Warming climate may speed algae spread

Blue-green algae growth is a spreading threat to major water bodies around the world.

Last summer, 32 blue-green algae warnings were issued for recreational lakes in Alberta because of health risks to people and animals.

However, one University of Calgary student assessed algae prevalence in small prairie lakes. As the climate grows warmer and drier, the risk could increase in shallow lakes, ponds and sloughs.

“There are questions as to whether the Prairies will be more and more dominated with blue green algae growth,” said graduate student Susan Anderson at the May 3 Bow River Basin Council science forum held in Calgary.

However, as temperatures in-crease, more evaporation is anticipated, which could make shallow water bodies saltier. The higher levels of sulfate could inhibit algae growth.

Algae is a problem when warm conditions promote rapid growth and eventual decomposition.

Products are available to get rid of it but must be used with care.

Blue-green algae can produce toxins that cause skin irritations and nausea and can poison livestock or pets. Algae removes oxygen from the water and can kill aquatic life, disrupting ecosystems.

Algae need warm water and light for photosynthesis. They also need the right ratio of phosphorus and nitrogen, as well as trace elements like molybdenum.

Most Alberta lakes have higher levels of sulfates and when these salts are present, fewer cells multiply and form algae.

Anderson sampled 25 lakes and ponds east of Calgary four times from June to September. Back in the lab, she measured pH, temperature, sulfate levels, turbidity, chlorophyll, molybdenum, nitrogen, phosphorus and other elements in water samples.

Algae was easy to find and had higher growth when nitrogen was limited. Higher growth was also noted where molybdenum was available.

Blue-green algae refers to the bacteria called cyanobacteria found in surface waters, including dugouts. The algae can be blue-green or greenish-brown and often smell musty or grassy.

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