Update on Phosphorus and Cladophora in the Lake … Quality/Bootsma...1 Update on Phosphorus and...

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1 Update on Phosphorus and Cladophora in the Lake Michigan Nearshore Zone Harvey Bootsma 0 5 10 15 20 25 30 1980-84 1985-89 1990-94 1995-99 2000-05 [P] ( μ g L -1 ) Total Dissolved P Total P 14.5 9.5 19.4 7.8 11.7 6.9 12.6 8.2 11.9 12.5 Nearshore TP and TDP Concentrations Since 1980, Near Milwaukee Harbor

Transcript of Update on Phosphorus and Cladophora in the Lake … Quality/Bootsma...1 Update on Phosphorus and...

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Update on Phosphorus and Cladophora in the Lake Michigan

Nearshore Zone

Harvey Bootsma

0

5

10

15

20

25

30

1980-84 1985-89 1990-94 1995-99 2000-05

[P] (μ

g L-1

)

Total Dissolved PTotal P

14.5

9.5

19.4

7.8

11.7

6.9

12.6

8.2

11.912.5

Nearshore TP and TDP Concentrations Since 1980,

Near Milwaukee Harbor

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Spring Total P(mean of all pelagic stations)

0

1

2

3

4

5

6

719

8319

8419

8519

8619

8719

8819

8919

9019

9119

9219

9319

9419

9519

9619

9719

9819

9920

0020

0120

0220

0320

0420

05

Tota

l P ( μ

g/L) Michigan

Huron

GLWQA Target for Lake Michigan: 7 μg/L

0

0.05

0.1

0.15

0.2

0.25

0.3

1 /1 /8 2 1 /1 /8 3 1 /1 /8 4 1 2 /3 1 /8 4 1 /1 /8 6 1 /1 /8 7 1 /1 /8 8 1 2 /3 1 /8 8 1 /1 /9 0 1 /1 /9 1 1 /1 /9 2 1 2 /3 1 /9 2 1 /1 /9 4 1 /1 /9 5 1 /1 /9 6 1 2 /3 1 /9 6 1 /1 /9 8 1 /1 /9 9 1 /1 /0 0 1 2 /3 1 /0 0 1 /1 /0 2

mg/

L

SRP

TP

82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01

20-Year Phosphorus Trend at River Junction

Data Source: MMSD

3

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

1980 1985 1990 1995 2000 2005

Dis

solv

ed P

: To

tal P

Rat

io

In Milwaukee River, dissolved P is becoming a larger fraction of TP

0

1

2

3

4

5

1970 1975 1980 1985 1991 1994 1995

Ave

rage

[P] (

ppm

)So

il P

Stor

age

Cha

nge

(kg

ha-1

)

P in Wisconsin Cropland

Bundy and Sturgul 2001

0102030405060

1968-73

1974-77

1978-81

1982-85

1986-90

1991-94

1995-99

4

SRP (μg L-1)

Milwaukee River Transect, April 2005

0 20 40 60 80

1

2

3

4

5

6

7

8

9

10

infotrek.er.usgs.gov/.../ milwaukeemap.gif

0

50

100

150

200

250

J F M A M J J A S O N D

0

50

100

150

200

250

J F M A M J J A S O N D

0

50

100

150

200

250

J F M A M J J A S O N D

J F M A M J J A S O N D

J F M A M J J A S O N D

1982-87Mean = 102

1988-95Mean = 72

1996-2001Mean = 120

Tota

l P (μ

g L-

1 )

Milwaukee River TP Concentrations have increased in late spring.

5

0

5

10

15

20

25

30

35

40

J F M A M J J A S O N D

0

5

10

15

20

25

30

35

J F M A M J J A S O N D

0

5

10

15

20

25

30

35

J F M A M J J A S O N D

m3

s-1

1982-87Avg. = 18.4

Milwaukee River Discharge

1996-2001Avg. = 14.3

1988-95Avg. = 13.1

0

5

10

15

20

25

1981 1986 1991 1996 2001

Annual Means

Data source: USGS

6

10 km

Milw

aukee R.

