'The System Is More Fragile' Marine Biologist On Nutrient Pollutants Causing Biscayne Bay Fish Kills

MIAMI (CBSMiami) - Below the surface of Biscayne Bay there is a problem, it's a problem that surfaced again this summer.

"I started seeing all these fish trying to get some oxygen and then I realized they are all going to die soon," said Fernando Fiskman.

He lives on Biscayne Bay and could see and smell the problem one September morning.

"The basic driving factor is these organisms are being stressed because they don't have enough oxygen near the bottom where they live," said Chris Langdon, a marine biology professor at the University of Miami's Rosenstiel School of Marine and Atmospheric Science.

He's familiar with these fish kills, one just happened last year.

"Normally these events don't happen back to back," he said.

It's the reason he was out on the bay a few days later, taking water samples and other measurements in specific areas.

"Low oxygen seems to be forming in very specific areas so we are trying to see why it happens and spreads out," said Langdon.

Recent findings are not good. Normally the water should contain six grams of oxygen per liter. Some of his samples were less than two or even one. That's not enough to support life, he said.

The spots showing the lowest concentrations of oxygen in this study were located near canals.

"Those canals are a source of fresh water and a source of nutrient runoff," said Langdon.

Nutrients come from fertilizer and septic tanks which now struggle against a rising water table. Combine this with light wind and warm temperatures and you get a series of events that leads to low oxygen and less seagrass.

"The system is more fragile is a way to put it due to nutrient pollution," said Langdon.

That means events like the recent fish kill are likely to become more common during the summer months.

The water samples he took out of the bay will be used to see how we can fix the current problem.

"It will help us figure out which nutrient we should be most concerned about controlling," he said.

It will also be compared to other samples to determine if the situation is getting better or worse.

It's a concern for him and those that live on or around the Bay.

"This is something we can't leave to the politicians. This is something we need to be conscious about as well," said Fiskman.