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Browse History: Total Nitrogen (2013)
Indicator Icon Total Nitrogen

Total nitrogen is a measure of several nitrogen constituents, such as nitrate, nitrite, ammonium and organic nitrogen. The concentration of this indicator is a measure of a range of nitrogen conditions that either support (lower concentrations) or degrade (higher concentrations) a healthy ecosystem.

Maryland Coastal Bays - Indicator Details:





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Threshold Map


This map illustrates the overall total nitrogen (TN) scores for each of the six reporting regions. In 2013, Assawoman, Isle of Wight, Sinepuxent, and Chincoteague Bays had good to excellent TN scores, indicating that this nutrient was low enough in concentration to not negatively affect water quality conditions in these reporting regions. TN concentrations were moderate in Newport Bay and poor in St. Martin River.

Creating this map
Total nitrogen (TN) samples were collected at 78 stations, bimonthly to monthly over the entire year. Data from each sampling station was used to calculate a median concentration and an attainment score was subsequently derived using multiple health-based thresholds. TN scores for each sampling station were then averaged by reporting region and mapped.

Data Map


This map shows the total nitrogen (TN) concentrations for all stations in 2013. In 2013, TN concentrations were good to excellent in Assawoman, Isle of Wight, Sinepuxent, and Chincoteague Bays, indicating that this nutrient was low enough to not negatively affect water quality conditions in these reporting regions. TN concentrations were moderate in Newport Bay and poor in St. Martin River.

Understanding this map
The percentage that the median total nitrogen concentration for each sampling station within a reporting region occurred in the various threshold categories during the year was determined.

Ranking


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


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

This figure ranks each region from best to worst for total nitrogen. Sinepuxent Bay had the best TN score, followed by Chincoteague Bay, Isle of Wight Bay, and Assawoman Bay in descending order. Regions with the poorest TN scores were St. Martin River and Newport Bay.


Excel Spreadsheet

Threshold Levels

ScoreThresholds (mg L-1)
100<0.55 td="">
800.55–<0.65
600.65–<1.0
401.0–<1.5
201.5–<2.0
0≥2.0