The aim of this study was to establish a simple and cost-effective method to monitor the effects of harmful algal blooms as exemplified in Lake Powsinkowskie, and to link the monitoring results to potential health risks on the basis of established Alert Level Frameworks.
An assessment of the severity of cyanobacterial development in Lake Powsinkowskie (52°9'27"N, 21°5'55"E), located in the Wilanów region, Warsaw, Poland, was performed to illustrate this. An Alert Level Framework based on cyanobacterial chlorophyll-a measurements was applied. Measurements of cyanobacterial chlorophyll-a in Lake Powsinkowskie were performed once per week at 10 locations on each side of the lake from May to July 2012. The highest algal densities were expected at the eastern side of the lake due to the use of fertilizers on the fields along the eastern shore, however, the opposite was observed. It seems that the conditions on the west side of the lake were more favourable for cyanobacterial growth.
This study shows that an indication of the overall effects of eutrophication on algal growth and the potential risk of the presence of toxic cyanobacteria can easily be obtained using relatively simple, simultaneous measurements of total and cyanobacterial chlorophyll-a. The Alert Level Framework based on cyanobacterial chlorophyll-a levels is a rapid and easily applicable method for determining the severity of cyanobacterial developments.
The findings of this study indicate that a reduction in nutrient loading to protect Lake Powsinkowskie’s unique species richness can be achieved by informing the local residents about the effects of draining cesspools directly into the lake. Studies such as this one can thus help to support awareness-raising among lake-side residents.