CYANOBACTERIA MONITORING

The Nature Conservancy conducts weekly cyanobacteria monitoring at eight water bodies in the Providence/Cranston area, typically from June through November. This monitoring follows the EPA’s Cyanobacteria Monitoring Collaborative protocol. At each site, field data sheets are completed, documenting weather conditions, advisory signage, and recreational use.

 

The monitoring process begins with a visual inspection of the water body for signs of a cyanobacteria bloom. Photographs are taken, and if a bloom is observed, water samples are collected using a plankton net, then brought to The Nature Conservancy’s lab for identification. The results are then uploaded to iNaturalist for further confirmation. Next, water quality analysis is performed using an AIM science handheld fluorometer. This device measures chlorophyll-a and phycocyanin pigments, both key indicators of cyanobacteria.

 

This analysis is crucial, as it can detect cyanobacteria presence even when no visible signs of a bloom are apparent. If phycocyanin levels reach 50 µg/L or higher, further testing is conducted to assess the bloom’s toxicity. If elevated toxin levels are found, the Rhode Island Department of Health (RIDOH) and the Rhode Island Department of Environmental Management (RIDEM) are notified, and an advisory warning may be issued. Data from previous cyanobacteria monitoring can be found HERE.