patterns of eutrophication in lake matoaka

Patterns of Eutrophication in Patterns of Eutrophication in Patterns of Eutrophication in Patterns of Eutrophication in Lake MatoakaLake MatoakaLake MatoakaLake MatoakaWilliamsburg, VAWilliamsburg, VAWilliamsburg, VAWilliamsburg, VA

Lindsay Schwarting, Clarkson University

Dr. Randolph Chambers, College of William & Mary

REU Summer 2007

*Thanks to Mindy Forsyth for being my photographer*

IntroductionIntroductionIntroductionIntroduction

• Eutrophic watersheds– High organic productivity

– ‘Well-fed’ in phosphorus and nitrates

– Murky water depleted in oxygen

• Chlorophyll• Chlorophyll– Energy fixation in photosynthesis

– Assessment of algal biomass in lakes/ponds

– Accurate measure of photosynthetic activity

– Depends on availability of nutrients

ObjectivesObjectivesObjectivesObjectives• Develop a technique for measuring algal chlorophyll Develop a technique for measuring algal chlorophyll Develop a technique for measuring algal chlorophyll Develop a technique for measuring algal chlorophyll concentration in Lake Matoakaconcentration in Lake Matoakaconcentration in Lake Matoakaconcentration in Lake Matoaka

• Establish any patterns of anoxic zonesEstablish any patterns of anoxic zonesEstablish any patterns of anoxic zonesEstablish any patterns of anoxic zones

• Determine whether or not there are spatial/temporal/depth Determine whether or not there are spatial/temporal/depth Determine whether or not there are spatial/temporal/depth Determine whether or not there are spatial/temporal/depth gradients of chlorophyll within the lakegradients of chlorophyll within the lakegradients of chlorophyll within the lakegradients of chlorophyll within the lake– Hypothesis: Eastern side of the lake would have greater amounts of algae (and – Hypothesis: Eastern side of the lake would have greater amounts of algae (and therefore chlorophyll) due to the higher amounts of development-associated runoff

Materials & MethodsMaterials & MethodsMaterials & MethodsMaterials & Methods

!(

!(

!(

BerkeleyBerkeleyBerkeleyBerkeley

College CreekCollege CreekCollege CreekCollege Creek

3333

2222

1111

¯

!(!(

!(

!(

!(!(

!(

!(

!(

StrawberryStrawberryStrawberryStrawberry

PogoniaPogoniaPogoniaPogonia

Crim DellCrim DellCrim DellCrim Dell

99998888

7777

6666

55554444

12121212

11111111

10101010

Lake MatoakaLake MatoakaLake MatoakaLake Matoaka

Materials & MethodsMaterials & MethodsMaterials & MethodsMaterials & Methods

• Field measurements– Temperature

– DO2

– Conductivity

• Filtration

• Spectrophotometric methods• Spectrophotometric methods

depth (m)

depth (m)

depth (m)

depth (m)

-1

0

1

2

Results:Results:Results:Results:Depth Patterns

average temperature (C)average temperature (C)average temperature (C)average temperature (C)

0 5 10 15 20 25 30 35

depth (m)

depth (m)

depth (m)

depth (m)

2

3

4

•no significant thermocline

•even mixing of water

Results:Results:Results:Results:Depth Patterns

depth (m)

depth (m)

depth (m)

depth (m)

-1

0

1

2

depth (m)

depth (m)

depth (m)

depth (m)

-1

0

1

2

[chlorophyll] ([chlorophyll] ([chlorophyll] ([chlorophyll] (µµµµg/L)g/L)g/L)g/L)

0 20 40 60 80 100

depth (m)

depth (m)

depth (m)

depth (m)

2

3

4

DODODODO2222 (mg/L) (mg/L) (mg/L) (mg/L)

0 2 4 6 8 10 12depth (m)

depth (m)

depth (m)

depth (m)

2

3

4

•decomposition > photosynthesis

Results:Results:Results:Results:Temporal Patterns

[Chlorophyll] (

[Chlorophyll] (

[Chlorophyll] (

[Chlorophyll] ( µµ µµg/L)

g/L)

g/L)

g/L)

20

30

40

50

60

temperature (C)

temperature (C)

temperature (C)

temperature (C)

