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Whole Lake Experiments to Control Harmful Algal Blooms in Multi-Use

Watersheds

Presentation to the Middle Huron Partners

8 November 2006

U.S. EPA STAR Grant R830653-010• Develop management plan to control nuisance algal blooms

• Compartmentalize river; identify key regions

• Develop plans that look beyond P control alone

• Investigate N:P ratios

• Investigate internal nutrient loading

• Identify limiting factors for non-nuisance algae

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Study Site

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Courtesy: G.J. Cope, Nformation Design 2006

28°C lots of oxygen

26°C no oxygen

Ford Lake Dam

$

Potential dead fish

Hydro power

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Entering the Study Site

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InterannualInterannual Variation in Variation in Diatom Bloom Dynamics: Diatom Bloom Dynamics: roles of hydrology, nutrient limitation, roles of hydrology, nutrient limitation, sinking, and whole lake manipulationsinking, and whole lake manipulation

Julie FerrisJulie Ferris

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Why don’t diatoms normally persist Why don’t diatoms normally persist past May?past May?

SRSiSRSi DynamicsDynamics

SRSiSRSi (soluble reactive silica) is essential (soluble reactive silica) is essential for diatom growth, but not for most other for diatom growth, but not for most other species of algaespecies of algae

During a diatom bloom, During a diatom bloom, SRSiSRSi levels in the levels in the lake declinelake decline

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2004 was a good spring for diatoms; 2005 and 2006 were not so good.

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ExperimentsExperiments

Two TypesTwo TypesBioassay (P, Si, and P+Bioassay (P, Si, and P+SiSi additions)additions)Growth (no additions made)Growth (no additions made)

Response measured by changes in Response measured by changes in nutrient and chlorophyll concentrations nutrient and chlorophyll concentrations between start and end of experiments between start and end of experiments

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2005 Experiments2005 Experiments

9 Bioassay experiments (Feb9 Bioassay experiments (Feb to to May) May) 7 for Ford Lake7 for Ford Lake4 for Barton Pond4 for Barton Pond

13 Growth experiments (May13 Growth experiments (May to to Aug) Aug) for Ford Lakefor Ford Lake

ResultsResults

BioassaysBioassaysP addition P addition positive growth in all casespositive growth in all casesSi addition Si addition positive growth only oncepositive growth only once!!!!!! Lake Lake SRSiSRSi remained high in 2005remained high in 2005

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ResultsResults

Growth ExperimentsGrowth ExperimentsIncrease in Particulate (Diatom) Increase in Particulate (Diatom) SiSiin 12 out of 13 Experimentsin 12 out of 13 Experiments

ConclusionConclusion-- diatoms can grow in Ford diatoms can grow in Ford Lake water during the summerLake water during the summer

Lake FlushingLake Flushing

Could the lake flushing rate account Could the lake flushing rate account for the differences in the diatom for the differences in the diatom populations among years?populations among years?

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Mathematical ModelMathematical ModelTest idea that flushing rate controlled Test idea that flushing rate controlled differences in diatom populations differences in diatom populations among years. Model includes:among years. Model includes:

Diatom growth rateDiatom growth rateSi uptake rateSi uptake rateOutflowOutflowNO sinking, grazing, or parasitismNO sinking, grazing, or parasitism

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Mathematical ModelMathematical Model

Model works well from April to early Model works well from April to early MayMay-- then loss rates accelerate.then loss rates accelerate.

Grazing? Yes in experiments, but Grazing? Yes in experiments, but conditions may not be optimalconditions may not be optimalParasitism? Yes in experimentsParasitism? Yes in experimentsSinking? Not in experimentsSinking? Not in experiments

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HypothesisHypothesis

Diatoms will grow in the summer if:Diatoms will grow in the summer if:Outflow is low enoughOutflow is low enoughSinking is minimized (deeper lake Sinking is minimized (deeper lake mixing)mixing)

Hypotheses for Whole Lake Experiments

1. Ford Lake will not export P if deep water remains oxic.

2. Ford Lake will grow diatoms during summer if deep mixing can be achieved.

3. If diatoms consume lake nutrients (N and P), bluegreens will have less resource and will be less successful.

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December 2005-

Ypsilanti Charter Township Board of Trustees votes unanimously to endorse, and to confirm cooperation in proposed whole lake experiments.

We decided to try

And intend to try

in 2006

in 2007

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Experimental Plan for Summer 2006

Selective withdrawal of water from base of Ford Lake Dam

Q: How much flow is required to prevent anoxia?

Q: Can removal of cooler water destabilize the lake?

Experiment 2006-1: Calibration

Numerical model suggested that 300,000 cubic meters per day could reverse anoxia.

Plan: release 300,000 m3/d (123 CFS) from 22 to 30 June 2006.

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Experiment 2006-2: Calibration

Test whether a lower rate of discharge can produce beneficial effects with less loss of hydroelectric capacity.

Plan: release half as much water as in X2006-1 (ca. 65 CFS) from 14 to 21 July 2006.

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Experiment 2006-3: Calibration

Try to repeat X2006-1.

Plan: release 300,000 m3/d from 28 July to 4 August 2006. With shorter day lengths, nighttime mixing may be possible.

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ResultsResults

Cold, deoxygenated water was removed Cold, deoxygenated water was removed from the lake bottom. This resulted in:from the lake bottom. This resulted in:

DestratificationDestratificationDeeper lake mixingDeeper lake mixingSummer diatom bloomSummer diatom bloom

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AulacoseiraAulacoseira

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Microcystin Levels in Ford Lake August to September

330.20.200--3.93.9272720062006

880.40.400--12.812.8383820052005

# Dates # Dates >1nM>1nM

Median, Median, nMnM

Range, Range, nMnM

N N samplessamplesYearYear

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What about Belleville Lake?Did we just export the problem downstream?

Belleville Lake at dam

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10

20

30

40

50

60

70

80

90

Jun-03 Oct-03 Jan-04 Jun-04 Oct-04 Jan-05 Jun-05 Oct-05 Jan-06 Jun-06 Oct-06

ug/L

Chl

or P

C

Chl aPC

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How much water does it take to do the job?

- About 130 cubic feet per second.

How much is that?

Huron River Flow: Last 22 Years

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Table 1. Elemental composition of Ford Lake sediments reported as mean and range of concentration from three sites and depths from 0 to 8 cm below mud-water interface (n= 35 samples). Values are given as mg of element per kg of dry sediment, or ppm. Element MW Mean Min MaxCa 40.1 156740 143608 166131Si 28.1 152253 146642 161528Al 27.0 42047 39638 44343Fe 55.9 31325 27525 33406Mg 24.3 14252 13433 14837K 39.1 9510 8776 10039Ti 47.9 2397 2239 2512Na 23.0 1671 1571 1880P 31.0 1186 863 1500Mn 54.9 1002 939 1190 Ba 137.3 413 389 430 Zn 65.4 249 208 282 Sr 87.6 221 210 258 Cr 52.0 97 80 109 Zr 91.2 90 85 99 V 50.9 77 71 81

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Table 1. Elemental composition of Ford Lake sediments reported as mean and range of concentration from three sites and depths from 0 to 8 cm below mud-water interface (n= 35 samples). Values are given as mg of element per kg of dry sediment, or ppm. Element MW Mean Min MaxV 50.9 77 71 81 Rb 85.5 73 67 77 Pb 207.2 57 41 75 Cu 63.5 44 36 52 Ce 132.9 43 37 49 Ni 58.7 29 24 33 La 138.9 23 18 27