Great Lakes Cladophora Into the 21 st Century: Same Alga – Different Ecosystem.

Great Lakes CladophoraInto the 21st Century:

Same Alga – Different Ecosystem

dXR L X

dt

Cladophora in the Great Lakes

• Cladophora is a filamentous green alga, first identified in Lake Erie in 1848.

Image at left from http://www.mlswa.org/UnderWaterPlantGuide/cladophora.htm

http://www.mlswa.org/UnderWaterPlantGuide/cladophora.htm

http://www.mlswa.org/UnderWaterPlantGuide/cladophora.htm


• Windrows of sloughed Cladophora were known from Lake Erie in the 19th century.

Image from Taft and Kishler (1973)


• Nuisance growth of Cladophora was prevalent in Lake Ontario by the late 1950s.


• Problems were also encountered in Lake Michigan.


• Great Lakes Water Quality Agreement of 1972

Five of the six goals set forth under Annex 3, Control of Phosphorus, relate to nuisance algal growth.

Image by Richard Lorenz


• Awakening

“Cladophora in the Great Lakes”H. Shear and D.E. Konasewich

Great Lakes Research Advisory BoardInternational Joint Commission, 1975

“I wish I could inundate you with pictures … pictures of bikini-clad young lovelies standing waste deep in certain waters … ten pounds of green stringy material festooning their otherwise delightful limbs … the only stimulus needed to complete your abhorrence of the situation would be the accompanying flies and pig-pen odor which go hand-in-hand with rotting protein. Gentlemen, Cladophora is a big problem.

Carlos M. Fetterolf, Jr.Executive Secretary, Great Lakes Fisheries Commission


• Research Initiatives

monitoringmonitoringexperimentexperimentationationmodelingmodelingmanagememanagementnt

Project Objectives

• identify growth-mediating environmental factors

• develop algorithms describing those relationships

• incorporate algorithms in a mechanistic model

• test model in a demonstration program

• apply model to determine limiting nutrient levels

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Study Site

• Harbor Beach, Lake Huron

• regional nearshore has little or no Cladophora

• severe local impact due to P point source

Lekan and Coney 1982

Local Conditions

• point source of nutrients

Local Conditions

• gradients in light, phosphorus and biomass

Distance From Nutrient Source (km)

0.25 0.00 0.25 0.50 0.75 1.00

250

200

150

100

50

0Bio

mass

(gD

W•m

-2)

100

80

60

40

20

00.25 0.00 0.25 0.50 0.75 1.00

Dis

solv

ed P

(g

P•L-

1)

0.25 0.00 0.25 0.50 0.75 1.00

0.6

0.4

0.2

0.0

Sto

red

P (

%D

W)

145

The Model

• mass balance approach

• three state variables

- dissolved phosphorus, P

- stored phosphorus, Q

- Cladophora biomass, X

Rock Creek

Spring CreekWWTP Effluent

dXR L X

dt

dQQ

dt

ij ij i i i i

dPV a P X A W

dt

Conceptual Framework

DissolvedPhosphorus

StoredPhosphorus

CladophoraBiomass

Loading Exchange

Uptake

SaturationFeedback

Loss toSloughing

Loss toRespiration

CarryingCapacityFeedback

Light and Temperature

Mediation

Modeling P(dissolved P)

• source/sink terms:

- loading, W

- uptake by Cladophora, • X • A

- mass transport, aij

ij ij i i i i

dPV a P X A W

dt

Modeling Q(stored P)


- gain through uptake, - loss to growth partitioning, • Q

StoredPhosphorus

Uptake

SaturationFeedback

Demand for

Growth

dQQ

dt

Modeling (P uptake)

• uptake as mediated by:

- dissolved P

- stored P

- temperature,

P u

pta

ke (

% P

per

day)

3.0

0.0

Q = 0.12%

Q = 0.23%

0 200 400 600 800

2.0

1.0

Dissolved Phosphorus (gPL-1)

Maxim

um

P u

pta

ke (

% P

d-1)

3.0

0.00.0 0.2 0.4 0.6 0.8 1.0

2.0

1.0

Stored Phosphorus (%P)

max* = 4.5 %P•d-1

Kq = 0.07 %P4.0

*

0

q

m q

KP

K P K Q Q

Modeling X(biomass)


