Virginia Institute of Marine Science
Athens Institute for Education and Research. ATINER'S Conference Paper Series, No: ENV2013-0425
Statistics are applied to analyze the correlations of summer hypoxia in the Chesapeake Bay with watershed input and wind conditions based on nearly three decades of monitoring data. The Pearson correlation coefficients indicate that the averaged summer hypoxia has strong positive correlation with watershed nutrient load and discharge, and moderate negative correlation with summer average wind speed. Nutrient inputs and the subsequent decay of organic matter are the primary factor that controls the oxygen demand causing summer hypoxia, while episodic wind can partly erode stratification and hypoxia. The interannual variation of hypoxia is mainly controlled by watershed input, but wind plays an important role in modulating hypoxia, such as variations of hypoxic volumes in individual summer months. Although the extent of hypoxia reduction is different with different wind directions, a faster wind speed (above certain strength) causes stronger destratification and hypoxia reduction than weaker speeds, which is generally more important than the effect due to wind directions. Computer modelling is used to obtain dissolved oxygen conditions in finer temporal and spatial scales to supplement the discrete observations in scattered monitoring stations to better understand hypoxia development under episodic wind events, which enhances the understanding on physical relationships among the concerned constituents beyond the statistical analysis.
Hypoxia, nutrient load, freshwater discharge, wind speed and directions, destratification, correlation analysis
Wang, P., Wang, H., & Linker, L. (2013) Assessment of Hypoxia and its Relationship with Nutrient Loads and Wind, and Implication to the Chesapeake Bay Management. Athens Institute for Education and Research. ATINER'S Conference Paper Series, No: ENV2013-0425. Virginia Institute of Marine Science, College of William and Mary. https://scholarworks.wm.edu/reports/2012