Sediment oxygen demand and biochemical oxygen demand : patterns of oxygen depletion in tidal creek sites
- UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
- Tara A. Macpherson (Creator)
- Institution
- The University of North Carolina Wilmington (UNCW )
- Web Site: http://library.uncw.edu/
- Advisor
- Daniel Baden
Abstract: Concerns about low dissolved oxygen levels in New Hanover County, North
Carolina tidal creeks resulted in a study measuring rates of oxygen loss as water-column
biochemical oxygen demand (BOD5) and sediment oxygen demand (SOD). Selected
tidal creek sites were sampled monthly from July 2001 to August 2002 in collaboration
with the New Hanover County Tidal Creeks monitoring project to identify any trends that
may be evident concerning rates of oxygen loss. BOD5 rates ranged from 0.0 to 7.6
mg l-1 and were strongly correlated with chlorophyll a measurements. This indicates that
conditions leading to algal blooms have the potential to cause increased BOD and thus
contribute to hypoxia in tidal creeks. SOD rates ranged from –1.5 to 6.3 g O2 m-2 d-1.
Both rates of oxygen uptake were seasonally dependent. Oxygen loss to sediments was
greater and more variable than oxygen loss in the water column, indicating that SOD
should be considered in all comprehensive water quality monitoring programs. Results
indicate that sediment composition and the bioavailability of organic matter may be key
elements in determining SOD. On-land processes that increase sedimentation of organic
material may contribute to creek hypoxia incidents. Groundwater inputs decreased SOD
rates at selected sites, thus recharge areas may be critical to tidal creek health.
Correlation and principal component analyses were conducted using SAS statistical
software to assess the effects of numerous variables on oxygen demand. The results
suggest that BOD5 responds to a suite of environmental variables including temperature,
salinity, chlorophyll a, total and organic suspended solids and rainfall while SOD
responds to salinity and nutrients.
Sediment oxygen demand and biochemical oxygen demand : patterns of oxygen depletion in tidal creek sites
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Created on 1/1/2009
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Additional Information
- Publication
- Thesis
- A Thesis Submitted to the University of North Carolina Wilmington in Partial Fulfillment of the Requirements for the Degree of Master of Science
- Language: English
- Date: 2009
- Keywords
- Oxygen--Measurement, Rivers--North Carolina--New Hanover County
- Subjects
- Oxygen -- Measurement
- Rivers -- North Carolina -- New Hanover County