Kinnickinnic R.

Menomonee R.

10 km

Milwaukee regionNearshore Phosphorus loads,

May – July 2006

Cladophora

zone

River load:120 mg P m-2

Mussel Excretion:506 mg P m-2

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The Lake Michigan The Lake Michigan Phosphorus CyclePhosphorus Cycle

P Load

OutflowPhytoplankton

Fish

Zooplankton

Burial

DPDP

Nearshore Loop Offshore

Loop

Musselinvasion

Mussels have made nearshore water clear

Source: MMSD

8

November 2007

November 2008

9

0

1

2

3

4

5

6

7

8

9

10TD

P (m

g/L)

May June July Aug. Sep. Oct.

20062007

2008

Near-Bottom Total Dissolved Phosphorus

Atwater, Lake Michigan

TDP

(μg/

L)

0

5

10

15

20

25

Tem

pera

ture

(o C)

Apr May Jun Jul Aug Sep Oct Nov

2006

2008

Water Temperature at 9 m

10

4

5

6

7

8

9

10

11

12

13

14

1970 1975 1980 1985 1990 1995 2000 2005

June

- A

ugus

t Mea

n T

(o C)

Lake Michigan Nearshore

Summer Temperature TrendOptimum for Cladophora growth

no Cladophora growth

TEMPERATURE

PHOSPHORUS

CladophoraQuagga Mussel

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00.0020.0040.0060.008

0.010.0120.0140.0160.018

0.02

0 5 10 15 20 25 30

Food Concentration (mg P ml-1)

μgP

mgD

W-1

hr-1

Lab Experiments:

Phosphorus Excretion by Quagga Mussels

10oC

15oC

22oC

0

50

100

150

200

250

300

350

400

0 5 10 15 20 25 30 35Temperature (oC)

Bio

mas

s (g

DW

m-2

)

00.020.040.060.080.10.120.140.160.180.2

Gro

wth

Rat

e (d

ay-1

)

B

μ no mussels

mussels

12

LIGHT ?

-0.1

-0.05

0

0.05

0.1

0.15

0.2

Clean Mussels Dirty Mussels Mussels + Cladophora

P Flux Between Mussels and Cladophora

μg P

mus

sel-1

hr-1

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Current Needs

3. What is the botulism mechanism?

Photo: Alice Van Zoeren

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4 minutes

after dye injection

15

above mussels

mussel bed

K = 0.1 cm2 s-1

K = 0.01 cm2 s-1

0

0.2

0.4

0.6

0.8

1

1.2

-1000 1000 3000 5000 7000

O2 uptake rate (mg m-2 d-1)

Dep

th o

f ano

xic

zone

in m

usse

l bed

Effect of benthic respiration on thickness of anoxic layer

16

17

77.5

88.5

99.510

0 50 100

Time (minutes)

DO

(% S

at.)

Benthic O2 uptake by mussels

5,258 mg O2 m-2 d-1

0

0.2

0.4

0.6

0.8

1

1.2

-1000 1000 3000 5000 7000

O2 uptake rate (mg m-2 d-1)

Dep

th o

f ano

xic

zone

in m

usse

l bed

(cm

)

Effect of benthic respiration on thickness of anoxic layer

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above mussels

mussel bed

K = 0.1 cm2 s-1

K = 0.01 cm2 s-1

Underwater Particle Image Velocimetry

(PIV) System

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PIV Image Analysis Results

Qian and Bootsma, in press

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0

10

20

30

40

50

60

0 10 20 30 40 50

[SRP] (nmol l-1)

Hei

ght (

mm

)

Vertical Soluble Reactive Phosphorus ProfileOver Mussel Bed

dzdcDF =

The Cladophora Solution

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Bruce Mozert / University of Florida Press