What do warmer temperatures mean for the health of our lakes?

Author: Arunemathi Shanmugam, University of Waterloo

This July was the warmest on record and we expect to continue to see record-breaking weather in the near future. Warmer air temperatures will cause a variety of changes, including changing ice-covered periods, areas that experience ice cover, reducing snow cover, decreasing snowfall, and increasing water temperatures1. These changes are obviously bad news for our friends who enjoy snowmobiling and ice fishing, but what do they mean for the health of our lakes?

Climate change is expected to decrease dissolved oxygen (DO) concentrations in Ontario lakes. DO comes mainly from the atmosphere and supports aquatic animals2. In particular, increased water temperatures caused by climate change will likely have a significant impact on DO concentrations in the deepest parts of our lakes. Differences in shallow and deep water DO are influenced by water temperature. Cold water holds more DO than warm water because colder water temperatures increase the solubility of oxygen in water3. DO will decrease in shallow waters as water temperatures rise, due to rising air temperatures and reduced wind speeds4. DO concentrations throughout a lake are affected by the distinct layers of water that form due to temperature differences5. Water near the lake’s surface is warmed by the sun and becomes less dense than the colder water underneath it6. The differences in temperature between surface waters and deeper waters produce layers of water of different densities that do not easily mix7. So, this layering of water prevents water from circulating throughout the lake, so deep water DO is not readily replenished by atmospheric oxygen like the shallower layers.

Changes in DO concentrations can make it more difficult for lakes to support aquatic life. Most aquatic animals have a preferred range of water temperature and DO concentration. For instance, Lake Trout (Salvelinus namaycush) prefer cold water habitats that are well oxygenated8. Decreases in DO in deep water can force deep-water fish up into warmer waters, where their survival is jeopardized9. Overtime these fish could die as they struggle to compete with fish that are more tolerant to low oxygen habitats10.

Loss of deep water DO also degrades water quality11. Really low levels of DO can cause chemical reactions that release nutrients from lake sediments. The release of nutrients, like phosphorous, can stimulate the growth of algae, which can produce harmful algal blooms12. These algal blooms can produce dangerous toxins that are harmful to humans and animals13.

Due to the importance of DO for healthy lake ecosystems, it is often used to measure the health of lakes and streams. The RLCA has purchased a DO data logger to monitor DO levels in our lakes. DO monitoring will help give us an early warning sign if climate change is harming our lake ecosystems. The RCLA is collaborating with the University of Waterloo this fall in a study looking at comparing DO concentrations across lakes to better understand if the deep locations currently monitored by the Lake Partner Program is sufficient as our only monitoring location.

1 United States Environmental Protection Agency, “Climate Change Indicators: Snow and Ice”, July 26, 2023, https://www.epa.gov/climate-indicators/snow-ice

2 Water Science School, “Dissolved Oxygen and Water,” last modified June 5, 2018, https://www.usgs.gov/special-topics/water-science-school/science/dissolved-oxygen-and-water#overview

3 United States Environmental Protection Agency, “Dissolved Oxygen”, May 18, 2023, https://www.epa.gov/caddis-vol2/dissolved-oxygen

4 Stephen F. Jane et al. “Widespread Deoxygenation of Temperate Lakes,” Nature 594 (2021): 66-70, doi: 10.1038/s41586-021-03550-y.

5 Paul Fafard, “How and Why Lakes Stratify and Turn Over: We explain the science behind the phenomena,” International Institute for Sustainable Development, May 16, 2018, https://www.iisd.org/ela/blog/commentary/lakes-stratify-turn-explain-science-behind-phenomena/

6 Ibid.

7 Ibid.

8 We Fish Canada, “Fish Species,” accessed August 11, 2023, https://www.wefishcanada.ca/fresh-water-fish-species/.

9 Emily Chung et al. “Bad news for fishing: Climate change is sucking the oxygen out of lakes, study suggests,” CBC News, June 10, 2021. https://www.cbc.ca/news/science/oxygen-climate-lakes-1.6059334.

10 Ibid.

11 Stephen F. Jane et al. “Widespread Deoxygenation of Temperate Lakes,” Nature 594 (2021): 66-70, doi: 10.1038/s41586-021-03550-y.

12 Ibid.

13 Ibid.

CLEAN, DRAIN and DRY Your Boat

Motors, boats, and Ontario’s ecosystems can be ruined by zebra mussels and other aquatic invasive species. Take a few simple steps to preserve our lakes and fisheries: CLEAN off any plants or debris, DRAIN bilges and ballast water, and DRY any wet areas of your boat.

Don’t Spread Invasive Species

Moving boats from one lake to another can spread invasive plant and animal species that harm our lake ecosystems and reduce our enjoyment of recreational activities. For example, the thick mats created by invasive plant species, such as Eurasian Water-Milfoil and Starry Stonewort, can ruin swimming, boating, and fishing. You can help protect our lakes from the spread of invasive species by encouraging your friends and family to clean, drain, and dry their boats before moving them to another lake.

Learn More:  General Info  |  Eurasian Water-Milfoil  |  Starry Stonewort

Rock Our World – Fundraising Dance

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Within the various uses of the word today, “nature” often refers to geology and wildlife. Nature can refer to the general realm of living plants and animals, and in some cases to the processes associated with inanimate objects – the way that particular types of things exist and change of their own accord, such as the weather and geology of the Earth.

This more traditional concept of natural things which can still be found today implies a distinction between the natural and the artificial, with the artificial being understood as that which has been brought into being by a human consciousness or a human mind. Depending on the particular context, the term “natural” might also be distinguished from the unnatural or the supernatural.

The interior remains active, with a thick layer of plastic mantle and an iron-filled core that generates a magnetic field. This iron core is composed of a solid inner phase, and a fluid outer phase. It is the rotation of the outer, fluid iron core that generates an electric current through dynamo action, which in turn generates a strong magnetic field.

Private Hazard Buoy Initiative

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Within the various uses of the word today, “nature” often refers to geology and wildlife. Nature can refer to the general realm of living plants and animals, and in some cases to the processes associated with inanimate objects – the way that particular types of things exist and change of their own accord, such as the weather and geology of the Earth.

This more traditional concept of natural things which can still be found today implies a distinction between the natural and the artificial, with the artificial being understood as that which has been brought into being by a human consciousness or a human mind. Depending on the particular context, the term “natural” might also be distinguished from the unnatural or the supernatural.

The interior remains active, with a thick layer of plastic mantle and an iron-filled core that generates a magnetic field. This iron core is composed of a solid inner phase, and a fluid outer phase. It is the rotation of the outer, fluid iron core that generates an electric current through dynamo action, which in turn generates a strong magnetic field.

Ladies of the lake

It was on a beautiful sunny Sunday afternoon of the Victoria Day Weekend that 24 ladies gathered at Judy Cole’s for coffee, sweets and lots of discussion on common interests and activities we would like to do together.

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Within the various uses of the word today, “nature” often refers to geology and wildlife. Nature can refer to the general realm of living plants and animals, and in some cases to the processes associated with inanimate objects – the way that particular types of things exist and change of their own accord, such as the weather and geology of the Earth.

This more traditional concept of natural things which can still be found today implies a distinction between the natural and the artificial, with the artificial being understood as that which has been brought into being by a human consciousness or a human mind. Depending on the particular context, the term “natural” might also be distinguished from the unnatural or the supernatural.

The interior remains active, with a thick layer of plastic mantle and an iron-filled core that generates a magnetic field. This iron core is composed of a solid inner phase, and a fluid outer phase. It is the rotation of the outer, fluid iron core that generates an electric current through dynamo action, which in turn generates a strong magnetic field.