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The Indian River Lagoon: An estuary in distress
The Indian River Lagoon is a diverse, shallow-water estuary stretching across 40 percent of Florida’s east coast. Spanning 156 miles from Ponce de Leon Inlet in Volusia County to Jupiter Inlet in Palm Beach County, the lagoon is an important commercial and recreational fishery and economic resource to the state and region. The total estimated annual economic value of the lagoon is $3.7 billion, supporting 15,000 full and part-time jobs and providing recreational opportunities for 11 million people per year.
The people attracted to the lagoon by its features — its vast diversity of marine life, plants and animals; temperate climates; accessibility and direct links to the Atlantic Ocean — have changed those characteristics over the last century and particularly within the last 50 years. Throughout recorded history, there have been fish kills, algal blooms and changes in water quality. The lagoon has had a natural capability to absorb a certain amount of pollutants. However, when overloaded, the lagoon suffers.
In spring 2011, an algal “superbloom” occurred in the portion of the system known as Banana River Lagoon and eventually spread into northern Indian River Lagoon and farther north into the Mosquito Lagoon (see map). The immense bloom covered approximately 130,000 acres and led to a noticeable reduction in water quality. Concurrently, a lesser bloom extended from just north of Melbourne south to the Vero Beach-Fort Pierce area (see map).
Approximately 47,000 acres of seagrasses were lost, a reduction of about 60 percent. These blooms and the resulting seagrass decline far exceeded any documented or remembered events in terms of geographic scale, bloom intensity and duration.
The magnitude of the seagrass loss is alarming because seagrass is:
- An indicator of the lagoon’s health
- A food source for manatees
- A nursery, refuge and a place of forage for a variety of fish and other marine life
Also in August 2012, a brown tide bloom began in the Mosquito Lagoon and moved into the northern Indian River Lagoon near Titusville. Compounding concerns are the mounting losses of manatees and pelicans since July 2012 and bottlenose dolphins since Jan. 1, 2013. State biologists are investigating the deaths of approximately 100 manatees, between 250–300 pelicans and 29 bottlenose dolphins to determine whether there is a link to the blooms or the loss of seagrass.
In economic terms, the 2011 seagrass loss represents a potential reduction of $235 million to $470 million in commercial and recreational fisheries value in 2012.
Following years of positive trends — including the expansion of seagrass coverage — the lagoon is at a turning point. The coming months could herald a slow recovery of this unique ecosystem or a continued decline. Scientists, biologists and specialists are redoubling their efforts to determine strategies for improving the long-term health of this waterway.
Why did the superbloom occur? Many factors were in play, elements that may have contributed to a “perfect storm” of sorts. Preceding the blooms, long-term droughts had increased salinities in the lagoon and extremely low water temperatures occurred during the winters of 2010 and 2011. These extreme climatic events in conjunction with chronic, decades-long nutrient enrichment may have favored certain algae species that had previously never reached bloom proportions. While no single factor explains the superbloom, it is likely that these and other events contributed.
The St. Johns River Water Management District, Indian River Lagoon National Estuary Program, federal and state agencies, local governments and educational institutions are individually and collectively working to find answers to the cause of the superbloom and to identify what, if anything, can be done in the future to limit or avoid a similar event. The various partners are investigating the possible causes of the blooms and developing strategies to reduce their magnitude, duration and frequency. Chief among this work are the Indian River Lagoon 2011 Consortium and the District’s Indian River Lagoon Protection Initiative. The Initiative is being developed to better understand the sources, cycling and transport of lagoon nutrients and the long-term impacts from the loss of the lagoon’s seagrasses, as well as potential strategies aimed at restoring the lagoon to a seagrass-dominated ecosystem.
The current work builds on years of collaborative research and projects that have included:
- Cost-share stormwater projects that capture sediments before they reach the lagoon
- Large regional projects that include dredging muck from major tributaries in the lagoon
- Coastal wetland restoration projects
- Water quality and sediment studies by several state agencies and educational institutions
- Seagrass mapping and monitoring by the St. Johns River Water Management District
- Water quality monitoring by the St. Johns River Water Management District
- Monitoring of fish populations by the Florida Fish and Wildlife Research Institute
The St. Johns River and South Florida water management districts sponsor the Indian River Lagoon National Estuary Program, which works with a network of partners and has implemented more than $80 million in projects to improve water quality in the lagoon.
Since 1999, the lagoon program also has assisted local governments in securing grants for lagoon restoration efforts. This program has brought an additional $200 million in capital improvements and preservation dollars.
Hank Largin at (407) 659−4836 or firstname.lastname@example.org.
Updated on 5-16-2013