The Role of Aquatic Plants at Lake Mohawk
- Aquatic Plants Clarify Water – A well balanced aquatic plant community makes the water clearer in several ways through sediment stabilization and nutrient absorption. Phosphorus as you may know is the nutrient primarily responsible for blue-green algae (cyanobacteria) blooms. Non-vegetated lake sediments that are stirred up by wind, wave, and boat motor actions contribute significant amounts of phosphorus into the water column where it fuels blue-green algae blooms. Aquatic plants absorb phosphorus from the water as a nutrient which then limits the amount available to toxic blue-green algae. There is also some evidence that suggest that aquatic plants secrete inhibitory chemicals against blue-green algae.
- Aquatic Plants Provide a Food Base and Habitat for a Healthy Fisheries – Aquatic insects (invertebrates) thrive within submersed aquatic vegetation which is an important food base for young fish and fry. Aquatic plants also play an important role in providing protective habitat to the young fisheries as they mature.
- Lake Management Approach and Goal – Our collective lake management goal at Lake Mohawk is to balance the needs and wants of a variety of recreational users and property owners throughout the season without jeopardizing the long term health of the lake. Maintaining a healthy and well balanced aquatic plant community naturally reduces the intensity and frequency of cyanobacteria blooms. Blue-green algae blooms almost always require relative large amounts of copper based algaecides like copper sulfate to be utilized in order to keep the lake open for recreation during the summer. As the chart above indicates, copper is not biodegradable and therefore can accumulate in the lake sediments over time. Long term accumulation of copper in lake sediments results in toxic conditions where aquatic plants cannot live while also being toxic to aquatic invertebrates (fish food). The fewer the plants…..the more copper is needed to control the algae blooms and the cycle continues and repeats itself with the lake sediments becoming more toxic with each and every application of copper.
Algal Succession
It’s important to note that most all northern dimictic lakes (2 mixes per year-spring and fall) go through a phytoplankton (microscopic algae) succession. It is a normal process driven by a variety of factors such at temperature, nutrient availability, depth, weather conditions, etc.. Think of succession just like we have a succession (change) of terrestrial plants throughout the season. It is perfectly normal and natural that blue-green algae has a spike in population starting in July, peaking in August and September and then decreasing at the end of fall. Note also that blue-green algae is ALWAYS present to some degree. Blue-green algae are some of the oldest organisms on earth and exist in many environments.
