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Browse History: Dissolved Oxygen (2013)
Indicator Icon Dissolved Oxygen

Dissolved oxygen is critical to the survival of the Coastal Bay's aquatic life. The amount of dissolved oxygen needed before aquatic organisms are stressed, or even die, varies from species to species.

Maryland Coastal Bays - Indicator Details:





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Threshold Map


This map shows how often dissolved oxygen levels were within designated threshold categories in 2013. Good water quality is characterized by having dissolved oxygen concentrations that are frequently in the higher threshold levels (indicated by shades of green), while poor water quality tends to have dissolved oxygen concentrations that are frequently in the lower threshold categories (indicated by shades of yellow and orange). In 2013, regions of the Coastal Bays generally had moderate to poor levels of dissolved oxygen, with the exception of Chincoteague Bay which was good.

Creating this map
Dissolved oxygen was measured bi-monthly to monthly from June through September at 78 stations in 2013. The minimum dissolved oxygen concentration for each station was scored according to the threshold categories and represented. Scores for each sampling station were then averaged by reporting region and mapped.

Data Map


This map shows minimum bottom dissolved oxygen levels for the summer of 2013. The area with the lowest minimum dissolved oxygen concentration was Newport Bay. Low dissolved oxygen concentrations is regulated primarily by the quantity of water and nutrients.

Understanding this map
Dissolved oxygen was measured bi-monthly to monthly from June through September at 78 stations in 2013. Minimum dissolved oxygen levels are represented at each station.

Ranking


Comparison of Bay Health Index scores for 2013 () compared to
()


Score Legend
 Score (%)
 0               20               40               60               80              100
  
Chincoteague Bay  
St. Martin River  
Overall Coastal Bays  
Assawoman Bay  
Sinepuxent Bay  
Isle of Wight Bay  
Newport Bay  

This figure ranks each region from best to worst for dissolved oxygen. The highest-ranked region in 2013 was Chincoteague Bay, whereas the lowest-ranked region was Newport Bay. 


Excel Spreadsheet

Threshold Levels

ScoreThresholds (mg L-1)
100≥7.0
806.0–<7.0
605.0–<6.0
403.0–<5.0
201.0–<3.0
0 <1.0