10

15

20

25

30

35

datedatedatedate

6/11

/07

6/18

/07

6/25

/07

7/2/07

7/9/07

7/16

/07

[Chlorophyll] (

[Chlorophyll] (

[Chlorophyll] (

[Chlorophyll] (

0

10

datedatedatedate

6/11

/07

6/18

/07

6/25

/07

7/2/07

7/9/07

7/16

/07

0

5

•seasonal variation due to nutrient limitation

Results:Results:Results:Results:Spatial Patterns

[chlorophyll] (

[chlorophyll] (

[chlorophyll] (

[chlorophyll] ( µµ µµg/L)

g/L)

g/L)

g/L)

20

40

60

80

!(

!(

!(



3333

2222

1111

¯

locationlocationlocationlocation

0 1 2 3 4 5 6 7 8 9 10 11 12 13

0

College Creek 0.030 m3/s

Crim Dell 0.012 m3/s

Strawberry 0.008 m3/s

Pogonia 0.006 m3/s

Berkeley 0.005 m3/s

Table 1. Runoff into Lake Matoaka!(

!(

!(

!(

!(!(

!(

!(

!(





99998888

7777

6666

55554444

12121212

11111111

10101010


Results:Results:Results:Results:Spatial Patterns

conductivity (

conductivity (

conductivity (

conductivity (

µµ µµS)S) S)S)

100

200

300

400

500

!(

!(

!(



3333

2222

1111

¯

locationlocationlocationlocation

0 1 2 3 4 5 6 7 8 9 10 11 12 13

conductivity (

conductivity (

conductivity (

conductivity (

0

100

•correlation between conductivity and runoff volume

!(!(

!(

!(

!(!(

!(

!(

!(





99998888

7777

6666

55554444

12121212

11111111

10101010


ResultsResultsResultsResults

temperature (C)

temperature (C)

temperature (C)

temperature (C)

22

24

26

28

30

32

34

temperature (C)

temperature (C)

temperature (C)

temperature (C)

22

24

26

28

30

32

34r2 = .35 r2 = .37

[chlorophyll] ([chlorophyll] ([chlorophyll] ([chlorophyll] (µµµµg/L)g/L)g/L)g/L)

0 20 40 60 80 100 120

20

DODODODO2222 (mg/L) (mg/L) (mg/L) (mg/L)

0 2 4 6 8 10 12 14 16

20

•high chlorophyll and low DO2

at cold temperatures

•decomposition is occurring faster than photosynthesis

•warmer water near the surface receives more oxygen from atmosphere

•colder water at bottom has more respiration and decomposition

ConclusionsConclusionsConclusionsConclusions

•Chlorophyll concentration and conductivity correlates directly w. runoff volume

•Lake Matoaka as a large-scale BMP?

EutrophicEutrophicEutrophicEutrophic

Chlorophyll (Chlorophyll (Chlorophyll (Chlorophyll (µµµµg/L)g/L)g/L)g/L) >15

Phosphorus (Phosphorus (Phosphorus (Phosphorus (µµµµg/L)g/L)g/L)g/L) >15

Table 2. Lake Matoaka as a eutrophic system

Phosphorus (Phosphorus (Phosphorus (Phosphorus (µµµµg/L)g/L)g/L)g/L) >15

Depth (m) and Depth (m) and Depth (m) and Depth (m) and sedimentsedimentsedimentsediment

<10, organic bottom high in N

Source. Berner, E. Global Environment. p 251.

ReferencesReferencesReferencesReferences

1. Berner, E. Global Environment: Water, Air, and Geochemical Cycles. Prentice Hall. NJ. pp 247-260. 1996.

2. Lorenzen, C. 1967. Determination of Chlorophyll and Pheo-Pigments: Spectrophotometric Equations. Limnology and Oceanography 12: 343-346.

3. Lorenzen, C. 1970. Surface Chlorophyll as an Index of the Depth, Chlorophyll Content, and Primary Productivity of the Euphotic Layer. Limnology and Oceanography 15: 479-480.Limnology and Oceanography 15: 479-480.

4. Nelson, D. 1960. Improved Chlorophyll Extraction Method. Science 132: 351.

5. Oviatt, C. et al. 1986. Patterns of productivity during eutrophication. Marine Ecology 28: 69-80.

6. Wetzel, R. Limnology 2nd Ed. Saunders College Publishing. PA. 1983.

7. Yentsch, C. 1957. Short-Term Variations in Phytoplankton Chlorophyll and Their Significance. Limnology and Oceanography 2: 140-142.

patterns of eutrophication in lake matoaka

Documents