Blue-Green Algae
In recent years, toxins produced by certain blue-green algae species have been found in Lake Champlain. Algae toxins present a potential hazard to swimmers and their pets, and could affect drinking water collected during bloom periods.
However, not all algae produce toxins, and even those species that can produce toxins do not do so in all instances. Lake Champlain’s algae blooms are most likely to occur in shallow bays in the northeastern portion of the lake. Deep, cold water locations with fewer nutrients, such as the Main Lake, are less likely to support blooms.
Nuisance algae blooms result from too much phosphorus pollution in the lake. Reducing pollution is the key to minimizing future blooms. The Lake Champlain Committee’s work helps the pubic better understand the risks associated with blue-green algae blooms.
LCC's Past and Ongoing Projects
- Raised awareness of increase in blue-green algae blooms and pushed for research and monitoring to understand causes.
- Established and run a volunteer monitoring program in cooperation with the University of Vermont, designed to determine when algae blooms appear to be producing toxins and to inform the public through relevent health agencies when toxic blooms occur.
- Produced a brochure to help distinguish blue-green algae (PDF, 450K) from other algae species and other floating phenomena in Lake Champlain.
- Conduct weekly surveys of public access points around the lake during the summer and report on algae bloom conditions.
Algae Monitoring Results Summary
Results from the Lake Champlain Committee's volunteer water monitoring program provide insight into the levels and locations of nutrient pollution. In 2008, significant algae blooms developed in Missisquoi Bay, in the northeast section of the lake. They were also observed in St. Albans Bay, which is a bit further south, and were noted sporadically throughout other parts of Lake Champlain.
In total, there were 21 "low alerts" and three "high alerts" issued during the 10 weeks of citizen monitoring, with an additional two low alerts resulting from samples taken during shoreline surveys. High alerts occur when there are dense algae scums, and toxins are above levels of concern. Low alerts occur when the density of potentially toxic species is high, but the actual level of toxins is below levels of concern.
Missisquoi Bay saw three high alerts and 12 low alerts at the four volunteer monitoring sites, St. Albans Bay saw four low alerts, and an additional five low alerts were issued in other parts of the lake.
Comparison with recent years
| year | low alerts | high alerts |
|---|---|---|
| 2008 | 21 | 3 |
| 2007 | 6 | 0 |
| 2006 | 48 | 3 |
| 2005 | 21 | 3 |
2009 Algae Conditions
| Sample Areas | July 13 | July 20 | July 27 | August 3 | August 10 | August 17 | August 24 | August 31 |
| Missisquoi Bay (5 sites) | No alerts | 2 High alerts at eastern sites | 2 Low alerts | 2 Low alerts | 1 Low alert, 1 High alert | 4 Low Alerts | 2 Low alerts | 1 Low alert |
| St. Albans Bay (1 site) | No alerts | No alerts | No alerts | Low alert | No alerts | Low Alert | No alerts | No alerts |
| Islands (4 sites) | No alerts | No alerts | No alerts | No alerts | No alerts | No alerts | No alerts | No alerts |
| Burlington area (2 sites) | No alerts | No alerts | No alerts | Low alert at Red Rocks | No alerts | Low alert at North Beach | Low alert at Red Rocks | No alerts |
| New York (4 sites) | No alerts | No alerts | No alerts | No alerts | No alerts | No alerts | No alerts | No alerts |
| South Lake (2 sites) | No alerts | No alerts | No alerts | No alerts | No alerts | No alerts | No alerts | No alerts |
