Hot Weather Increases Toxic Blue Green Algae Threats in Farm Water Sources
Rising summer temperatures are increasing the risk of toxic cyanobacteria in agricultural water sources. Cyanobacteria, commonly called blue green algae, can produce harmful toxins that affect livestock, wildlife, and humans. Experts warn that producers should stay alert during hot and dry conditions.
According to North Dakota State University Extension, warm temperatures speed up cyanobacteria growth. These organisms thrive when water contains high levels of nutrients such as nitrogen and phosphorus. These nutrients often enter ponds and dugouts from fertilizers and manure applied to fields. Improper timing or excess application increases the chance of runoff into surface water.
“The hot, dry conditions projected for July are ideal for the growth of cyanobacteria,” said Miranda Meehan, NDSU Extension livestock environmental stewardship specialist.
Cyanobacteria commonly appear in stagnant ponds with low water movement. They form visible scum on the surface that may look green, red, or yellow. When the bloom dies, it can turn blue and collect near the edges of water bodies.
The toxins produced by cyanobacteria can cause serious health problems. Animals may show signs of poisoning within minutes or hours after drinking contaminated water. Symptoms include weakness, muscle tremors, breathing issues, and even death. In some cases, livestock die suddenly before any warning signs are noticed.
Experts advise checking ponds regularly, especially during hot weather. Producers should also look for dead wildlife near water sources as an early warning sign. If poisoning is suspected, veterinarians should be contacted for proper examination.
“A veterinarian can determine which samples would be appropriate for each situation,” said Dr. Jake Galbreath, NDSU Extension veterinarian and livestock stewardship specialist.
Water testing plays an important role in managing risk. Samples should be collected carefully, using gloves, and sent to certified laboratories for analysis. Both microscopic algae checks and toxin testing can confirm contamination.
Prevention is key for managing cyanobacteria. Practices such as reducing nutrient runoff, maintaining buffer strips, and controlling water access for livestock can help. Using alternative water sources during high-risk periods and drawing water from deeper areas may also reduce exposure.
“Unless steps are taken to reduce the nutrient load and minimize the potential for nutrients to enter the water body, the risk for cyanobacterial blooms will continue,” said Laxmi Prasad, NDSU Extension water engineer.
Proper nutrient management and erosion control are essential to limit long-term risks. By adopting safe practices, farmers can protect livestock and maintain healthy water systems.
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