- gain through growth, - loss to respiration, R

- loss to sloughing, L

dXR L

dt

Modeling (growth)

• growth mediating functions:

- light and temperature, f (I,T)

- stored P, f (Q)

- carrying capacity, f (X)

,f I T f Q f X

Modeling (growth)



- stored P, f (Q)


21 2 3 4 5

2 3 2 2 36 7 8 9 10

4 3 2 2 3 411 12 13 14 15

( , )f I T a a T a I a T a TI

a I a T a T I a TI a I

a T a T I a T I a TI a I

Modeling (growth)



- stored P, f (Q)


Net

Speci

fic

Gro

wth

Rate

(d

-1)

0.6

0.00.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

0.4

0.2

Stored Phosphorus (%P)

0.8

0( ) 1Q

f QQ

Modeling (growth)



- stored P, f (Q)


max

( ) 1X

f XX

Modeling R(respiration)

• basal (dark) and light-enhanced

- basal, f (,T)

- light-enhanced, f (I,T)

21 2 3 4 5

2 3 2 2 36 7 8 9 10

4 3 2 2 3 411 12 13 14 15

( , )f I T b b T b I b T b TI

b I b T b T I b TI b I

b T b T I b T I b TI b I

0.151 0.025 0.1basalR T

( , ) (1 )basalR f I T PP R PP

Modeling L(sloughing)

• varies with wind and biomass, f (w,X)

300

200

100

0Bio

mass

(gD

W•m

-2)

M J J A S O

400

= wind event

3.4 1.7611.1 433

XL

Demonstration Program (nutrient management)

• supporting model calibration and verification

- calibration: conditions prior to treatment

- verification: conditions following treatment

Model Calibration and Verification

0.0 0.5 1.0 1.5 2.0

(147)

Ph

osp

horu

s (µ

gP∙L-

1) 60

40

20

0

Distance from nutrient source (km)

0.0 0.5 1.0 1.5 2.0

Ph

osp

horu

s (µ

gP∙L-

1) 60

40

20

0


0.0 0.5 1.0 1.5 2.0

Sto

red

P (%

DW

)

0.6

0.4

0.2

0.0


0.0 0.5 1.0 1.5 2.0

Sto

red

P (

%D

W)


0.6

0.4

0.2

0.0Q0 Q0

0.0 0.5 1.0 1.5 2.0

Bio

mass

(g

DW

∙m

-2) 300

200

100

0


0.0 0.5 1.0 1.5 2.0

Bio

mass

(g

DW

∙m

-2) 300

200

100

0


BeforeP-removal

AfterP-removal

System Response (to nutrient management)

BEFORE P-removal

AFTER P-removal


BEFORE P-removal

gro

wth

rate

stored phosphorus

sensitive

insensitive


AFTER P-removal

gro

wth

rate

stored phosphorus

sensitive

insensitive


3000

2000

1000

0seasonal

productionstanding

crop

Cla

dop

hora

(gD

W•m

-2)

Use In Design (nutrient management and offshore discharge)

Shoreline

outfalllength

Nuisance growth of Cladophora, defined as a standing crop of >50 gDW∙m-2, can be prevented if soluble reactive phosphorus concentrations are kept below 2 μgP∙L-1.

Canale and Auer 1982


Image from http://www.coam.org.uk/Events/may.htm

1985 – 2005The “Dark Age of Cladophora”

http://www.coam.org.uk/Events/may.htm

http://www.coam.org.uk/Events/may.htm

Why Cladophora? Why Now?

Public perception of Great Lakes water quality is based, in large part, on the experience at the land-water interface.

Rock Point Provincial Park, Lake Erie.Image by Scott Higgins.

Bradford Beach, Lake MichiganImage provided by Harvey Bootsma.

Coronation Beach, Lake Ontario.Image by Sairah Malkin

• one million gallons of lake water pass through the plant every 3 minutes, sucked in by 3 giant pumps, and filtered on moving, fence-like screens that rotate inside minivan-sized structures.

