September 11, 2018
NHDES issues Cyanobacteria Advisory for Winter Harbor
On August 30th, the NH Department of Environmental Services (NHDES) issued a cyanobacteria advisory for Winter Harbor, Lake Winnipesaukee. A possible toxin producing cyanobacteria called Gloeotrichia was spotted along the shoreline at the southern end of Winter Harbor near Carry Beach.
On September 5th, the bloom was reported to be 10x worse, but concentrated more along the eastern shore near White Gate Road. The bloom was identified and reported by one of the Lake Winnipesaukee Association’s volunteer water quality monitors, who regularly samples several sites in Winter Harbor and is trained in cyanobacteria monitoring. This proved fortunate in being able to quickly notify the NHDES and have the advisory issued.
Additional reports of algae and cyanobacteria in other areas of Winter Harbor were reported to the Lake Winnipesaukee Association this past weekend (9/8/18).
What is cyanobacteria and should you be concerned?
Cyanobacteria (often referred to as blue-green algae due to the bluish pigment, phytocyanin, that they contain) are photosynthetic bacteria (able to produce their own food) that have been in existence for over 2.5 billion years, are a natural component of New Hampshire waterbodies, and are important organisms for the health and growth of many plants.
However, certain cyanobacteria produce toxins that can affect the nervous system, liver, or endocrine system if ingested in large enough quantity. The Gloeotrichia bloom in Winter Harbor may contain microcystins, which are a liver toxin. Because it is unknown at the time of a bloom, whether or not it is toxic, the NHDES issues an advisory to people to avoid wading or swimming in, or drinking of the infected waterbody. Pets and livestock should be kept out of the water as well.
What can be done to deter blooms?
There is a direct relationship between increased levels of nutrients (phosphorus) in the lake and aquatic plant growth, algal growth, and cyanobacteria abundance. The only way to decrease the likelihood of a cyanobacteria bloom is through continued watershed management practices that reduce nutrients to the water. For the past seven years, the Lake Winnipesaukee Association (LWA) has led the effort to develop a lake-wide watershed management plan for Winnipesaukee. To date, over 500 sites have been identified where nutrient loading could be reduced, and another 200 recommended actions to improve water quality through education and outreach, municipal regulations and ordinances, monitoring, wastewater management, and land conservation.
The LWA works with the UNH Lakes Lay Monitoring Program to oversee the water quality monitoring program on Winnipesaukee. One of the Association’s goals is to expand the monitoring program to include cyanobacteria monitoring throughout the lake. Another important goal is to begin fixing the 500 sites that are contributing pollutants to the lake.
You can help in this effort. Although shorefront property owners are the first line of defense against nutrient loading to the lake, all property owners play a role in keeping the lake clean. Stabilize soil with native plants to avoid erosion. Keep the natural vegetation and buffer along the shoreline. Do not use fertilizers or pesticides on your property. Never rake leaves or dump sand into the lake. Reduce your lawn area. All of these practices will help keep nutrients out of the lake.
If you see an algal bloom or water quality issue, please contact the Lake Winnipesaukee Association at 603-581-6632 or
mail@winnipesaukee.org.