BUI #13 - Degradation of phytoplankton and zooplankton populations

Status – Final report in editing phase

Phytoplankton and zooplankton are the microscopic plants and animals that are at the base of the food web.

In the Bay of Quinte, phytoplankton and zooplankton species composition has changed over the years, because of reductions in phosphorus inputs and the introduction of invasive species. The food web has adapted and diversified to compensate for these changes.

Currently, the RAP team is developing a Phosphorus Management Strategy. Studies are being conducted to evaluate how varying reductions in phosphorus levels, recommended in the strategy, will affect the phyto and zooplankton populations in the Bay.

Criteria and Supporting Evidence

1. Associated with the Bay of Quinte RAP phosphorus reduction targets for the Upper Bay of Quinte, demonstrate that chlorophyll a concentrations are about 12 μg/L in the Upper Bay of Quinte without the presence of zebra mussels (with zebra mussel, a further 2-3 μg/L chlorophyll a reduction should be anticipated). Impaired

2. Demonstrate a positive change in phytoplankton species composition with a decrease in nuisance and eutrophic indicator species (e.g., microcystis, anabaena). Impaired

3. Measure a trend toward a more diverse zooplankton community shown as a range of mean individual sizes between 0.45 and 0.5 mm for cladocerans. Impaired