An Investigation on the Effects of Climate Change

On Algal Blooms in Lake Champlain

Patricia Brousseau, Lauren Chicote, John Keyes, Jenna Mandelbaum,

Christopher Smith

Problem

• Environmental Stressors induced by climate change– Temperature– Runoff Intensity– Lake Freeze-over

• Change in internal phosphorus loading• Change in species composition of algae

Why?

• Clean Water Act• Primary Productivity• Nutrient Cycling

Objectives

• Asses risk of algal blooms• Identify factors influencing algal blooms• Predict changes in algae species composition,

phosphorus dynamics and bloom periods• Formulate recommendations

• Phosphorus Sources and Loading• Climate Change• Lake Freeze-over• Stratification and Mixing• Internal Phosphorus• Algal Blooms• Conclusions• Recommendations

Non-Point Source Phosphorus Loading• Main sources of Phosphorus are Agricultural and Developed Land•Typically more P loading from developed acreage than agricultural land

Source: Lake Champlain Basin Program 2005

Detailed Sources of Phosphorus• Relative amount

of Phosphorus loading by source.

• Animal Feeding lots are replaced by Dairy Farms in Lake Champlain Basin

Source: Lake Champlain Basin Program 2005

Agricultural Land Creates Impairment of Aquatic Systems

• Pesticides, Herbicides, and Fertilizer Use• Nutrient Loading

– Nitrogen– Phosphorus

• Sedimentation and Erosion• Natural Ecosystem Land Use Change• Increase in Demand for Water

Agricultural Land Use Increase• Global agricultural land use increase of

18%.

• 2.7-fold increase in phosphorus-driven Eutrophication globally.

• Longer Growing Season Source: Tilman et. al (2001)

Winter Precipitation

(Northeast Climate Impacts Assessment 2007)

Winter Snow Cover Days

(Northeast Climate Impacts Assessment 2007)

Flood Pulse Concept

(Wantzen et al. 2008)

Droughts

(Hayhoe et al. 2006)

Lake Freeze-Over

• Climate change increase air temps. increase water temps. less free-over events

Graph courtesy of Mary Watzin, ENSC 201 course

Changes in Lake Dynamics • Changes in lake

ice effect stratification/ turnover effect internal P loading

Internal Loading

Factors that Influence Internal Loading

St. Albans Bay: Case study exampleBy: Eric Smeltzer Vermont Department of Environmental Conservation Water Quality Division: 2003

Major Findings 1.Temperature2.Wind Velocities- physical re-suspension3.Bivalves

Temperature

Mineralization

Direct effect on decomposition and release

Indirectly lowers redox potential

Release of reductant soluble P

Inner Bay Regions

Kleeberg 1997 & Jensen 1992

Stratification and Climate change ???

1. An increase in surface water temperatures

2. Increase in temperature in both surface and hypolimnetic waters by same order of magnitude

Stratified Portions of the Lake during summer stratification

Pettersson 2001

Stratified Regions of the Lake; end of Summer P fluxA result of P accumulation in the hypolimnion during summer stratification due to thermocline. 1. Low pH2. Low redox3. Low Dissolved Oxygen

All factors influenced bya.Increase temperature in and biological activity in sediments

Komatsu et al 2007

Its all about the total P in the sediments!

Cyanobacteria

Microcystis aeroginosaSource: Lake Erie Center, University of Toledo

Hazards

• In 2000, three dogs died from drinking lakewater contaminated with cyanobacteria, probably Anabaena.

• Three toxic genera found in Lake Champlain: Microcystis, Anabaena, Aphanizomenon

• Cyanobacteria favored in warming climate.

Source: Jöhnk et al. (2007) Simulation of phytoplankton populations under three sets of physical parameters.

Source: Jöhnk et al. (2007) Schematic of model effects relating environmental parameters to phytoplankton populations.

Source: De Senerpont et al. (2007) Laboratory populations of phytoplankton under three different temperature regimes.

Conclusions• Phosphorus

– Inner Bay Regions: Increase in Water Temp: Increase in Phosphorus Released from Sediments

– Stratified Areas: Longer Periods of Stratification, more release of Phosphorus

– Higher Temps = Larger Epilimnetic Zone. Increasing mineralization, increasing soluble and liable phosphorus

– Earlier ice-out, earlier spring run off = Earlier Phosphorus availability

– Less Freeze over events, increased winter turbidity. Limits Phosphorus binding to sediments in winter months

Conclusions• Algae

– Higher Phosphorus availability from:• Agriculture and Other Non-Point Sources• Higher concentration of liable Phosphorus

– Earlier and Longer Growth Periods• Higher Annual Temperatures• Earlier Ice-out, Spring Run-off and Turnover, Later Fall

Turnover• Longer Growing Season

– Change in Species Composition

Recommendations• Promote BMP in Agriculture• Construct Wetlands in Specific Problem Areas in Lake

Champlain• Increase Riparian Buffers in Impaired Waterways• Construct Floating Living Machines as designed by

John Todd to uptake Phosphorus• Create Constant Vertical Turbidity