Tuesday, May 19, 2009
Ambassador Ballroom
The U.S. Geological Survey is leading a nutrient criteria study of 46
streams in Pennsylvania, Maryland, Virginia and West Virginia. Sampling
took place during the summers of 2004 and 2005 and a subset of these data
was used for this study to test the hypothesis that the direct in-stream
response of primary productivity can be predicted by phosphorus and
nitrogen supply rates and light levels. The best results of a bivariate
linear regression analysis of the 2 years of data found gross primary
productivity to have a strong correlation with the supply rate of total
nitrogen (r2=0.42), total phosphorus (r2=0.74) and light (r2=0.51). A
multivariate stepwise regression analysis with the same parameters yielded
a stronger correlation (r2=0.88). This study suggests that for shallow
flowing waters, primary productivity shows a better correlation with
nutrient supply rates instead of nutrient concentrations that doesn't take
into account the effects of stream discharge and channel surface area.
streams in Pennsylvania, Maryland, Virginia and West Virginia. Sampling
took place during the summers of 2004 and 2005 and a subset of these data
was used for this study to test the hypothesis that the direct in-stream
response of primary productivity can be predicted by phosphorus and
nitrogen supply rates and light levels. The best results of a bivariate
linear regression analysis of the 2 years of data found gross primary
productivity to have a strong correlation with the supply rate of total
nitrogen (r2=0.42), total phosphorus (r2=0.74) and light (r2=0.51). A
multivariate stepwise regression analysis with the same parameters yielded
a stronger correlation (r2=0.88). This study suggests that for shallow
flowing waters, primary productivity shows a better correlation with
nutrient supply rates instead of nutrient concentrations that doesn't take
into account the effects of stream discharge and channel surface area.
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