In race to prevent more fish kills, governments deploy pumps on Biscayne Bay shores

With the northern area of Biscayne Bay temporarily starved of oxygen, environmentalists and governments raced to use massive pumps this weekend to recirculate some of the sea water and pump it with air.

Modifying a technique typically used in ponds and canals, a county fire boat spent Friday and Saturday pumping bay water into its hoses and the spraying it in high into the air in the shallows near North Bay Village. With the water mixing with air, oxygen levels should be higher once the liquid returns to the bay.

“In principle, taking low-oxygen water from the water column and spraying into there should greatly increase the oxygen molecules that bind” to the seawater, said Todd Crowl, executive director of the Institute of Environment at Florida International University.

Miami on Saturday began setting up ground-level pumps at the water’s edge of several parks in order to create more oxygenated water there. Usually used to pump seawater from land to sea, this time the pumps will be used to pour bay water back into the bay directly after mixing with the air.

“This was a Hail Mary,” said Rachel Silverstein, executive director of Miami Waterkeeper, the environmental group that’s been rallying the response to a fish kill that was discovered on Biscayne this week. The group blames the die-off on low oxygen levels caused by a mix of high nutrients and unusually warm waters, along with a lack of breeze to stir up the surface and allow more air to be absorbed by the waves.

Silverstein said the fish kill was almost certainly the worst in modern times for Biscayne Bay, and a turning point after years of pollution, unchecked storm-water run-off, sewage leaks and other factors that have killed sea grass and made the bay more vulnerable to algae blooms and other hazards to aquatic life.

“This is a known pattern of how a body of water dies,” she said. “This is the Bay on life support.”

Silverstein said her group contacted the county’s Port Miami on Friday, which led to Miami-Dade dispatching a fire boat from the port station to begin the pumping operation near North Bay Village. Miami Mayor Francis Suarez on Saturday announced the deployment of pumps at three waterfront parks: Albert Pallot, Margaret Pace and Morningside.

“This is just a Band-Aid on a car wreck,” City Commissioner Ken Russell said during a Facebook Live broadcast in front of one of the city pumps gushing seawater into the bay at Morningside.

Pumps aren’t a long-term solution, and are being used in hopes of creating some shallow areas with more oxygen to be a refuge for fish fleeing depleted waters, Silverstein said. A research team from FIU was measuring oxygen levels Saturday, but were unable to get the kind of before-and-after readings needed to say whether the operation was working. “Fingers crossed it improves the situation,” researcher Cody Eggenberger wrote in an email to Silverstein Saturday evening.

Silverstein said even if the pumps save some fish, Miami-Dade needs to rapidly address the Biscayne crisis in order to preserve sea life there. Steps she wants include ending the use of septic tanks, replacing an aging sewer system and creating a system to trap and treat rainwater instead of rushing it to the sea while collecting fertilizer, animal waste and other pollutants along the way.

“We’ve been warning about this happening for years,” she said.

This article was updated to correct the name of Albert Pallot Park.

This story was originally published August 15, 2020 at 8:00 PM.