District shares series of articles on science behind algal blooms, continues partnerships to address causes

Feb. 10, 2022

scientist carries a transect in the Indian River Lagoon

A District scientist carries a quadrat used for monitoring seagrass transects in the Indian River Lagoon.

St. Johns River Water Management District scientists and partners are sharing data, analyses and insights to help improve water quality in the Indian River Lagoon region and beyond. The first of seven peer-reviewed scientific journal articles with a District scientist as lead author has been published in the Marine Ecosystem Ecology section of the journal “Frontiers in Marine Science.”

A series of 24 articles is expected to be completed in 2022 as the District continues to collaborate with the Florida Department of Environmental Protection, Florida Fish and Wildlife Conservation Commission and others to document conditions stemming from the 2011 “superbloom” in the 156-mile-long estuary along Florida’s east coast. Through their collective efforts, the District and partners are seeking to enhance  projects and practices addressing causes of algal blooms and impairment of the lagoon’s water quality.

The recently published article, “Seagrass in a changing estuary, the Indian River Lagoon, Florida, United States,” examines how the distribution and abundance of seagrasses in the lagoon respond to salinity, temperature and availability of light. Data collected indicate that algal blooms, fueled by excess nutrients (primarily nitrogen and phosphorus), contributed to shading in the waterway, restricting the sunlight essential for growth of seagrass. Less seagrass disrupts the ecology of the Indian River Lagoon because seagrass is a critical structural habitat in this and other waterways. Other factors impacting underwater vegetation include disturbance of sediments by wave action that cause turbidity in the water, which also reduces the availability of light, and competition for nutrients with phytoplankton (microscopic plants). Read the journal article here.

District staff inspecting buckets of young clams

District staff and staff from the Restore our Shores conservation team at Brevard Zoo inspect buckets of young clams before distributing the clams in the lagoon as part of a District cost-share project to enhance clam repopulation.

Other articles currently being written for the series cover topics such as changes in drift macroalgae, phytoplankton dynamics and use of different forms of nutrients, changes in fish populations, use of remote sensing to identify “hot spots” for phytoplankton blooms, and influences of tributaries on the lagoon.

District experts are the lead author or a co-author on 13 of the 24 journal articles, which are being independently peer reviewed. District authors for this first journal article are Lori J. Morris, Lauren M. Hall, Dr. Charles A. Jacoby and Janice D. Miller; former District staff members Dr. Robert H. Chamberlain and Dr. Robert W. Virnstein; and Dr. M. Dennis Hanisak, a research professor at Florida Atlantic University. Combined, these scientists have more than 100 years of experience working in the lagoon region.

“I’m proud of the commitment by our District scientists and experts as they tackle these complex issues that affect not only the Indian River Lagoon, but all the waterways that we are working to restore and protect,” says St. Johns River Water Management District Executive Director Mike Register. “Many of our staff members have built careers working in and along the lagoon and have a personal interest in helping to see it restored to better health.”

The scientific articles now going to publication build off both long-term data and studies conducted in response to the 2011 superbloom of phytoplankton, and they incorporate new scientific techniques.

“One of the great strengths that our staff display in dealing with these intricate issues is their ability to adapt to changes. Those changes could be in the conditions in a water body, in the way they find solutions or in trying new things based on what the latest data are telling us,” says Register. “Collaboration among internal and external work groups is key to successfully helping the lagoon recover.”

In recent years and in response to research on the superbloom, the District has worked with many partners to complete hundreds of millions of dollars in projects to improve water quality and restore habitats. Among the larger District-led projects has been the dredging work to remove accumulated “muck” (nutrient-rich sediment) and the associated “legacy loads” of nutrients from Crane Creek, Turkey Creek, the St. Sebastian River and the Eau Gallie River. The District also has built large stormwater parks, such as the Micco Water Management Area in Brevard County, that is expected to capture an average of nearly 17,000 pounds of total phosphorus and 27,000 pounds of total nitrogen each year before the water reaches the lagoon. Reducing nutrient loads and removing excess nutrients already in our waterways improves water quality, lessening the chances of harmful algal blooms.

The District’s long-term monitoring of seagrasses guides the efforts to improve water quality and re-establish this critical habitat. Another of the District’s current projects is a cost-share project to re-establish clam colonies in the lagoon, in partnership with Brevard Zoo, Florida Oceanographic Society and the University of Florida’s Whitney Laboratory for Marine Bioscience. The bivalves filter water, helping to improve water quality by feeding on algae and removing suspended sediments.

“Our board is committed to supporting staff in their work to identify conditions that impact the lagoon, develop solutions and implement projects to restore this waterway,” says Governing Board Member Cole Oliver of Merritt Island. “The funding from Gov. DeSantis and the Legislature in the past two years helps to further the work that we can do in collaboration with local partners.”

More than 60 projects to address water quality in this Estuary of National Significance have been completed or currently are being constructed. These efforts have been supplemented by funding from the state, including $53 million to address nutrient loads from wastewater and $25 million in fiscal year 2020–2021 that allowed the St. Johns and South Florida water management districts to fund projects to improve water quality in the lagoon. In September 2021, Gov. Ron DeSantis announced an additional $114 million for wastewater treatment grants to improve water quality across the state, with $53 million of the total granted for lagoon projects.

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