Eurasian Watermilfoil is a species of invasive aquatic plants fond in some eastern Quebec

Eurasian Water Milfoil poses a growing threat to the lakes of Quebec due to its destructive capabilities. Currently present in hundreds of lakes in southern Quebec, Eurasian Water Milfoil threatens other native species of aquatic plants due to its ability to grow in dense canopies. Blocking sunlight from getting to these native species, the introduction of Eurasian Water Milfoil into lakes causes massive habitat loss, changes in the level of dissolved gases as well as a reduction in property value. These plant canopies increase water temperature during the day while reducing dissolved oxygen levels at night but the extent to which these phenomena occur is not well known. What is known, is the presence of this plant on a property can reduce the property value by twenty percent on average. As a result of these human and ecological impacts, there is an increasing degree of interest into possible mitigation strategies against Eurasian Watermilfoil.

The Bishop’s University UBERG team headed by Dr. Elisabeth Levac, has set out to determine the extent to which Eurasian Water Milfoil reduces the level of dissolved oxygen. Using a swarm of profiling buoys, the UBERG team researches a proof of concept strategy to measure how the dissolved oxygen level changes throughout the night. Measurements are done using a DS18B20 temperature sensor and an Atlas Scientific dissolved oxygen probe protected within an aluminum cage. The aluminum cage is attached to a Nema 17 stepper motor, which allows the sensor to measure information at a set of predetermined depths. All information collected by this probe is stored on a micro SD card and managed using an Arduino Mega microcontroller.

Each buoy is equipped with a nRF24L01 radio transmitter to transfer the data acquired by the swarm of buoys to a ‘queen’ receiver. The other buoys, are additionally equipped with a Boletic LTE SIM7000 shield. The queen receiver links the swarm to server, providing a real-time visualization of the data acquired by the profilers.

Testing of this project is currently underway at Brompton Lake’s Baie Nickel. The first survey of this bay was done in 2016 and indicated that at the time, Eurasian Water Milfoil was present in low density. However, as of 2022, Eurasian Water Milfoil is now Baie Nickel’s predominant species. Restoration operations are carried out by a team of scientific research scuba divers while testing is underway. The goal of this is to monitor of the impact of the restoration process.

Temperature and dissolved oxygen concentration profiles were taken in the Lac des Nations in proximity of Moncalm Bridge on May 12th, 2019. Downward and upward profiles were consistent, with ±0.1 mg/l of dissolved oxygen through the water column. Water temperature increased from 7.4 to 8.4°C between 3AM (night) and 4PM (day) acquisition. Preliminary tests of this swarm of profiler buoys show promising results to monitor health parameters in a lacustrine environment. Additionally, the low-cost ratio for each buoys increases the incentive for lake associations to install these profiler buoys to monitor water quality of their lake.

Lake bed Quadrants for the study of interventions impact and species processions

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