Environmental control and limnological Environmental control and limnological impacts of a large recurrent spring bloom in impacts of a large recurrent spring bloom in

Lake Washington, USA.Lake Washington, USA.

..ArhonditsisArhonditsis11, M.T.Brett, M.T.Brett11, , D.E. SchindlerD.E. Schindler22 and and J.FrodgeJ.Frodge33

11Department of Civil and Environmental Engineering, Department of Civil and Environmental Engineering, University of Washington, Seattle, USAUniversity of Washington, Seattle, USA

22 Department of Zoology, University of Washington, 404 Department of Zoology, University of Washington, 404 Seattle, Washington, USASeattle, Washington, USA

3 3 King County Department of Metropolitan Services, Seattle, King County Department of Metropolitan Services, Seattle, Washington, USAWashington, USA

Aims of the studyAims of the study

• Quantitative assessment of the spatial vs Quantitative assessment of the spatial vs temporal variabilitytemporal variability

• Identification of the best predictors for Identification of the best predictors for phytoplankton dynamics over the annual phytoplankton dynamics over the annual cyclecycle

Land Uses in the WatershedLand Uses in the Watershed

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0

10

20

30

40

50

60

Time of Year

Depth (m)

8 10 12 14 16 18 20Temperature (°C)

0.00 0.20 0.40 0.60 0.80 1.00

0

10

20

30

40

50

60

Time of Year

Depth (m)

2 4 6 8 10Chlorophyll concentration (µg/L)

-0.04

-0.02

0

0.02

0.04

Vol.

Wt.

Phyto

. G

row

th R

ate

(p

er d

ay

)

6

7

8

9

10

11

12

13

Vol.

Wt.

Tem

peratu

re (

°C

)

0 0.2 0.4 0.6 0.8 1

Time of Year

Lake Washington Phyto. GrowthTemperature

0

1

2

3

4

5

6

7

Vo

l. W

t. C

hlo

ro

ph

yll

Co

nc.

(µ

g/L

)

6

7

8

9

10

11

12

13V

ol.

Wt.

Tem

perau

re (

°C

)

0 0.2 0.4 0.6 0.8 1

Time of Year

Lake Washington ChlorophyllTemperature

Vol

.Wt.

Chl

orop

hyll

(ug/

l)V

ol.W

t. C

hlor

ophy

ll (u

g/l)

Vol

.Wt.

Tem

pera

ture

(oC

)V

ol.W

t. T

empe

ratu

re (

oC)

Temperature

Temperature

Chlorophyll

Phyto GrowthTime of the year

Time of the year

0

5

10

15

Colu

mn 4

6

8

10

12

14

16

Colu

mn 2

84 85 86 87 88 89 90

Column 1

Data #3 Vol. Wt. Chl.

Vol. Wt. Temp.

0

2

4

6

8

10

Biom

ass (

µg C

hla/

l)

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Time of Year

Lake Washington seasonal phytoplankton succession

Others

Cyanos

Greens

Cryptos

Diatoms

1 2 3 4 5 6 7 8 9 10 11 120

100

200

300

400

500

Zo

op

lan

kto

n c

on

cen

trati

on

(u

g d

w/l)

Months

Bosmina Cyclops Daphnia Diaphanosoma Diaptomus Epischura Others

Multivariate Analysis of VarianceMultivariate Analysis of Variance

-0.4

0

0.4

0.8

1.2

1.6

1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999

Chl

oroph

yll (

ug/l)

Raw data Trend

-0.4

0

0.4

0.8

1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999

Chl

oroph

yll (

ug/l)

Seasonal Component

Time Series AnalysisTime Series Analysis

-0.8

-0.4

0

0.4

0.8

1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999

Chl

orop

hyll

(ug/

l)

