Chapter 32 Effects of Nutrient Enrichment on Periphyton

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Chapter 32 Effects of Nutrient Enrichment on
Periphyton

• Christopher Eisler
• Tennessee Tech University

in.water.usgs.gov
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Periphyton

• Periphyton are defined as micro floral growth
  upon substrata.
• Factors Influencing Periphyton Growth.
• 1. Light
• 2. Temperature
• 3. Water Velocity
• 4. Grazing Pressure
• 5. Nutrient and Toxic Loading

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Local Assessment

• Testing is a must to determine nutrient affects
  in the stream of concern.
• More Control Less Applicable
• Less Control Greater Applicability for current
  conditions
• Time and Space change the stream

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Local Assessment

• Factors controlling natural periphyton growth are
  less well understood than other phenomenon.
• Low nutrient levels in streams can still meet
  growth needs due to water flow.

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Temporal Nutrient Additions

• Nutrient additions may occur as a
• pulse
• Pulse Occurrences
• Times of Day
• Storms
• Seasonal (Fall can be a time of high nutrient
  addition)

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Methods

• Method Selection Depends On Spatial Scale
• Advantages and Disadvantages for each
• Four Types of Methods
• Point Source- best in 3 to 4 order streams
• Flow Through Enclosures- best in 3 to 4 order
  streams
• Whole Stream Manipulations- best in 1 to 2 order
• Integrated Approaches

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Point Source

• Allows stream testing without enclosure
• Low Control but in natural settings
• Nutrient Diffusing Substrata has low impact
• Nutrient solution is sealed inside a terracotta
  pot with a solid bottom
• Simulation of Natural Phenomenon
  (ex.Chironimidae)

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Point Source

• Advantages
• 1. Effective in nutrient cycling evaluations
• 2. Validation of Models
• 3. Detecting limits in Shotgun approach
• 4. Supplements other techniques

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Point Source

• Disadvantages
• 1. Inconsistencies in release (Pulse Phenomenon)
• Algae Example
• 2. Terracotta Problems
• Fe, Ca, Al lock up P
• Inconsistencies in materials
• A slow release fertilizer can help overcome some
  problems.

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Point Source- Matlock Periphyton Meter

• Uses Glass Wool and a Bio filter over a plastic
  bottle
• Slowly Releases Nutrients
• Overcomes many problems

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Flow Through Enclosures

• Also called Flumes
• Serve as a way to modify such variables as flow,
  nutrient content, substrate size.
• Can rise and fall with the stream
• Must be open on top however to avoid enclosure
  effects

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Whole Stream Assessment

• Realistic but time consuming since not just
  periphyton affected
• Low Flows Best
• Alternative to radio isotopes is addition of low
  amount of nutrient.

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Integrative Approach

• Allow comparison through differing scales
• Can show interactions between substrate and water
  column
• Synergistic effects can be measured in this and
  other methods
• No3 and PO4 Limitation Example
• Sometimes temperature can affect flow rate in a
  method

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Algal Assessment

• Effects measured by Chlorophyll a and Free Dry
  Mass (AFDM)
• A method should be determined by the scale to be
  measured
• Accessibility of sites should be considered since
  nutrients may need refilling

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Method Selection

• A method should be determined by the scale to be
  measured
• Consider accessibility of sites, nutrients may
  need refilling

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Questions
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Chapter Questions

• 1. It may lock up nutrients for example Fe, Ca,
  Al lock down P. Phosphorous may not defuse while
  other nutrients do if P limits growth. Conversely
  it may defuse to much to soon. If this occurs
  algal sloughing may occur giving a false reading.
  
• 3. A limiting nutrient may not be there in the
  right a mount for growth to occur. Another reason
  is algae may have sloughed off already.

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Chapter Questions

• 5. Caution is needed since the method for one
  scale may be biased when applied to another
  scale. Also a stream can have many tributaries
  that may cause dilution.
• 7. Grazers could affect results at site since bio
  mass could be easily available. The second part
  is not answerable. To quantify effects of
  grazers raise the saucers off the bottom.

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Environmental Assessment NoteChapter 34

• Knowledge of nutrient effects on algae can be
  used assess ecosystem quality
• Algae have been used for a very long time to
  monitor water quality (Especially Europe)
• Relatively inexpensive and easy to catch them

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Environmental Assessment NoteChapter 34

• Resources Rapid Bioassessment Protocols for Use
  in Streams and Wadeable Rivers Periphyton,
  Benthic Macroinvertebrates, and Fish Second
  Edition
• http//www.epa.gov/owow/monitoring/rbp/
• Technical Guidance Manual Rivers Streams
• http//www.epa.gov/waterscience/criteria/nutrient/
  guidance/rivers/index.html
• Other resources listed in
• Haur, F. R., and G.A. Lamberti, 2006 Methods in
  Stream Ecology 2nd edition. New York, New York
  Academic Press.