Darren Brandt Advanced Eco-Solutions Inc.

Lakes are complex systems. Assessments tend to drastically oversimplify lake dynamics.

One cannot examine one aspect of a lake and make determinations regarding it’s condition or future conditions. Chemistry, biology, physical environment all

interact with each other Even within these silos of investigation there

are dozens of complex interactions, many of which are poorly understood in the limnological science.

Even systems that have been intensely monitored and studied for years it’s difficult to predict future conditions.

Yes, we can determine average conditions, and we can simplify our analysis to improve our predictions.

Lake dynamics are not dissimilar to weather forecasting. Climate values are not useful for forecasting, neither are average Chl a or water chemistry values particularly useful in predicting ecosystem responses.

Water Chemistry responses can be subtle or un-detectable

Biological Responses are not frequently measured and harder to predict.

Response to change are rarely linear.

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0 5 10 15 20 25 30 35

Nitr

ogen

(mg/

L)

Time (Hours after application)

Ammonia

NO2+N03

Total Nitrogen

0.00%

5.00%

10.00%

15.00%

20.00%

25.00%

30.00%

2005 2006 2007 2008 2009 2010 2011

% o

f Phy

topl

ankt

on B

iovo

lum

e

Microcystis sp. Anabaena sp.

1820

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1860

1880

1900

1920

1940

1960

1980

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2020

0 2 4 6 8 10Sediment Accumulation Rate

(g/m2/year)

Sed. accumulation

Whiskey Point

Bottle Bay

Contest Point

One cannot expect useful model outputs if: there is a scarcity of data; Complex systems are represented by summary

values (chl a) No consideration is given to synergistic effects Models are developed based on it’s “experience”, or

historical data. Once the system is significantly modified you are outside the range of experience of the model.

These interactions can mask or buffer the system from change.

The change of the biotic and abiotic environment can and will ripple through the system.

The ripples can magnify and have an increasingly large impact on the function of the system

Increased primary productivity Increase in inedible phytoplankton Increase in duration and severity of blue-green

algae blooms. Increased internal cycling or loading of

nutrients (feed back loop increasing the impact of proposed actions)

Decrease in carbon flow into the food web resulting in decreased fish production.

Insufficient data and understanding on biology of the system and synergistics effects.

WQ standards and meeting WQ standards does not necessarily protect the ecosystem. Need to address cumulative effects.

Recirculating Fish Lake out flow will result in increased nutrient concentrations within the lake (Aquarium effect).

Loss of wetlands, severe change in hydrology, increase in metals, increase in nutrient concentration cannot be mitigated.

Fish die off likely to occur within a decade of implementation.