Irregular Component

Principal Component AnalysisPrincipal Component AnalysisYEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC1975 0.630435 0.47801 0.290486 0.63384 0.985265 0.539066 0.559354 0.74723 0.606657 0.513737 0.382006 0.5857771976 0.626386 0.778422 0.589133 0.377757 0.737294 0.659692 0.598065 0.559365 0.404498 0.390599 0.48718 0.4546831977 0.342483 0.331228 0.347907 0.396789 0.251092 0.3578 0.459778 0.275764 0.411073 0.459997 0.448277 0.5300081978 0.478592 0.5009 0.528612 0.389064 0.245793 0.499619 0.421819 0.515131 0.587201 0.505684 0.169908 0.2916251979 0.415668 0.422184 0.302176 0.538905 0.251006 0.271773 0.256276 0.215011 0.309423 0.377829 0.620712 0.5888371980 0.632074 0.552401 0.565804 0.095344 0.542428 0.520788 0.554989 0.657163 0.282543 0.353099 0.360479 0.1428351981 0.325409 0.397031 0.572133 0.512455 0.871245 0.589991 0.357549 0.394087 0.515926 0.503041 0.291664 0.3638171982 0.178183 0.207406 0.214772 0.23184 0.989157 0.36564 0.405225 0.506815 0.395305 0.499342 0.689397 0.6414341983 0.453007 0.479851 0.382841 0.49939 0.358323 0.287426 0.664499 0.700864 0.495809 0.505173 0.364656 0.3474951984 0.518315 0.467057 0.145688 0.454916 0.554257 0.425527 0.529645 0.508245 0.527187 0.387388 0.172982 0.2623931985 0.306131 0.293819 0.412257 0.333993 0.408809 0.267889 0.275383 0.386487 0.400372 0.345791 0.480578 0.6419631986 0.720705 0.62191 0.531689 0.242995 0.365345 0.551132 0.483242 0.397837 0.429046 0.486168 0.376069 0.321171987 0.279144 0.46327 0.533272 0.520897 0.48382 0.71577 0.329143 0.272259 0.141016 0.236838 0.447618 0.4588061988 0.481399 0.557605 0.342157 -0.04593 0.220416 0.341663 0.559964 0.737675 0.575208 0.48568 0.483267 0.4132841989 0.415845 0.332527 0.334653 0.493121 0.661165 0.414212 0.303309 0.410445 0.376977 0.441129 0.335403 0.4174941990 0.319396 0.13297 0.428332 0.508532 0.588671 0.675162 0.574523 0.545564 0.553818 0.639488 0.588363 0.4703211991 0.522693 0.593979 0.507204 0.637238 0.706895 0.605649 0.703532 0.567962 0.641441 0.619064 0.641332 0.6775161992 0.723982 0.635607 0.857463 0.422982 0.254706 0.378906 0.412933 0.490603 0.737043 0.433684 0.513758 0.5386151993 0.596147 0.559985 0.6488 0.351554 0.179963 0.439426 0.793692 0.613996 0.500368 0.489134 0.46302 0.4735621994 0.359203 0.432001 0.441534 0.591409 0.51804 0.502538 0.303428 0.280603 0.306 0.343161 0.416323 0.5528431995 0.642515 0.556809 0.536112 0.70792 0.47719 0.518353 0.33113 0.429961 0.3878 0.505359 0.486976 0.3287851996 0.351237 0.384721 0.555003 0.410631 0.521852 0.213247 0.508115 0.565672 0.546895 0.306533 0.325427 0.2907541997 0.304529 0.367022 0.240624 0.485706 0.57347 0.520185 0.603952 0.448237 0.45294 0.517925 0.48582 0.5534331998 0.837716 0.522569 0.550902 -0.16711 -0.01944 0.219535 0.372073 0.374661 0.451798 0.504258 0.435467 0.373831999 0.269397 0.034533 0.205581 0.32664 0.31156 0.579121 0.508045 0.500822 0.42046 0.335533 0.253593 0.23126

Factor 1 (21.7%)

0

0.2

0.4

0.6

0.8

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Factor 2 (19.28%)

0

0.2

0.4

0.6

0.8

1

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Factor 3 (16.46%)

0

0.2

0.4

0.6

0.8

1

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Factor 4 (15.87%)

0

0.2

0.4

0.6

0.8

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Multiple Regression ModelsMultiple Regression Models

VARIABLESVARIABLES LAGLAG COEFFICIENTSCOEFFICIENTS RR22partialpartial R2

Solar RadiationSolar Radiation -2-2 0.24970.2497 90.65 %90.65 %

 

     

InterceptIntercept -0.6579-0.6579

January-March

-0.4

0

0.4

0.8

1.2

1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998

Ch

loro

ph

yll c

on

cen

trat

ion

(u

g/l)

Observed Values Predicted Values

45.22 %45.22 %

VARIABLESVARIABLES LAGLAG COEFFICIENTSCOEFFICIENTS RR22partialpartial R2

CladoceransCladocerans -1-1 -0.0655-0.0655 35.98 %35.98 % 80.17 %80.17 %

Total PhosphorusTotal Phosphorus -1-1 0.14420.1442 34.97 %34.97 %  

InterceptIntercept      

April-May

-0.4

0

0.4

0.8

1.2

1.6

1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998Ch

loro

ph

yll c

on

cen

trat

ion

(u

g/l)

Observed Values Predicted Values

Bayesian AnalysisBayesian Analysis

ConclusionsConclusions

• Phosphorus limiting element for primary productionPhosphorus limiting element for primary production

• Temporal fluctuations 40 % of the total variability Temporal fluctuations 40 % of the total variability

Spatial heterogeneity 10 % of the total variabilitySpatial heterogeneity 10 % of the total variability

Interactions of space with time 10 % of the total Interactions of space with time 10 % of the total variabilityvariability

• Basic regulatory factors of spring bloom dynamics:Basic regulatory factors of spring bloom dynamics: 11stst phase Solar radiation phase Solar radiation 22ndnd phase Epilimnion phosphorus stock phase Epilimnion phosphorus stock Zooplankton grazing pressure (Daphnia Zooplankton grazing pressure (Daphnia

populations) populations)

AcknowledgementsAcknowledgements

• METRO King County (database 1995-2001)METRO King County (database 1995-2001)

• A.W Mellon Foundation and Dr. Daniel E. A.W Mellon Foundation and Dr. Daniel E. Schindler, Department of Zoology, University of Schindler, Department of Zoology, University of Washington (database 1975-1999)Washington (database 1975-1999)