Sediment Depth Accumulation and Benthic Macroinvertebrates

1. Sediment Depth Accumulation and Benthic Macroinvertebrates Tom Chance, John McConnaughey, John Sorensen, Caselle Wood

2. Mr. Ingle’s 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

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

4. Sediment Accumulation • System capacity • Nutrient cycling potential • Fish spawning • Fish foraging • Affect on primary production

5. 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

6. 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)

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

8. 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

9. Benthic Macroinvertebrate Sampling • Eckman dredge (area=225cm²) • 2 sampling sites • 3 replicates at each site = 6 samples • Samples were strained through a 80 μm sieve • Samples were then fixed with formalin

10. 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

11. Sediment Results Graph

12. 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

13. 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 (Wetzel, 2001) (Avnimelech et al., 2001) (Perry and Taylor, 2007)

14. Benthic Macroinvertebrates Graph

15. 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

16. 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

17. Explanation of Results • High benthic macroinvertebrate densities • Fish unable to forage for these due to sediment accumulation (Schofield et al., 2004)

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

19. References • Avnimelech, Yorarn. "Water content, organic carbon and dry bulk density in flooded sediments." Aquacultural Engineering 25. 1Aug. 2001 25-33. <http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T4C-436VYN7-3&_user=854313&_coverDate=08%2F31%2F2001&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000046079&_version=1&_urlVersion=0&_userid=854313&md5=3ce23f2e783adbde911e90bd76e56987>. • Fairchild, G. Winfield (2004 January). Ecologically Based Small Pond Management. Pennsylvania Department of Environmental Protection, from http://www.p2pays.org/ref/40/39870.pdf • "Freshwater Benthic Macroinvertebrates, Useful Indicators of Water Quality." Maryland Department of Natural Resources. 06 may 2004. Maryland DNR. 28 Nov 2007 <http://www.dnr.state.md.us/streams/pubs/freshwater.html>. • 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.

20. Questions ?