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Explore the study on algal biomass trends in small and large streams in Indiana from 2001-2005, factors affecting chlorophyll concentrations, and implications for nutrient enrichment. The research aims to develop Indiana-specific Nutrient Criteria based on algal data.
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Spatial and temporal trends of algal biomass in small and large streams in Indiana, 2001-05 Jeffrey W. Frey, Brian J. Caskey, Donald R. Leer,Timothy R. Lathrop,and B. Scott Lowe U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey
OUTLINE OF TALK • What is Nutrient Enrichment? • USEPA Nutrient Criteria • Relation between chlorophyll a and nutrients • IDEM/USGS algal biomass study • Factors affecting chlorophyll a concentrations • Conclusions
WHAT IS NUTRIENT ENRICHMENT? USEPA Nutrient Criteria 25th Percentile (Nutrient Ecoregions VI, VII, IX) • Total Nitrogen0.54 – 2.18 mg/L • Total Phosphorus0.033 – 0.076 mg/L • Chlorophyll aseston1.54 – 2.7mg/L • Chlorophyll aperiphyton20.4 mg/m2 IDEM/USGS 25th Percentile • Chlorophyll aperiphyton6.9 – 28.4 mg/m2
ALGAL BIOMASS VARIABLES • Chlorophyll a - total amount of autotrophic organisms in the sample • Algal types Seston – free floating algae Periphyton – attached algae
Chlorophyll a:Total Nitrogen Criteria Periphyton Seston
Total Nitrogen:Chlorophyll a Criteria Periphyton Seston
IDEM/USGS ALGAL BIOMASS STUDY: Objectives • Fill in missing chlorophyll a data • Collect data to develop Indiana specific Nutrient Criteria • Do biological communities show impacts of nutrient enrichment?
IDEM/USGS ALGAL BIOMASS STUDY: Approach • Sites were randomly selected within each basin • Stream flow rarely monitored • 34-38 sites were sampled 3 times for chlorophyll (May, July, September) • 2-3 NAWQA trend sites 7-10 times per year (May-October)
FACTORS AFFECTING CHLOROPHYLL a • Seasonal Patterns • Hydrology • Stream size • Spatial Differences
CHLOROPHYLL CONCENTRATIONS Sugar Creek 2004 Seasonal Factors
CHLOROPHYLL CONCENTRATIONS Big Walnut Creek USEPA 25th percentile Hydrologic Factors
CHLOROPHYLL CONCENTRATIONS Seston Periphyton Stream Size Factors
CHLOROPHYLL CONCENTRATIONS Seston Periphyton Tributaries Spatial Factors
IDEM/USGS ALGAL BIOMASS STUDY: Conclusions • Few relations between nutrients and chlorophyll a • Many factors affect chlorophyll a concentrations • Biological community data are needed to determine if streams are nutrient enriched
THE END Jeff Frey jwfrey@usgs.gov http://in.water.usgs.gov/NAWQAWHMI/ Bledsoe Branch 2001