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Cortlyn Davies Mitchell Parsons Craig Woodruff.  Zooplankton ◦ Regulate algal population and control algal blooms. ◦ Important food source for planktivorous.

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Presentation on theme: "Cortlyn Davies Mitchell Parsons Craig Woodruff.  Zooplankton ◦ Regulate algal population and control algal blooms. ◦ Important food source for planktivorous."— Presentation transcript:

1 Cortlyn Davies Mitchell Parsons Craig Woodruff

2  Zooplankton ◦ Regulate algal population and control algal blooms. ◦ Important food source for planktivorous fish (e.g. trout).

3  Zooplankton ◦ Regulate algal population and control algal blooms ◦ Important food source for planktivorous fish (e.g. trout)  Macrophytes ◦ Stabilize sediment ◦ Refugium for zooplankton ◦ Produce oxygen through photosynthesis. ◦ Alternate stable states

4  Wisconsin-style closing plankton net  Sampled at 3 locations in the pond  Full water column samples ◦ Triplicates at each site

5  Subsample each collection  Count individuals in subsample  Use counts and volumes to estimate denisty  Average triplicates, then site averages to estimate pond-wide community m7.i.pbase.com/o6/55/932755/1/ DMgpcet.Cyclopoida4.JPG upload.wikimedia.org/wikipedia/com mons/4/4e/Daphnia_pulex.png

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9  Predominantly Cladocerans -> Good for fish  Majority of Cladocerans are Ceriodaphnia -> too small for fish  Many rotifers -> too small for adult fish  Zooplankton density is extremely low ◦ Turnbow Pond: 7 ind/L ◦ Spring Valley: 33 ind/L ◦ Carlson Pond: 1515 ind/L ◦ Dynamite lake (Vanni et al. 1987): 1.4 ind/L (Ceriodaphnia)

10  Fish stock too high, depressing zooplankton population  Hyperpredation due to artificial feeding  No refugium in macrophytes  Feeding can maintain fish, but low zooplankton has other consequences

11  Reduce fish stock  Alter community: Piscivores  Reduce artificial feeding  Establish macrophytes (suggestions to come)

12 Biomanipulation

13  Ten sites in pond body  Three sites in each bay  Eckman grab sampler  Sift and collect macrophytes  Clean and dry  Weigh to estimate density 3x Google Earth

14 Current State: Macrophytes Little macrophyte cover (<1g/m 2 ) – Good for swimming, bad for ecology More in the shallow bays, but still small amount

15  Bank to steep to support macrophyte growth (Duarte and Kalff 1988)  Unable to establish because too little light for photosynthesis  Clearing of all macrophytes when expanded pond

16  More gradual incline on bank  Buffer to reduce turbidity – increase light  Start around edges of pond  Plant emergent macrophytes such as lillies ◦ Same function, more aesthetic  Low growing submerged macrophytes

17  Buffer zone around lake (~50 feet)  Alter fish community ◦ Prevent resuspension via swimming on bottom ◦ Increase zooplankton community  In turn reduces algae density  Establish macrophytes ◦ Prevent sediment resuspension ◦ Provide refuge for zooplankton ◦ Suggest around 50% coverage for diversity and water quality (NRCS 2006 and Hilt et al. 2006)

18  Duarte, C. M., and J. Kalff Influence of lake morphometry of the response of submerged macrophytes to sediment fertilization. Canadian Journal of Fisheries and Aquatic Sciences 45:  Hilt, S., E.M. Gross, M. Hupfer, H. Morcsheid, J. Mählmann, A. Melzer, J. Poltz, S. Sandrock, E. Scharf, S. Schneider, and K. van de Weyer Restoration of submerged vegetation in shallow eutrophic lakes – A guidline and state of the art in Germany. Limnologica 36:  Natural Resource Conservation Service Farm pond ecosystems. Fish and Wildlife Habitat Management Leaflet. No. 29.  Vanni, M. J Effects of nutrients and zooplankton size on the structure of a phytoplankton community. Ecology 68:


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