A eutrophication assessment of two south Texas estuaries




Hayes, Kenneth

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Texas’s coast is one of the fastest growing regions in the United States, prompting a concern that the coastal development will lead to eutrophication. High nutrient levels associated with eutrophication have been associated with increased chlorophyll and phytoplankton concentrations, including nuisance and toxic algae, and hypoxic conditions. The U.S. EPA has encouraged states to adopt numerical nutrient criteria as a method to decrease nutrient pollution, but Texas is without numerical nutrient water quality standards. A needed first step towards development of these standards is to assess and prioritize coastal ecosystems in the region of interest (in this case, the Texas coast). This study focused on applying three different eutrophication assessment approaches (EPA, NOAA, and TCEQ) to determine if Oso and Baffin bays are experiencing degraded or impaired water quality due to excessive nutrient loading. Results from the study indicate that regardless of the classification approach used, Oso Bay is experiencing degraded water quality and its water quality would be considered “poor” and eutrophic. For Baffin Bay, the results from the study using both the EPA and NOAA classification approaches indicate that Baffin Bay is experiencing degraded water quality and its water quality would be considered “poor” and eutrophic. However, if using TCEQ as a classification approach Baffin Bays water quality would be “good”. This discrepancy was due to all their criteria not having consistent indicators or cutpoint concentrations. These findings demonstrate the need for uniform numerical water quality standards and indicators.



eutrophication, Harmful Algae, nutrients, Water Quality Standards



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