Cyanobacteria

Blue-green scum on the surface of the water is a sign that it may be dangerous to swim. Blooms have been spotted across much of Lake Winnipesaukee.

In the spring, Lake Kanasatka in Moultonborough received an uncommon treatment for cyanobacteria that cuts off the bacteria’s food source. This summer, its waters are crystal clear.

The number of advisories is expected to rise in coming days.

State regulators advise staying out of the water when a cyanobacteria warning is in effect, to protect from harmful toxins.

The main strategy for reducing harmful algae blooms is limiting the nutrients that can get into lakes and ponds, state regulators said.

The drones can detect cyanobacteria blooms faster, and with less hassle, than environmental officials going from lake to lake.

Excess nutrients, as well as changes in the environment, are boosting the potential for cyanobacteria blooms.

Lakefront homeowners play a large role in reducing nutrient runoff into New Hampshire lakes, which help cyanobacteria grow.

The bacteria can be harmful to humans and animals, so here are a few tips on what to look for if you’re looking to cool off in lakes or ponds in the state.

Warmer summers and changing weather patterns give the bacteria that cause these blooms a longer season to thrive.