An outbreak of brown tide being blamed for a massive fish kill in the northern Indian River Lagoon is dissipating, according to the latest reports.
But scientists are worried it may signal a tipping point for a crippled ecosystem that makes up nearly one third of Florida’s east coast.
The Florida Fish and Wildlife Conservation Commission is the lead response agency when an outbreak like brown tide occurs. Executive Director Nick Wiley took a recent tour of the Banana River, from Kennedy Space Center to Patrick Air Force Base in Cocoa Beach.
“It’s naturally a brown tint, but you can see through it. But it was still pretty cloudy in a lot of places, showing that we’ve still got some brown algal blooms. I saw actually very few floating fish. It seems the fish kill has waned pretty significantly.”
Experts blame brown algae. Measurable concentrations started rising in late fall, says Zack Jud, director of education for the Florida Oceanographic Society.
“And what we saw last week was a situation where the bloom suddenly crashed, meaning that all the algae died off. And as the algae died, their remaining cells were devoured by bacteria that pulled oxygen out of the estuarian waters.”
A freeze caused a major fish kill in 2010, but this one was worse, Jud says. It claimed millions of fish, everything from blue crabs and bait fish, to spotted trout and red drum. He estimates 50 species were involved.
Blooms start when fertilizer from farms and front lawns and pollution from septic tanks wash into the lagoon. The phosphorous and nitrogen make tiny plant populations explode.
Jud says not enough is being done to limit runoff.
“The Indian River is being attacked on multiple fronts, and until we address all of the various issues we’re not going to have a healthy system. We need to react, and we need to fix the problems now.”
An unprecedented “super bloom,” of green algae struck the northern half of the lagoon in 2011 and lasted an unprecedented eight months. It killed 60 percent of sea grasses in the affected area, reversing decades of recovery.
Harbor Branch Oceanographic Institute researcher Denis Hanisak is worried the latest ecological disaster may eventually confirm suspicions the super bloom signaled a tipping point.
Brown algae first showed up after the super bloom, he says.
“I think that it was a clear warning that we we’re close to a tipping point. It’s kind of a subjective call.”
Governor Rick Scott reminded reporters this week his administration has directed 60 million in restoration projects in the past three years. This year, more than 20 million will be spent on dredging projects to remove polluted muck.
Florida Department of Environmental Protection deputy secretary Drew Bartlett says regulators are working on plans to keep the nutrients out.
“We are in the process of developing projects with local governments, local drainage districts, to further limit pollution getting to the lagoon.
Meanwhile, scientists say they won’t be surprised to see more blooms this summer.