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 Inner Bay Regions Deeper stratified portions of the lake Regions During summer stratification End of the summer season Season

Factors that Influence Internal Loading TemperatureDissolved Oxygen / Redox Potential – Fe reductionExtent of StratificationBivalvesResuspension

St. Albans Bay: Case study example By: Eric Smeltzer Vermont Department of Environmental Conservation Water Quality Division: 2003 Major Findings 1.Temperature 2.Wind Velocities- physical re- suspension 3.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 bysame order of magnitude

Stratified Portions of the Lake during summer stratification Pettersson 2001

Stratified Regions of the Lake; end of Summer P flux A result of P accumulation in the hypolimnion during summer stratification due to thermocline. 1. Low pH 2. Low redox 3. Low Dissolved Oxygen All factors influenced by a.Increase temperature in and biological activity in sediments Komatsu et al 2007

Its all about the total P in the sediments!

Cyanobacteria Microcystis aeroginosa Source: 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