Harmful algal blooms (HABs) are a perennial threat to public health and coastal economies dependent on fishing and tourism. Nationwide, these blooms are becoming more frequent, making the need to understand and manage them a priority for all coastal states. A new study has positioned the National Estuarine Research Reserves System-Wide Monitoring Program to support algal bloom research, management, and education through enhanced chlorophyll monitoring.

“Chlorophyll is often used as a proxy to track phytoplankton, including the kind involved in harmful algal blooms,” says Nikki Dix, research director at the Guana Tolomato Matanzas Reserve in Florida. “Reserves have monitored chlorophyll for years with monthly samples that we process in the lab. This is really valuable for understanding long-term trends, but it doesn’t tell us much about what’s happening in the short-term and phytoplankton populations change hourly.”

Dix worked with scientists at 12 Reserves in geographically diverse regions to explore the merits of using new optical sensors to capture continuous, real-time chlorophyll data. With funding from the NERRS Science Collaborative, the team deployed the YSI EXO TAL sensor at fixed monitoring stations, explored possible sources of error, and compared real-time chlorophyll readings to monthly samples processed in the lab.

“We found a relationship between the sensor data and the monthly snapshot from the lab, ” says Dix. “This gives us confidence that Reserves can use this technology to provide reliable data, but we also found that things like temperature and suspended sediment can influence the sensor readings and it’s important to understand and account for that limitation.”

Both approaches, she says, can provide valuable data to support the NERRS mission to study changes in estuary condition and use that science to help coastal communities. Real-time monitoring data, for example, could support early detection of, and response to, algal blooms, allowing public health agencies to alert beachgoers, swimmers, and ecotourism operators.  It also could support the management of aquaculture farms. Combined with the Reserve’s historic dataset, it can also support research on topics ranging from harmful algal blooms to coastal acidification and educators interested in using place-based data to inform their curricula and programs.

“This is a big step forward for Reserves as they keep watch over how our nation’s estuaries are changing,” says Rebecca Roth, director of the National Estuarine Research Reserve Association. “In the 50 years since the Coastal Zone Management Act was authorized, the Reserve System has built a powerful monitoring network with a unique data set that is informing proactive solutions not only to harmful algal blooms, but many other challenges faced by our coastal communities.”

Data, reports, and other resources from this project will be available at the NERRS Science Collaborative website.