November 2024 eNewsletter

Predicting Algal Toxins with Advanced Buoy Sensors
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This buoy is deployed near Bay Beach in Green Bay, Wisconsin. In addition to advanced optical sensors, this buoy also contains a high-resolution video camera. Photo Credit: Todd Miller.

Advanced buoy sensors are at the forefront of predicting algal toxins and cyanobacterial harmful algal blooms (cHABs) around the Great Lakes region. Cutting-edge sensors provide real-time data on water quality and environmental conditions, enabling more precise forecasts of toxin concentrations. By integrating these data into sophisticated nowcast models, researchers can better understand the dynamics of cHABs and anticipate their impacts. This proactive approach is essential for safeguarding water quality, protecting public health, and preserving the ecological balance of cHAB-prone areas, such as Green Bay. Green Bay is the largest freshwater estuary in the world and a major transition zone between riverine input and the blue waters of Lake Michigan, draining over 15,000 square miles of land. Due to high levels of nutrient pollution and increased cHAB occurrence, the lower Green Bay and its principal tributary, Fox River, are designated as a Great Lakes Area of Concern. 

Most of the severe cHABs occur in lower Green Bay near the Fox River outlet and are dominated by Microcystis species that produce the microcystin toxin. Surprisingly, little research has been conducted on the drivers and constraints of cHAB and toxin formation in Green Bay and how they relate to other Great Lakes environments. Todd Miller, PhD, and his research team from the University of Wisconsin-Milwaukee are updating buoys with new equipment and high-resolution sensors to collect data on Green Bay cHABs, toxin concentrations, and other variables to compare the timing of bloom events in lower Green Bay with other areas of the Great Lakes. “For the past five years, buoys have been stationed in the southeastern part of lower Green Bay to gather a range of water quality information,” said Miller. “However, these buoys were built on outdated platforms that do not contain proper dry wells for electronics, they are cumbersome to deploy, and are now aging. In addition, these buoys lack some of the more advanced instrumentation for water quality monitoring that are more commonplace in other systems (e.g., Lake Erie).”

Currently, the Green Bay buoys provide water quality and weather data measurements for scientists, the local parks, water quality and natural resource managers, weather modelers (National Weather Service), anglers, and other recreationalists. “We have found that cHABs and their toxins can increase in swimming areas in a matter of hours,” said Miller. “With the recent interest in developing the lower Green Bay shoreline, including a new swimming beach, these buoys may provide early warning of toxic blooms that will help protect the public. Our research group is working to replace the buoy platforms with more modern, appropriate systems. We are also upgrading the sensor suite to include fluoroprobe pigment sensors for quantifying major classes of algae and in situ nitrate sensors to monitor for nutrient pollution. The improved buoys will be deployed in lower Green Bay from May until October.”

“If we hope to compare and contrast drivers of blooms across the Great Lakes, then adequate comparable measurements of water quality need to be collected,” said Miller. “Our team is utilizing the buoy data to enhance nowcast models for estimating near-future levels of cHABs, toxin concentrations, pollutants, and other environmental factors.” Unlike traditional forecasting models that predict conditions days or weeks in advance, nowcast models focus on providing immediate or near-term information based on the most recent data. The lower Green Bay buoys will be equipped with a variety of advanced optical sensors to detect algal pigments and nutrients, providing data to improve toxin modeling efforts. 

“The outcomes of this work will significantly enhance our understanding of the timing and occurrence of toxic cHABs in lower Green Bay compared to other regions of the Great Lakes, such as Lake Erie,” said Miller. “This comparative analysis will not only shed light on the specific conditions that lead to cHABs in different areas, but also help us identify patterns and trends across various environments. By examining buoy data from locations that experience toxic cHAB events, we can develop more accurate and timely models for predicting these blooms. This information is crucial for making informed decisions and ensuring public safety, as it enables proactive measures to mitigate the impacts of cHABs on both the environment and human health.”