Numerical Study of the Physical Conditions that Lead to Hypoxia Events in Long Bay, SC
Dr. George Voulgaris1, Dr. Rosario Sanay1, Dr. Robert Hetland2
1Department of Geological Sciences, University of South Carolina
2Texas A&M University
The following research effort proposed by Voulgaris et al. builds upon the work conducted as part of the SECOORA-funded Long Bay coastal hypoxia study. The results from this study will be used to guide the numerical experiments proposed by Voulgaris et al. in their ongoing research regarding coastal hypoxia in Long Bay, SC.
Based on the physical conditions of the coastal ocean during the 2004 hypoxia event, as well as information from the literature, the processes that may play an important role in triggering or exacerbating a hypoxia event in Long Bay can be summarized as:
- Oceanographic/atmospheric processes that enhance water column stratification are river input, heating, and the intrusion of cold water from the Gulf Stream associated with upwelling-favorable wind conditions;
- Oceanic sources of nutrient-rich water caused by Gulf Stream intrusions; and
- Anthropogenic sources of organic material and nutrients: organic-rich matter entering the Bay from the rivers, estuaries, swashes, as well as storm water runoff from the highly urbanized Grand Strand area.
In consideration of these factors, this study will address a number of questions through the development of “process-oriented numerical simulations”:
- How does inner shelf water column stratification (timing and degree) affect cold water intrusion during upwelling favorable conditions?
- What is the role and relative importance of buoyancy, wind, and heat flux forcing on the shoreward cold water intrusion?
- When does a cold water intrusion event lead to hypoxia?
- What is the relative contribution of anthropogenic versus oceanic (e.g. nutrient-rich Gulf Stream cold water) nutrient sources to hypoxia event occurrence in Long Bay?
- Could hypoxia events become a recurrent issue in Long Bay?
The long-term goal is to develop a robust nowcast/forecast nearshore circulation model that can be used to anticipate possible hypoxia events in Long Bay, SC. The overall objective is to identify the physical scenarios under which hypoxia events in Long Bay may occur, and to provide insights into threshold conditions to predict the occurrence of these events that can be used by coastal managers.