Algae & Ticks Still Present in Autumn

The fall foliage is almost at its peak and prime hiking season is upon us. Even with the cooler temperatures, be aware of tick activity and possible cyanobacteria blooms as you explore the mountains and lakes.


For current tick activity in New England region, click here.

Mapping ticks - interactive map


Is Algae Normal in Lakes?

The first and maybe most important thing to note is that this is a completely normal occurrence. As nutrients and sunlight become more readily available in the water, these green algae begin to thrive, simultaneously providing food and shelter for a myriad of other organisms within the lake. These green, cloud-like masses are really just colonies of countless, thin strands of single-celled green algae. They are photosynthetic, meaning they use sunlight to break down carbon dioxide into oxygen and carbohydrates for other organisms within the lake, a very vital process within the water.

The growth rate of algae can be increased by environmental factors such as an early ice out or an excess input of nutrients. Additionally, it is not uncommon to see the location of this algae growth vary from year to year depending on which areas contain the most nutrients (phosphorus in particular) at that point in time. A large congregation of these algae can be irritating to lake-goers, as it may get in the way of recreation such as swimming and boating.

Can Algae be Harmful to Humans and Other Animals?

Although these filamentous green algae are not harmful to humans, there are some types of photosynthetic organisms which can pose potential health threats to humans and other animals. If the amount of nutrients, sunlight, and temperature are just right for these cyanobacteria, to thrive, they can form large blooms and are sometimes capable of producing harmful toxins. A cyanobacteria bloom can be identified by a layer of green or bluish algae over the lake, typically with an unpleasant smell.

You can follow this link to read more about cyanobacteria:

If you have questions or suspect a cyanobacteria bloom anywhere on the Squam Lakes, contact the NH DES Cyanobacteria Hotline (603) 848-8094