Scotland's lochs and reservoirs have increased in temperature over recent years sparking the risk of dangerous algae, according to new research.
A report published by Scotland’s Centre of Expertise for Waters (CREW) found that climate change has caused water to warm up by up to 1C per year between 2015 and 2019.
Over this period, 9% increased by more than that – some by up to 1.3°C per year. Some 97% of monitored Scottish lochs and reservoirs have increased in temperature.
This means if you are planning on going wild swimming this summer, you may have to rethink that decision.
That's because researchers warn that these changes increase the risk of harmful algal blooms developing, which could restrict their use for recreation and water supply, and as a safe habitat for wildlife.
One risk of warmer lochs is blue-green algae. It's a type of bacteria - called cyanobacteria - that is invisible to the naked eye.
This bacteria can multiply quickly in warm water and form a 'bloom' and produces chemicals that are highly toxic to humans, dogs and other animals - even if ingested in small quantities.
According to the NHS, these toxins can cause:
- Skin rashes,
- Nausea,
- Vomiting,
- Stomach pains,
- Fever,
- Headaches,
- Occasionally, more serious illness such as liver and brain damage.
You may be exposed during any activity where you may come into contact with the water, swallow water or breathe in water droplets for example swimming, sailing and boating, water skiing or even fishing.
This means any bodies of fresh water with visible algal blooms are a no go for wild swimmers.
These algal blooms are made up of the same blue blue-green algae which is highly toxic to dogs.
Blooms appear as a discolouration of the water (often a pea green colour) or as a visible scum layers or floating mats.
Blooms usually occur in the summer and early autumn but can occur at other times of the year.
If certain wind conditions are present, the film will often concentrate along the shoreline in areas where animals may drink or swim.
According to the study, it is expected that waters in the south and east of Scotland are expected to warm the most at first, but this climate-related impact will reach all parts of the country by 2040.
The report makes a number of recommendations to address these impacts in the immediate term, as well as further research to improve our understanding of climate impacts on the complex functioning of lochs and reservoirs.
Environment Minister Mairi McAllan said: “This important research provides yet more worrying evidence of the risks of harm from climate change on Scotland’s water environment.
“Scotland is renowned worldwide for the quality of our water.
"Research like this will be hugely valuable in informing the development of policy solutions and measures to mitigate and adapt to climate change, and also protect, restore and enhance these vital natural assets.”
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