Sediment Depth Accumulation and Benthic Macroinvertebrates

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Sediment Depth Accumulation and Benthic
Macroinvertebrates

• Tom Chance, John McConnaughey, John Sorensen,
  Caselle Wood

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Mr. Ingles Pond

• Located south of Kendrick, ID (agricultural area)
• Built in 1996
• 2-3 acres surface area
• Depth of 14-16 feet
• Initial and supplemental stocking of fish
• Fishing has declined

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Objectives

• Analyze sediment depth accumulation
• water content of sediment
• organic matter content
• Analyze deepwater macroinvertebrates
• Identify species composition
• Estimate the density

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Sediment Accumulation

• System capacity
• Nutrient cycling potential
• Fish spawning
• Fish foraging
• Affect on primary production

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Benthic Macroinvertebrates

• Food Chain Value
• Food for fish (adult and larval invertebrates)
• Recycling of organic matter
• Upon death, leave behind nutrients to be used by
  plants and animals in food chain
• Important part of a aquatic ecosystems

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Benthic Macroinvertebrates

• Water quality indicators
• Useful in determining overall health of an
  aquatic ecosystem
• Presence/absence can tell state of the ecosystem
• Poor mobility makes them more susceptible to
  effects of pollution and sedimentation
• Life cycle allows for long term tests to show
  changes in water quality
• Normally very abundant (easy to catch and test)

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Sediment Sampling

• KB corer
• 2 sampling sites
• 3 replicates at each site 6 cores total
• Each core sectioned into 2 cm sections

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Sediment Laboratory Analysis

• 3 replicates of each 2 cm section
• The samples were dried at 50 C
• The samples were fired at 500 C
• At each step the sediment samples were weighed
• The result was an organic matter value and a
  water content value for each 2 cm sediment section

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Benthic Macroinvertebrate Sampling

• Eckman dredge (area225cm²)
• 2 sampling sites
• 3 replicates at each site 6 samples
• Samples were strained through a 80 µm sieve
• Samples were then fixed with formalin

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Benthic Macroinvertebrate Laboratory Analysis

• Each sample was split using a Folsom plankton
  splitter to ¼ of the total amount of
  invertebrates
• Each ¼ sample was counted completely using a
  specimen microscope
• From the total counts, a single species per
  meter² and an overall macroinvertebrates per m²
  were calculated

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Sediment Results Graph
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Sediment Results

• Site 1
• Water content
• 72.6 in the top 2 cm
• 44.2 at a depth of 8 to 10 cm
• Organic matter
• 11.2 to 7.5 over the same depths
• Site 2
• Water content
• 74.0 in the top 2 cm
• 35.3 in the 8 to 10 cm depth
• Organic matter
• 10.7 to 6.0 over the same depths

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Explanation of Results

• Typical water content for lake systems
• 85 decreasing to 75 for up to 15 cm
• Water content at the pond was less
• Variation due to high erosion in agricultural
  area
• Typical organic matter content for pond systems
• Approximately 5
• Organic matter content at the pond was as high as
  11.2
• Variation due to shallow system and surrounding
  agricultural land

(Perry and Taylor, 2007)
(Avnimelech et al., 2001)
(Wetzel, 2001)
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Benthic Macroinvertebrates Graph
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Bethic Macroinvertebrates Results

• Site 1
• Chaoborus- 13,866 per m²
• Chironomids- 889 per m²
• Oligochaetes- 3,556 per m²
• Ceratopogonidae- 1,600 per m²
• Total Bethic Macroinvertebrates
• 19,911 per m²

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Benthic Macroinvertebrates Results

• Site 2
• Chaoborus- 14,814 per m²
• Chironomids- 12,800 per m²
• Oligochaetes- 652 per m²
• Ceratopogonidae- 178 per m²
• Total Benthic Macroinvertebrates
• 28,444 per m²

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Explanation of Results

• High benthic macroinvertebrate densities
• Fish unable to forage for these due to sediment
  accumulation

(Schofield et al., 2004)
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Summary

• High organic matter content
• Low water content
• High number of benthic macroinvertebrates
• Moderate levels of sediment accumulation

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References

• Avnimelech, Yorarn. "Water content, organic
  carbon and dry bulk density in flooded
  sediments." Aquacultural Engineering 25. 1Aug.
  2001 25-33. lthttp//www.sciencedirect.com/science?
  _obArticleURL_udiB6T4C-436VYN7-3_user854313_
  coverDate082F312F2001_rdoc1_fmt_origsearc
  h_sortdviewc_acctC000046079_version1_urlV
  ersion0_userid854313md53ce23f2e783adbde911e90
  bd76e56987gt.
• Fairchild, G. Winfield (2004 January).
  Ecologically Based Small Pond Management.
  Pennsylvania Department of Environmental
  Protection, from http//www.p2pays.org/ref/40/3987
  0.pdf
• "Freshwater Benthic Macroinvertebrates, Useful
  Indicators of Water Quality." Maryland Department
  of Natural Resources. 06 may 2004. Maryland DNR.
  28 Nov 2007 lthttp//www.dnr.state.md.us/streams/pu
  bs/freshwater.htmlgt.
• Leppa, Markus, Haikki Hamalainen, and Juha
  Karjalainen. "The response of benthic
  macroinvertebrates to whole-lake
  biomanipulation." Hydrobiologia 498(2003)
  97-105.
• Madej, Mary Ann. "The role of organic matter in
  sediment budgets in forested terrain."Sediment
  Budgets 2. 292. 2005.
• Perry, Chris, and Kevin Taylor. Environmental
  Sedimentology. 1st. United Kingdom Blackwell
  Publishing, 2007.
• Wetzel, R. G. 2001. Limnology - Lake and River
  Ecosystems (3rd ed) Academic Press p. 518.
• Schofield, Kate A., Pringle, Catherine M. and
  Meyer, Judy L. Effects of increased bedload on
  algal- and detrital-based stream food webs
  Experimental manipulation of sediment and
  macroconsumers. Limnology and Oceanography
  49(4). 2004. p. 900-909.

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Questions

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