09/23/2022
An ongoing issue in the municipality has been the water at the park, multiple residents have also brought this up. The aerator fountains that are in the in the lake obviously are not doing what they were intended for. The motor is broken on the one and apparently can’t be replaced as it is no longer available. a primary concern for lake health is nutrient loading. The right amount of nutrients is required to maintain a healthy, productive lake. Too little and life cannot be sustained; too much and water quality deteriorates. Phosphorus, nitrogen, and carbon are the major nutrients that impact lake water quality.
Excess phosphorus in a lake environment can stimulate rapid algae growth resulting in altered oxygen levels, water clarity (transparency) and food web interactions. Cumulatively these changes affect the function and health of the lake.
In some lakes, small increases in nitrogen may also stimulate plant and algae growth, reducing the aquatic diversity by providing a competitive advantage to only a few specialized species. This can also impair food webs since phosphorus-limited algae are known to be poor quality food sources for zooplankton.
Dissolved organic carbon is a form of carbon important to consider with regard to phosphorus measurements and transparency, since it reflects the degree to which nutrient-rich wetlands are present in the watershed and can play a major role in lake function.
Phosphorus, nitrogen, transparency, and dissolved organic carbon are further explained below.
Phosphorus
Phosphorus is often the limiting factor for biological growth in freshwater systems when compared to more abundant elements like carbon, hydrogen, nitrogen, oxygen and sulphur. However, in environments with excess phosphorus input, growth of aquatic plants and algae may increase to levels that become a concern for both aquatic life and recreation. This is often referred to as the “productivity” of the lake.
Phosphorus can enter lakes from atmospheric deposition, runoff from adjacent upland and wet- land areas, and nutrient cycling within the lake. Fertilizers, human and animal wastes, plant mat- ter, and the natural weathering of rocks and soils all contribute phosphorus. In addition, internal changes to lake water quality such as reduced oxygen and pH, as well as organism movement, can trigger the release of phosphorus from bottom sediments into the water.
The total amount of phosphorus entering a lake depends on the surrounding bedrock geology, soil type, and vegetation. Changes to soil acidity alter the ability of phosphorus to be retained on the upland areas surrounding lakes versus leaching into the lake. Soil type and the concentration of metal ions such as aluminum and iron determine how easily and how much phosphorus can be bound to the soil, or conversely enter a lake environment. This is important, as many lakes are surrounded by calcareous soils or situated on limestone bedrock, providing an alkaline environment that inefficiently binds phosphorous. Between these areas, soil quality, acidity, nutrient concentrations, and ultimately a lake’s productivity levels are variable.
Total phosphorus is measured in our lakes, as this includes all forms of the nutrient dissolved and bound). Generally, phosphorus samples are taken at the deepest point in a lake. Most organizations take a composite sample at a water depth equal to or twice the Secchi disk depth. The CRCA follows the method prescribed by the Lake Partner Program whereby samples are taken from the Secchi disk depth to the surface. If shallow lakes are encountered, then it is necessary to ensure that the collection is at least one metre off the bottom to prevent the release of any phosphorus stored in the sediments.
The CRCA uses laboratory prepared sample bottles provided by the Lake Partner Program which are filled and sent to Dorset Environmental Science Centre for analysis.
Guidelines have been established by both the Federal and Provincial governments to identify waterbodies that are nutrient rich or nutrient poor. Water Quality Standards for Aquatic Life and Recreation. Nutrient rich lakes are the most productive and are called eutrophic, those with a moderate amount are mesotrophic, and those with the least amount of nutrients are oligotrophic.
Our lake is here forever! It is time we take care it!
