Waters of northern Florida Bay turned clear this week, raising some hope that the South Florida sun may initiate the long process of environmental recovery.
However, clarity of the water also clearly exposes the extent of the problem — a mottled bottom marked by vast expanses of yellow mud bottom where seagrasses should flourish.
“It should be dark green, like a lawn,” Stephen Davis, wetlands ecologist for the Everglades Foundation, said on a Monday field trip.
Scattered patches of shoal grass have taken root in some waters, a hopeful sign that the ecologically critical turtle grass could follow.
Yet Davis noted that following the 1987-91 seagrass die-off in many of the same waters off the Florida mainland’s southern tip, “it took about 20 years to get turtle grass back to its pre-die-off levels” on nearly 100,000 acres.
And as summer temperatures return, problems “perhaps could be more extensive and more acute” than current estimates of about 50,000 acres of devastated sea grass ranging from the Crocodile Dragover on the east to Johnson Keys on the west.
Charter captain Matt Bellinger vividly remembers August 2015 when a stretch of more than seven miles of seagrass in shallow waters “died overnight” and came floating to the surface like a carpet. “You could not throw a lure and hit an open spot on the water,” Bellinger said. “The day before, it was fine.”
Once sea grass starts dying, decaying material can cause a surge in nutrients that makes conditions worse. “Zombie grass,” David called it.
Fish flee or perish, depriving bottlenose dolphins and aquatic birds of food. Bellinger pointed to a mangrove root along a bay channel. “There should be schools of snapper right there, along with three or four snook,” he said.
Tough fishing — some Key Largo guides reported running miles out of their way to seek sea trout that should be plentiful — has an even larger economic impact, said Andrew Stainback, an ecological economist working for the Everglades Foundation.
The nonprofit organization founded by the late George Barley Jr. of Islamorada in 1993 this week released a study on Florida Bay’s economic effect on the Florida Keys and South Florida.
Recreational fishing alone in Florida Bay accounts for $213 million annually in the South Florida area including Monroe, Miami-Dade and Collier counties, Stainback calculated. “That’s what it’s worth to people to go fishing in Florida Bay,” he said Monday.
Coupled with the money that anglers spend on gear, hotels, restaurants and other related expenses, the annual impact in South Florida likely exceeds $430 million and creates 4,100 jobs, Stainback said.
“Even if somebody is not an environmentalist, they should care about the jobs and the economic activity that Florida Bay creates,” he said.
Commercial fishing for pink shrimp and snapper off the Dry Tortugas would not exist without Florida Bay providing habitat to juveniles in those species, Stainback wrote.
Ecotourism brings birders and paddlers to explore the bay’s ecosystem, the report notes, and provides habitat to protected species like the American crocodile, Goliath grouper and roseate spoonbill.
Stainback also looked at Florida Bay’s value to real-estate values and to “carbon sequestration” — the ability of ocean plants to absorb carbon dioxide from the atmosphere. “Seagrass beds represent a significant store of carbon that, if they were to disappear, would be released back into the atmosphere and contribute to global climate change and its attendant negative consequences,” the report says.
Dying seagrass also releases nutrients into the water column, possibly creating an algal bloom that causes more problems, it notes.
“People don’t always pay attention to what’s happening underwater,” Stainback said. “They should pay attention to this ecosystem.”
Everglades Foundation’s science staff says that increasing the freshwater flow through the Shark River Slough in mainland Monroe County would send more needed water into Florida Bay to prevent high salinity levels that can start a chain reaction that leads to seagrass die-off.
Plans to send more fresh water into eastern Florida Bay via Taylor Slough are beneficial, Davis said, but provide only a fraction of the bay’s needed water flow.
Copies of the report are scheduled to be posted online this week at EvergladesFoundation.org.
Kevin Wadlow: 305-440-3206