BUI #8 - Eutrophication and undesirable algae

Status – Redesignation process underway

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.

Video: Excess algae and phosphorus in the Bay of Quinte.

Criteria and supporting evidence

1. Target: Demonstrate a 25 percent reduction in total phosphorus (TP) in the upper Bay of Quinte.

Measure: Reduce 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.

THE CRITERION FOR PHOSPHORUS REDUCTION IN THE UPPER REACHES OF THE BAY OF QUINTE HAS BEEN MET.

2. Target: Associated with the Bay of Quinte RAP phosphorus reduction targets for the Upper Bay of Quinte, demonstrate a reduction in chlorophyll a levels in the upper Bay.

Measure: Reduce the chlorophyll a concentrations so that they are about 12ug/Lin the upper Bay for the growing season with out the presence of zebra mussels (with zebra mussels, a further 2 – 3 ug/L chlorophyll a reduction should be anticipated).

THE CRITERION FOR THE REDUCTION OF CHLOROPHYLL-A CONCENTRATIONS HAS BEEN MET.

3. Target: Demonstrate a 40 percent reduction in algae biomass in the Upper Bay of Quinte.

Measure: Reduce the total phytoplankton biomass from the average pre-1990 density of 7.0-8.0 g/m3 to 4.0-5.0 g/m3 for the May to October time period.

THE CRITERION FOR THE REDUCTION OF TOTAL PHYTOPLANKTON BIOMASS HAS BEEN MET.