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Resolving spatiotemporal characteristics of the seasonal hypoxia cycle in shallow estuarine environments of the Severn River and South River, MD, Chesapeake Bay, USA

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ABSTRACT

The nature of emerging patterns concerning water quality stressors and the evolution of hypoxia within sub-estuaries of the Chesapeake Bay has been an important unresolved question among the Chesapeake Bay community. Elucidation of the nature of hypoxia in the tributaries of the Chesapeake Bay has important ramifications to the successful restoration of the Bay, since much of Bay states population lives within the watersheds of the tributaries. Very little to date, is known about the small sub-estuaries of the Chesapeake Bay due to limited resources and the difficulties in resolving both space and time dimensions on scales that are adequate to resolve this question. We resolve the spatio-temporal domain dilemma by setting up an intense monitoring program of water quality stressors in the Severn and South Rivers, MD. Volume rendered models were constructed to allow for a visual dissection of the water quality times series which illustrates the life cycle of hypoxia and anoxia at the mid to upper portions of the tidal tributaries. The model also shows that unlike their larger Virginian tributary counterparts, there is little to no evidence of severe hypoxic water intrusions from the main-stem of the Chesapeake Bay into these sub-estuaries.

No MeSH data available.


Severn River to mid-Chesapeake Bay transect for dissolved oxygen, 2010.
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fig0065: Severn River to mid-Chesapeake Bay transect for dissolved oxygen, 2010.

Mentions: Severe hypoxia and anoxia develop in both the Severn and South Rivers mainly in the deep middle sections and the very shallow up river sections close to the headwaters, and were not found in either of their estuarine river mouth. The DVR models clearly illustrate that there is no evidence of severe hypoxic or anoxic water masses intruding into these tributaries from the main-stem of the Chesapeake Bay. In contrast, Kou et al. (1991) found that the larger sub-estuarine river systems in the southern portion of the Chesapeake Bay watershed did show evidence of hypoxic waters entering the river mouths, and higher dissolved oxygen concentrations at the headwaters. This was due to the fact these estuarine river systems have deep trenches located at the at their mouths, which allows for the Chesapeake Bay anoxic water to enter [59, 60, 61, 62]. This is opposite to our finding in the smaller tidal tributaries of the northern Chesapeake Bay estuarine river systems. The South and Severn River systems both have shallow sandy sills at the estuarine river mouths and deeper riverine bottoms in the middle of the system. This structure physically prevents the anoxic Chesapeake Bay water from entering the South and Severn River systems. As further evidence for the lack of severe hypoxia entering the Severn River a monitoring transect was performed on August 18, 2010 in the Severn River’s headwaters to the middle of the Chesapeake Bay (Fig. 13). In addition to the DVR models, this transect confirmed that hypoxia was found in the upper and mid sections of the Severn River, well oxygenated water at the Severn River mouth, and hypoxic-anoxic waters in the main stem of the Bay. Further indicating a disconnect between the shallow water estuarine river systems and the main stem of the Chesapeake Bay. This realization is critically important, because it indicates that hypoxia and anoxia develops within the tributary separate from the parent Chesapeake Bay estuary [61].


Resolving spatiotemporal characteristics of the seasonal hypoxia cycle in shallow estuarine environments of the Severn River and South River, MD, Chesapeake Bay, USA
Severn River to mid-Chesapeake Bay transect for dissolved oxygen, 2010.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037264&req=5

fig0065: Severn River to mid-Chesapeake Bay transect for dissolved oxygen, 2010.
Mentions: Severe hypoxia and anoxia develop in both the Severn and South Rivers mainly in the deep middle sections and the very shallow up river sections close to the headwaters, and were not found in either of their estuarine river mouth. The DVR models clearly illustrate that there is no evidence of severe hypoxic or anoxic water masses intruding into these tributaries from the main-stem of the Chesapeake Bay. In contrast, Kou et al. (1991) found that the larger sub-estuarine river systems in the southern portion of the Chesapeake Bay watershed did show evidence of hypoxic waters entering the river mouths, and higher dissolved oxygen concentrations at the headwaters. This was due to the fact these estuarine river systems have deep trenches located at the at their mouths, which allows for the Chesapeake Bay anoxic water to enter [59, 60, 61, 62]. This is opposite to our finding in the smaller tidal tributaries of the northern Chesapeake Bay estuarine river systems. The South and Severn River systems both have shallow sandy sills at the estuarine river mouths and deeper riverine bottoms in the middle of the system. This structure physically prevents the anoxic Chesapeake Bay water from entering the South and Severn River systems. As further evidence for the lack of severe hypoxia entering the Severn River a monitoring transect was performed on August 18, 2010 in the Severn River’s headwaters to the middle of the Chesapeake Bay (Fig. 13). In addition to the DVR models, this transect confirmed that hypoxia was found in the upper and mid sections of the Severn River, well oxygenated water at the Severn River mouth, and hypoxic-anoxic waters in the main stem of the Bay. Further indicating a disconnect between the shallow water estuarine river systems and the main stem of the Chesapeake Bay. This realization is critically important, because it indicates that hypoxia and anoxia develops within the tributary separate from the parent Chesapeake Bay estuary [61].

View Article: PubMed Central - PubMed

ABSTRACT

The nature of emerging patterns concerning water quality stressors and the evolution of hypoxia within sub-estuaries of the Chesapeake Bay has been an important unresolved question among the Chesapeake Bay community. Elucidation of the nature of hypoxia in the tributaries of the Chesapeake Bay has important ramifications to the successful restoration of the Bay, since much of Bay states population lives within the watersheds of the tributaries. Very little to date, is known about the small sub-estuaries of the Chesapeake Bay due to limited resources and the difficulties in resolving both space and time dimensions on scales that are adequate to resolve this question. We resolve the spatio-temporal domain dilemma by setting up an intense monitoring program of water quality stressors in the Severn and South Rivers, MD. Volume rendered models were constructed to allow for a visual dissection of the water quality times series which illustrates the life cycle of hypoxia and anoxia at the mid to upper portions of the tidal tributaries. The model also shows that unlike their larger Virginian tributary counterparts, there is little to no evidence of severe hypoxic water intrusions from the main-stem of the Chesapeake Bay into these sub-estuaries.

No MeSH data available.