Beneficial Use Impairment #8
BUI #8 - Eutrophication and undesirable algae
Status - Impaired
One of the main environmental issues with the Bay has always been the amount of nutrients entering it, particularly phosphorus.
Phosphorus is a naturally-occurring element, essential to all life. In just the right amount, it’s a beneficial, life-giving nutrient for rivers, lakes, bays, and streams. On the other hand, too much phosphorus plays havoc with nature.
ln aquatic ecosystems like the Bay of Quinte, the ability of phosphorus to promote rapid growth causes problems. It takes only 1 lb. of phosphorus to grow 500 lbs of algae.
This nutrient-enrichment process is known as eutrophication, and it’s a classic example of too much of a good thing.
The BQRAP has reduced the amount of phosphorus entering the Bay from multiple sources, both rural and urban, such as sewage treatment plants, stormwater run-off, and agricultural land practices.
With the reduction in phosphorus levels, water clarity has improved due to reduced algae. Making the Bay one of the most picturesque spots in Lake Ontario.
Underwater plants have re-grown providing fish with habitat, helping to increase the varieties of fish in the Bay.
Despite the reductions in phosphorus inputs, the current phosphorus levels are still a major concern.
A Phosphorus Management Strategy is being developed to outline best practices for dealing with phosphorus issues in the future.
Criteria and supporting evidence
1. A 25
percent reduction in total phosphorus (TP) in the upper Bay of Quinte. Impaired
the average concentration of TP from 40 μg /L to 30 μg /L in the upper Bay of
Quinte for the period of May to October. Note:
Modelling recommended new targets.
2. A 40
percent reduction in algae in the Upper Bay of Quinte. Impaired
a change in total phytoplankton biomass such that the average pre-1990 density
of 7.0-8.0 g/m3 to is reduced to 4.0-5.0 g/m3 for the period of May to October. Note: Modelling recommended new targets
results of DFO/MNR assessment of impact
of current & proposed targets on food chain