Cyanobacteria Blooms Persist Into Fall On N.H. Lakes and Ponds

Nov 1, 2019

State beach monitors say they're still observing cyanobacteria blooms on New Hampshire's lakes and ponds, even this late in the year.

Blooms have been seen recently on shorelines in on Country Pond Newton and on Webster Lake Franklin. They appear as green or blue streaks, flecks and pond scum, caused by excess nutrients in the water.

Cyanobacteria can contain toxins that can sicken or harm humans and pets on contact and can lead to serious chronic conditions.

State beach program coordinator Amanda McQuaid says it's not unusual to see cyanobacteria blooms this late in the year – especially after periods of rain and mild temperatures.

“As the lakes begin to turnover this time of year… there may be excess nutrients available in the water column,” McQuaid says in an email.

Over the summer, she says the state at least tied its record for the most cyanobacteria blooms observed. At least 34 were recorded.