Spatial and temporal trends of algal biomass in small and large streams in Indiana, 200105

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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
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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

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WHAT IS NUTRIENT ENRICHMENT?

• USEPA Nutrient Criteria 25th Percentile
  (Nutrient Ecoregions VI, VII, IX)
• Total Nitrogen 0.54 2.18 mg/L
• Total Phosphorus 0.033 0.076 mg/L
• Chlorophyll a seston 1.54 2.7 mg/L
• Chlorophyll a periphyton 20.4 mg/m2
• IDEM/USGS 25th Percentile
• Chlorophyll a periphyton 6.9 28.4 mg/m2

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ALGAL BIOMASS VARIABLES

• Chlorophyll a - total amount of autotrophic
  organisms in the sample
• Algal types
• Seston free floating algae
• Periphyton attached algae

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Chlorophyll aTotal Nitrogen Criteria
Periphyton
Seston
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Total NitrogenChlorophyll a Criteria
Periphyton
Seston
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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?

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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)

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ALGAL BIOMASS SAMPLING SITES 2001 - 2005
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FACTORS AFFECTING CHLOROPHYLL a

• Seasonal Patterns
• Hydrology
• Stream size
• Spatial Differences

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CHLOROPHYLL CONCENTRATIONS
Sugar Creek 2004
Seasonal Factors
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CHLOROPHYLL CONCENTRATIONS
Big Walnut Creek
USEPA 25th percentile
Hydrologic Factors
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CHLOROPHYLL CONCENTRATIONS
Periphyton
Seston
Stream Size Factors
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CHLOROPHYLL CONCENTRATIONS
Tributaries
Spatial Factors
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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

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THE END

• Jeff Frey
• jwfrey_at_usgs.gov
• http//in.water.usgs.gov/NAWQAWHMI/

Bledsoe Branch 2001