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OUR INDIAN RIVER LAGOON

Brown water is bad What’s in it is worse

TYLER TREADWAY

TYLER.TREADWAY@TCPALM.COM

Coffee-colored water now spreads throughout the St. Lucie River into the southern Indian River Lagoon, out the St. Lucie Inlet and south several miles along the Atlantic Coast beaches.

The water is a combination of rainfall runoff from western Martin and St. Lucie counties and Lake Okeechobee discharges since Hurricane Irma struck in September.

Farther north, about 20 billion gallons of post-Irma rainwater runoff has poured out the C-54 Canal along the Indian River-Brevard county line and into the lagoon.

In between, brown water from western farmland extends into the lagoon from the mouth of Taylor Creek north of Fort Pierce.

“What’s worse than the color of the water is what’s in the water,” said Grant Gilmore, a marine biologist who’s studied life in the lagoon for more than 40 years.

The Treasure Coast always has had hurricanes and lots of rain in the early fall, said

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Above: Dirty water filled with sediment and toxins in the Indian River Lagoon spews out from the Fort Pierce Inlet into the Atlantic shoreline as seen on Wednesday in Fort Pierce. ERIC HASERT/TCPALM


Brown

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Gilmore, lead scientist for Estuarine, Coastal & Ocean Science in Vero Beach, “so brown water going into the lagoon is nothing new.”

But with the silt-laden brown water comes “all the chemicals we put on our crops and our lawns,” Gilmore said. “The chemicals kill the plankton in the river and lagoon that all the fish depend on for food.”

The pollutants in the water would have a bigger impact on fish in the lagoon if they were still hanging around, Gilmore said. Luckily, a lot aren’t.

“The influx of brown water each fall is the signal for a lot of fish species to head out to the ocean to spawn,” he said.

No escape

Oysters and sea grass can’t flee from the brown onslaught, and they’re dying simply because the influx of freshwater lowers the salinity they need to survive.

“There’s been basically no salinity in most of the St. Lucie River since the hurricane four weeks ago,” said Vincent Encomio, a researcher at Florida Oceanographic Society in Stuart. “We’re at the threshold of high mortality.”

As go the oysters, so go many other marine species.

“Oysters are a keystone species,” Encomio said. “They provide habitat for a lot of other species, most of them other species that have the same need for salty water.”

Encomio also works with the Smithsonian Marine Station in Fort Pierce to study mussels in the river and lagoon, “but when we went out to collect mussels for the study, they were all dead.”

The extra-high tides that threatened to flood low-lying areas along the river last week actually did the oysters a favor by pushing more saltwater into the river.

“The so-called king tides helped a little in the lower part of the river,” Encomio said, “but it’s just not enough.”

Brown, not green

There’s still a possibility the discharges could spur blue-green algae growth in the river, Encomio said, although probably not to the extent of the massive toxic blooms that blanketed the St. Lucie River last year.

“The big difference from last year is that there’s not a big bloom out in Lake Okeechobee that’s being brought to the river by the discharges,” he said.

But conditions needed for a bloom — low salinity, warm water, sunny days and lots of nutrients in the water — are all in place.

“We could see some smaller blooms in the impounded water along the river,” Encomio said.

The dirty water shouldn’t impede sea turtles crawling onto local beaches to nest or their hatchlings heading into the water, said Niki Desjardin, senior scientist at Ecological Associates Inc., a Jensen Beach firm that monitors turtle nesting along the Treasure Coast.

“Water quality changes from time to time, so the turtles are used to it,” Desjardin said.

Dirty water from the Indian River Lagoon empties into the Atlantic Ocean through the St. Lucie Inlet in Stuart on Wednesday, discoloring the water south along the beaches of Hobe Sound in southern Martin County. Excess water from Lake Okeechobee released through the St. Lucie Locks flowing along the St. Lucie River in Martin County empties into the Indian River Lagoon, causing toxic conditions and discoloration in the lagoon, which eventually flows through the inlets into the Atlantic Ocean with the changing tides. ERIC HASERT/TCPALM

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