Harmful Algal Blooms and Safety

As the summer months approach and temperatures rise, harmful algal blooms (HABs) can occur in bodies of water, as a growing symptom of climate change. For concessioners operating in and around both fresh and salt water, this can be a concern. HABs are occurring in more locations and more often than ever before. These toxic blooms pose threats to humans and animals. HABs are not limited to bodies of saltwater; freshwater lakes, ponds, and rivers are also affected.

Causes

Some level of algae growth is healthy for an ecosystem; however, large HABs can produce dangerous cyanotoxins under certain conditions like low water levels; a high level of carbon, fertilizer, and agricultural runoff; and warmer seasons. HABs are more likely to occur in the summer and fall when temperatures are high, but they can occur any time of year. Changes in local ecology (e.g., biodiversity, urban development, invasive species, etc.) can trigger a HAB, too. Nutrient levels in water change regularly but large shifts of nitrogen and phosphorus from fertilizer, sewage, or run-off can cause HABs to bloom.

Effects and Safety

In Alaska, sea otters are experiencing high levels of algal toxics, likely from consuming shellfish that reside in and around HABs. The effects are not limited to animals; humans who come in contact with the toxins in HABs can experience skin irritation, shortness of breath, and even liver and kidney damage.For horses, mules, and other animals, the consumption or aspiration of the toxins and cyanobacteria in HABs can be fatal. Ensure livestock do not enter HAB water, drink it, or graze near it. If an animal does come in contact with a suspected or known HAB, rinse them off immediately with fresh, clean water from a hose or outdoor spigot.