• the plant was shut down 3 times in September and October 2007 as Cladophora clogged filters; • the shutdown costs the plant between $1.5 million and $2 million a day in lost revenue.

James A. FitzPatrick Nuclear Power Plant, Lake Ontario

Growth Mediating Conditions: Phosphorus

Changes in phosphorus change standing crop but have a lesser impact on depth of colonization.

0.0

0.2

0.4

0.6

0.8

1.0

0 2 4 6

Depth (m)

Cla

do

ph

ora

Gro

wth

Po

ten

tia

l

decreasingphosphorusconcentration

Response to P Loading Reductions

Lake Ontario

Model output generally consistent with the observations of Painter and Kamaitis (1985).

0

2

4

6

8

10

12

14

16

1965 1975 1985 1995 2005

SR

P (

µg

P∙L

-1)

0.0

0.2

0.4

0.6

0.8

1.0

0 2 4 6

Depth (m)

Cla

do

ph

ora

Gro

wth

Po

ten

tial

Not Your Grandmother’s Ecosystem

Image by Sairah Malkin

Go down MosesGo down to Egypt landTell old PharaohSet my people free.

African-American Spiritual

Moses?

Same Lakes – Different Ecosystem

What Changed?Annual Secchi Disk Data For Outer Harbor Site 13

Se

cc

hi (M

ete

rs)

Median 25%-75% Non-Outlier Range

OH-13

19901991

19921993

19941995

19961997

19981999

20002001

20020

1

2

3

4

5

6

7

8

9

10

Data for Milwaukee Harbor monitoring site provided by Harvey Bootsma.

Lake Michigan, Milwaukee Harbor

The depth of the photic zone, i.e. the 1% light level, has increased by 6m, on average, in Lakes Erie, Michigan and Ontario.

Growth Mediating Conditions: Light

Changes in the underwater light environment impact the depth of colonization.

0.0

0.2

0.4

0.6

0.8

1.0

0 2 4 6 8 10 12

Depth (m)

Cla

do

ph

ora

Gro

wth

Po

ten

tia

l

Pre- and Post-DreissenidTransparency

19867m depth, off Chicago

200113m depth, off Milwaukee

Images from http://www.glwi.uwm.edu/research/aquaticecology/cladophora/

Courtesy of John Janssen

http://www.glwi.uwm.edu/research/aquaticecology/cladophora/

Response to Increased Transparency

The increase in growth potential is driven by an increased depth of colonization, with Cladophora occupying solid substrate at depths 3.0 – 4.5 m deeper than in the pre-dreissenid period.

Effect of Extinction Coefficient

0

10

20

30

40

50

60

Lake Erie Lake Michigan Lake Ontario

Ch

ang

e in

Cla

do

ph

ora

G

row

th P

ote

nti

al (

%)

Combined Response

The net effect is that gains achieved through reductions in phosphorus loading have been offset by dreissenid-driven improvements in the underwater light environment and attendant colonization of new habitat by Cladophora.

Combined Effect

0

10

20

30

40

50

60

70

80

Lake Erie Lake Michigan Lake Ontario

Ch

an

ge

in C

lad

op

ho

ra

Gro

wth

Po

ten

tia

l (%

)

And If That’s Not Enough …

Image from http://www.glwi.uwm.edu/research/aquaticecology/cladophora/

Hecky et al. (2004) describe the role of zebra mussels as ‘ecosystem engineers’, creating a nearshore phosphorus shunt that can stimulate Cladophora growth.




So What To Do?

In the 1960sIn the 1980sIn the Dark Age of Cladophora

Images from http://www.azote.se/index.asp?sa=30&str=Camilla%20Bollner&t=71&b=1&lb= and

http://focus.nigz.nl/index.cfm?act=info.summary&varrub=7

http://www.azote.se/index.asp?sa=30&str=Camilla%20Bollner&t=71&b=1&lb=








20 Years of Footprints in the Cladophora

20051985

The failure to maintain the biological integrity of the nearshore areas of four of the five Great Lakes needs to be addressed.

Review Working Group [D]Draft Final Report, September 2006

Great Lakes Cladophora Into the 21 st Century: Same Alga – Different Ecosystem.

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