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Blue Lake Assessment Limnology Fall 2010

Blue Lake Assessment Limnology Fall 2010. Ian Faurot Elise LaVanaway Scott Paradis Cody Settles. What we know. Small, circular lake with rapid drop-off No inflow, year-round outflow Frozen in winter Abundant population of bullhead ( Ameiurus sp. ) and a stocked rainbow trout population

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Blue Lake Assessment Limnology Fall 2010

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  1. Blue Lake AssessmentLimnology Fall 2010 Ian Faurot Elise LaVanaway Scott Paradis Cody Settles

  2. What we know • Small, circular lake with rapid drop-off • No inflow, year-round outflow • Frozen in winter • Abundant population of bullhead (Ameiurus sp.) and a stocked rainbow trout population • Extensive macrophytes

  3. What we want to learn • Lake classification and origins • Productivity • Sediment composition • Habitat quality • Biological community • Potential concerns

  4. What we need to sample • To assess Blue Lake, we need • Physical parameters: bathymetric map, irradience, temperature, maximum and mean depth, water and sediment volume, sediment profile and composition • Chemical parameters: total and dissolved phosphorous*, specific conductivity, and dissolved oxygen profiles • Biological parameters: primary production, zooplankton community, littoral and benthic invertebrates

  5. Study Area • East side of lake • 4 sampling sites D A C B

  6. Methods and Materials: Bathymetry • A boat with a depth finder and GPS was taken in even transects across the lake, north to south and east to west, to obtain a bathymetric profile

  7. Methods and Materials: Physical properties • Photic zone/irradience • Temperature • Oxygen content • Conductivity

  8. Methods and Materials : Chlorophyll • Only photic zone sampled • 3 replicates of integrated samples at our 4 sites • Chlorophyll calculated with photo-spectrometer BF Environmental Consultants Inc.

  9. Bathymetric Map Maximum depth – 10.22 m Mean depth - 5.59 m Sediment depth - .57m Volume – 58877 m3 Sediment volume – 6873 m3 Surface area – 10532 m2

  10. Photic zone • Secchi depth – 2 m • Li-cor photometer estimate of photic zone – 5.69 m • Extinction coefficient – 0.81

  11. Temperature profile • Mean temperature – 8.99 °C • Expect inverse stratification in winter • Direct stratification in summer

  12. Dissolved oxygen • Somewhat low for good trout habitat • Potentially a problem with anoxia

  13. Specific conductivity • Measured in micro-seimens per cm. • A measure of TDS

  14. Chlorophyll-a • Chlorophyll levels seem moderate • Little significant variation across lake

  15. Conclusions • Blue lake formed by glacial activity • Kettle Lake • Mesotrophic, Dimictic classification • Chlorophyll A 3.16 ± 0.94 µg/L • TP: 16.94 ± 10.81 µg/L, SP: 16.73 ± 10.07 µg/L • Temp: 8.99 °C • DO: 2.93 mg/L • Organic sediment content slightly higher than mineral content

  16. Recommendations Avoid input of any fuel, fertilizer, sewage. Reduce levels of bullhead – spawn in lake Catch and Keep? Continue to stock rainbow trout Spawning/Trophic Cascade Continue study on lake in spring/summer Oxygen levels

  17. Literature cited • Bettoli, P.W., M.J. Maceina, R.L. Noble, and R.K. Betsill. Response of a reservoir fish community to aquatic vegetation removal. North American Journal of Fisheries Management 13:110-124. • Gall, G.A.E. and P.A. Crandell, 1992. The rainbow trout. Aquaculture 100:1-10. • Wetzel, R. G. 2001. Limnology - Lake and River Ecosystems (3rd ed) Academic Press. • Wilhelm, F. 2010a. Fish 415 Limnology, Spring Valley Lab Handout. University of Idaho, Moscow, Idaho. • Wilhelm, F. 2010b. FISH 415 Limnology, Zooplankton Identification Lab. University of Idaho, Moscow, Idaho.

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