Climate change is all around us and certainly in the news with the Climate Change talks in Paris. Climate change is arguably the biggest and most challenging threat to the Great lakes.
Most of the last century’s warmest years in the region all occurred in the last decade. (Read here to understand weather like El Nino vs. climate) The long term climate trend is showing that the region, like the world is heating up more rapidly then anytime in history despite recent short-term cold winter variations.
Water temperatures, water levels and water quality are linked
With this warming trend comes a variety of other effects: warmer water and air temperatures, earlier springs and later falls, less rain and snowfall, more protracted drought-like conditions, flashier storms, longer ice-free periods, and more evaporation and lower water levels.
Another effect that scientists are studying on northern lakes is longer stratification periods…
What is stratification?
Northern lakes have a kind of circulation from high to low depths that is related to winter freezing and heating of the lake. When the top layer of the lake is almost frozen, this layer sinks down. This sinking layer brings oxygen to lower depths and pushes nutrients up (*Cheryl Katz, Yale.edu). As the Lake heats up, the surface breaks into different layers that prevent the oxygen from intermingling into the deeper and cool depths below. This layering from the heating of the water is called stratification. As this process intensifies, it brings these risks:
- Risk to ecosystems: A longer stratification period due to longer summers and less cold winter temperatures, creates a bigger and longer low oxygen area of the lake that is unfit for many living things.
- Risk to water quality: It also increases conditions in which cyanobacteria can thrive, which can lead to toxic harmful algae blooms.
That means that your drinking water is also at risk. In August 2014, half a million Toledo residents lost their drinking water because of toxins in their water system from blue-green algae. Lake Erie experienced its largest ever toxic algae bloom this year which fortunately was pushed off shore away from their municipal water system intakes.
At Georgian Bay Forever, we are working on projects that help monitor and standardize water quality measures, and helping to support research into the causes of algal blooms in order to effectively reduce risk in the future.
Part 2, coming soon, will examine how water levels effect water quality.
Sources used in this post:
*Katz, Cheryl. “On Thin Ice: Big Northern Lakes Are Being Rapidly Transformed.” Yale Environment360. Retrieved December 1st at https://e360.yale.edu/feature/on_thin_ice_big_northern_lakes_are_being_rapidly_transformed/2933/
In October 2015, GBF’s David Sweetnam met University of Toronto Associate Professor Maria Dittrich in Honey Harbour to help her research measuring the make-up of the sediment, and its capacity to release Phosphorous into the water.
It’s important research as freshwater with high Phosphorous is linked with an increased risk in toxic algal blooms.
We asked Professor Dittrich some questions about her research, and have included extra information marked GBF to explain some of the details.
How does your research support protecting and enhancing the waters of Georgian Bay?Professor Dittrich:
Phosphorus is the typical limiting nutrient for primary production or algae growth in freshwater ecosystems, where high Phosphorus inputs are linked with an increased risk of algal blooms dominated by potentially harmful cyanobacteria (CHABs).
We are using field and modelling studies to predict sediment Phosphorus mobilization and its impact on water quality and the risk of CHABs, based on robust measures and a modelling framework that we have successfully developed and applied elsewhere. Read More