Assessment of chlorophyll-a as a criterion for establishing nutrient standards in the streams and rivers of Illinois

Royer, TV; David, MB; Gentry, LE; Mitchell, CA; Starks, KM; Heatherly, T; Whiles, MR

HERO ID

3608539

Reference Type

Journal Article

Year

2008

Language

English

PMID

18268307

HERO ID 3608539
In Press No
Year 2008
Title Assessment of chlorophyll-a as a criterion for establishing nutrient standards in the streams and rivers of Illinois
Authors Royer, TV; David, MB; Gentry, LE; Mitchell, CA; Starks, KM; Heatherly, T; Whiles, MR
Journal Journal of Environmental Quality
Volume 37
Issue 2
Page Numbers 437-447
Abstract Nutrient enrichment is a frequently cited cause for biotic impairment of streams and rivers in the USA. Efforts are underway to develop nutrient standards in many states, but defensible nutrient standards require an empirical relationship between nitrogen (N) or phosphorus (P) concentrations and some criterion that relates nutrient levels to the attainment of designated uses. Algal biomass, measured as chlorophyll-a (chl-a), is a commonly proposed criterion, yet nutrient-chl-a relationships have not been well documented in Illinois at a state-wide scale. We used state-wide surveys of >100 stream and river sites to assess the applicability of chl-a as a criterion for establishing nutrient standards for Illinois. Among all sites, the median total P and total N concentrations were 0.185 and 5.6 mg L(-1), respectively, during high-discharge conditions. During low-discharge conditions, median total P concentration was 0.168 mg L(-1), with 25% of sites having a total P of > or =0.326 mg L(-1). Across the state, 90% of the sites had sestonic chl-a values of < or =35 microg L(-1), and watershed area was the best predictor of sestonic chl-a. During low discharge there was a significant correlation between sestonic chl-a and total P for those sites that had canopy cover < or =25% and total P of < or =0.2 mg L(-1). Results suggest sestonic chl-a may be an appropriate criterion for the larger rivers in Illinois but is inappropriate for small rivers and streams. Coarse substrate to support benthic chl-a occurred in <50% of the sites we examined; a study using artificial substrates did not reveal a relationship between chl-a accrual and N or P concentrations. For many streams and rivers in Illinois, nutrients may not be the limiting factor for algal biomass due to the generally high nutrient concentrations and the effects of other factors, such as substrate conditions and turbidity.
Doi 10.2134/jeq2007.0344
Pmid 18268307
Wosid WOS:000253929600018
Url http://search.proquest.com/docview/14843588?accountid=171501
Is Certified Translation No
Dupe Override No
Is Public Yes
Language Text English
Keyword Illinois; Creeks & streams; Water quality; Site selection; Quality standards; Drinking water; Clean Water Act-US
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