Blue Lake AssessmentLimnology Fall 2010

Ian FaurotElise LaVanaway

Scott ParadisCody Settles

What we knowSmall, circular lake

with rapid drop-offNo inflow, year-round

outflowFrozen in winterAbundant population

of bullhead (Ameiurus sp.) and a stocked rainbow trout population

Extensive macrophytes

What we want to learnLake classification and originsProductivitySediment compositionHabitat qualityBiological communityPotential concerns

What we need to sampleTo 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

A

B

D

C

Study Area•East side of lake

•4 sampling sites

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

Methods and Materials: Physical properties

Photic zone/irradience

Temperature

Oxygen content

Conductivity

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.

Bathymetric Map

Volume – 58877 m3 Sediment volume – 6873 m3 Surface area – 10532 m2

Maximum depth – 10.22 mMean depth - 5.59 mSediment depth - .57m

Photic zoneSecchi depth –

2 m

Li-cor photometer estimate of photic zone – 5.69 m

Extinction coefficient – 0.81

0 20 40 60 80 100 120 1400

1

2

3

4

5

6

7

Irradience

Dep

th

Temperature profileMean

temperature – 8.99 °C

Expect inverse stratification in winter

Direct stratification in summer

5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 100

2

4

6

8

10

12

Temperature (°C)

Dep

th

Dissolved oxygenSomewhat

low for good trout habitat

Potentially a problem with anoxia

0 0.5 1 1.5 2 2.5 3 3.5 40

2

4

6

8

10

12

Dissolved Oxygen (mg/L)

Dep

th

Specific conductivityMeasured in

micro-seimens per cm.

A measure of TDS

200 220 240 260 280 300 320 340 360 380 4000

2

4

6

8

10

12

Conductivity (µS)

Dep

th

Chlorophyll-a Chlorophyll levels

seem moderate

Little significant variation across lake

0

0.5

1

1.5

2

2.5

3

3.5

4

Chl-a concentrations (µg/L)

ABCDAVG

ConclusionsBlue lake formed by glacial activity

Kettle LakeMesotrophic, Dimictic classification

Chlorophyll A 3.16 ± 0.94 µg/LTP: 16.94 ± 10.81 µg/L, SP: 16.73 ± 10.07 µg/LTemp: 8.99 °CDO: 2.93 mg/LOrganic sediment content slightly higher than

mineral content

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 CascadeContinue study on lake in spring/summer

Oxygen levels

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.