.