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Estimating reference nutrient criteria for Maryland ecoregions
Raymond P Morgan1, Kathleen M Kline, John B Churchill
1University of Maryland Center for Environmental Science, Appalachian Laboratory, 301 Braddock Road, Frostburg, MD 21532-2307, USA. rmorgan@umces.edu
Environmental Monitoring and Assessment
|May 31, 2012
Summary
Protecting water quality requires managing stream nutrients. This study reveals elevated total nitrogen (TN) and total phosphorus (TP) in Maryland
Area of Science:
- Environmental Science
- Ecology
- Water Quality Management
Background:
- Stream nutrient management is critical for safeguarding water quality and aquatic ecosystems across the USA.
- Small-order, non-tidal streams are vital components of larger watershed systems, influencing downstream water quality.
- Understanding nutrient dynamics in these headwater streams is essential for effective environmental protection strategies.
Purpose of the Study:
- To analyze the relationships between landscape characteristics and nutrient concentrations (total nitrogen and total phosphorus) in small-order, non-tidal streams within Maryland's ecoregions.
- To establish preliminary reference nutrient estimates for different ecoregions to aid in assessing stream health.
- To identify ecoregions and stream orders with particularly high nutrient levels and assess their potential impact on the Chesapeake Bay.
Main Methods:
- Utilized an extensive water quality database from the Maryland Biological Stream Survey (MBSS).
- Analyzed nutrient concentrations (TN and TP) in relation to landscape characteristics across USEPA L2 and L3 ecoregions.
- Calculated nutrient estimates using percentiles (25th and 75th) for reference conditions within six Maryland ecoregions.
Main Results:
- Significant variations in TN and TP concentrations were observed across Maryland's ecoregions and stream orders.
- The Northern Piedmont and Middle Atlantic Coastal Plain ecoregions exhibited particularly elevated nutrient levels.
- First-order streams showed nutrient loading equivalent to second- and third-order streams, highlighting the importance of headwater nutrient control.
Conclusions:
- Increased efforts are needed to prevent nutrient inputs into first-order streams to protect overall stream ecosystem integrity.
- Elevated nutrient levels in small-order streams pose a potential risk to the Chesapeake Bay's estuarine ecosystems.
- The established reference nutrient estimates provide valuable benchmarks for water quality assessment and management in Maryland streams.
