Kensington North Watersheds Association

2012 News

Anoxia Monitoring Group Formed

(2012-08-31) A group of 11 local residents has been set up to spot for anoxic events in the Kensington North area. Anoxic events occur in the estuaries (where the fresh water and salt water meet) on PEI, especially along our north shore, where the tidal range is relatively low and less flushing occurs. Anoxia is caused by an algae known as sea lettuce, or Ulva. During the summer months, sea lettuce grows rapidly in our warm, nutrient rich waters. As it becomes more and more populous, it uses up more and more of the available oxygen in the water. If it passes a critical point and depletes too much oxygen, the algae dies. The water goes from an aerobic environment, one that thrives on oxygen, to an anaerobic environment, where microbes flourish without oxygen. In the anaerobic waters, fish, shellfish, even normal sea weed, cannot survive for long. The anaerobic bacteria turn the water milky green, or even white. The decomposing sea lettuce emits a very smelly mixture of methane and hydrogen sulphide. It is extremely harmful for our estuaries, which on a per acre basis, can be our richest ecosystems. It is very unpleasant for local residents, who must endure the contaminated banks and water, and extremely unpleasant odours.

The source of anoxic events is nutrients in the water that create the unnatural, huge blooms of sea lettuce. The nutrients are in the form of nitrates that can be traced to chemical fertilizer and manure used in agriculture, plus septic systems and industry. The Kensington North Watersheds has a committee of farmers, residents, and developers who are working on the difficult task of creating a community based plan to reduce nitrates in groundwater and surface water. The plan is being worked on now, and will hopefully be ready sometime this winter.

The Anoxia Monitoring Group was formed because it is believed that many anoxic events occur without being recorded. The Anoxia Monitors receive information to help them identify anoxia, and then report anoxic events as they occur. By keeping a good record of the number and location of anoxic events, our community and our governments become more aware of the frequency and the seriousness of the problem, and hopefully hasten the implementation of measures required to reduce the impact of nitrates and anoxic events.

Click here for the latest map.

  Back to Top