Frequency and Severity of Harmful Algal Blooms (HABs) of Cyanobaceteria and Cyanotoxin (Microcystin) in the Green Bay Area of Concern. (CAP_3_2011)


Cyanobacteria (also referred to as blue-green algae) are known to cause a multitude of water-quality concerns. Harmful Algal Blooms (HABs) produced by cyanobacteria have the potential to produce deadly toxins. HABs can cause a reduction in light penetration and can cause depletion of oxygen in the water column as the algal masses grow and senesce, which ultimately results in degraded water quality conditions. Cyanobacteria toxins (cyanotoxins) have been implicated in human and animal ill¬ness and death in more than 50 countries worldwide, includ¬ing Wisconsin and 35 other states in the United States (Chorus and Bartram 1999; Huisman et al. 2005). Hypereutrophic conditions have been a consistent feature of the Green Bay ecosystem for decades. One of the principal criteria for the southern bay’s designation as an Area of Concern (AOC) are the frequent and severe nuisance algal blooms that result from total phosphorous concentrations often exceeding 100 ug/L at the mouth of the Fox River. Chlorophyll a concentrations range between 24-131 ug/m3. Phytoplankton sampling performed in the early 1990s, near Communiversity Park in the Green Bay AOC, showed a strong dominance in blue-green algae, averaging 76% of the total biovolume (Rhew 1992). Despite the potential of cyanobacteria to generate deadly toxins and contribute to water quality problems, limited research has been done to determine the frequency, severity, and extent to which HABS by cyanobacteria are occurring in the Green Bay Area of Concern (AOC). A recent study performed by Wisconsin Department of Natural Resource (WIDNR) and State Laboratory of Hygiene (SLOH) from 2004 - 2006 of Wisconsin ponds, lakes, and rivers found that 68 -74% of water quality sampled tested positive for the presences of cyanobacteria, with 41-69% of those of samples testing positive cyanotoxins (Hedman et al. 2008). Finally, it is important to note that research by De Statsio (2008) has indicated a shift towards dominance by blue-green algae since the invasion of zebra mussels.


This project will provide data to evaluate the current status of 2 BUIs in the Green Bay AOC that have a delisting target for cyanobacteria, “Beach Closings/Recreational Restrictions” and “Eutrophication/Undesirable Algae” and provide supplemental information for “Degraded Phytoplankton / Zooplankton Populations”. The work will also supplement phytoplankton monitoring that is currently being conducted by Dr. Bart De Stasio of Lawrence University. Sampling for cyanobacteria will be performed in conjunction with bacteria sampling at two Beach Health locations within the Green Bay AOC (see map attachment, Communiversity Park #25 and Longtail Point #32). Currently, sampling and monitoring for bacteria in the Green Bay AOC is being performed by GBMSD and the Brown County Health Department. Coordination of sampling efforts for cyanobacteria and cyanotoxins with bacteria sampling will allow for a simultaneous assessment of the Recreational Restrictions BUI. Seasonal patterns in cyanobacteria abundance and community composition are affected substantially by tem¬perature, solar irradiance, and nutrient supply (Graham et al. 2008). Cyanobacteria populations tend to peak between mid-summer and early fall when water temperatures reach a seasonal maximum and nutrient concentrations are at a seasonal low (Wetzel 200; Falconer 2005). HABs in the Green Bay AOC become evident in mid-July when water column temperatures generally peak, which also coincides with depleted nitrogen concentrations. Cyanobac¬terial populations may also vary on a much shorter time scale (hours or days). Thus, it is important to use GBMSD’s local knowledge of conditions, including patterns in circulation, mixing, and prevailing winds (Chorus and Bartram 1999; Falconer 2005). GBMSD’s Ambient Water Quality Monitoring (AWQMP) program has been sampling water quality in the AOC and surrounding waters weekly from May through October since 1986. Sampling for cyanobacteria will begin during the month of July when visual signs of cyanobacteria blooms begin and will continue through September or senescence. Sampling will typically be conducted in the AOC where exposure to cyanobacteria toxins poses the greatest threat to recreational users and human health (see map attachment). Sampling will occur approximately six times from July through September. A single grab water sample will be collected directly from the bloom in conjunction with a bacteria sample using a Van Dorn water sampler. Vertical profiles will be taken to assess limnological characteristics such as temperature, specific conductance (umho/cm at 25 C°), pH (SU), dissolved oxygen (mg/L) and percent saturation. Readings will be taken continuously throughout the entire water column until the sediment is reached. A Li-Cor light meter will be utilized to determine the light extinction coefficient. A Secchi disk will be used to determine water clarity. Cyanobacteria samples will be preserved and transported to the State Lab of Hygiene for analysis. The samples will be analyzed for total algal composition to genus level because many variants of these cyanobacteria can produce toxins. Samples will also be analyzed for presence of the cyanobacteria Microcystis aeruginosa. Samples will be analyzed by GBMSD’s laboratory for Chlorphyll a concentrations.


: Sampling will occur biweekly from July through September during the summers of 2011 and 2012, if funding is available for the two year time period. Analysis of the data will occur during the winters of 2012-13. Publication of the data in the form of report will be written and delivered to the WIDNR by June of 2012 based on completion of the first year of monitoring. A subsequent report will be written and delivered to the WIDNR in June 2013. The data will also be made available and presented to the AOC Social Uses group who developed the delisting targets for review. The final write up of the data will be provided to the University of Wisconsin Seagrant for possible publication in the State of the Bay Report. Data will also be provided to the WIDNR Beach Monitoring Program for publication on the following website:

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Great Lakes Restoration Initiative
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Reports and Documents
Final report for Frequency and Severity of Harmful Algal Blooms (HABs) of Cyanobacteria and Cyanotoxin (Microcystin) in the Green Bay Area of Concern Project (2011 AOC Capacity grant)
Background information on uploading the laboratory data
Invoices and test costs
Approved QAPP with signatures
Grant Report
Application for grant