Ocean Habitats systems filter millions of gallons of island water each day
Water quality has become an increasingly urgent issue in Collier County, with dead dolphins washing up on the beach, regular red tide blooms and shorebirds sickening and dying in large numbers.
One Marco Island resident has been on a quest to improve the quality of the water that surrounds the island, and even takes up most of the space within it, through the extensive series of canals that honeycomb the land.
Jim Timmerman, longtime member and chairman of the city’s Waterways Advisory Committee, is a principal of a firm, Ocean Habitats, that has developed a system to cleanse seawater where it meets the land. For three years the company has installed its “mini reefs,” which provide filtration for water in a manner similar to the actions of nature.
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Historically, local waterways were fringed with vast mangrove forests, and water flushed through their prop roots, driven by tidal action. The combination of impervious concrete surfaces and fertilizer and other substances flushing into the area’s waterways from human sources has contributed to the degradation of the island’s water quality. With the development of modern Marco Island, the mangroves were decimated, and canals and seawalls took their place, Timmerman said.
“When the canals were dug, the mangroves destroyed and seawalls put in, all the indigenous species were lost” that used to filter the water, he said. “Our filters mimic the actions of the mangroves.”
Timmerman installed the first Ocean Habitats mini-reef under the dock at his house on a Marco Island canal in July 2015. In April 2016 the Marco Island City Council enacted a resolution allocating $10,000 for a pilot project to install mini-reefs. There are now more than 600 units installed in the waters of Marco Island. Additional mini-reefs are filtering water in 62 Florida cities, plus the Bahamas and the Gulf coast of Alabama.
The reefs are installed beneath docks, and that is part of their appeal, Timmerman said.
“They’re out of the way, in a dead area that doesn’t interfere with anything.”
Ironically, the mini-reefs are built of plastic, which has also been in the news and implicated in the degradation of water quality worldwide. But it’s not the plastic in the mini-reefs that does the work; it is merely the framework, providing surface area on which filter feeders grow in mass quantities.
“One of our mini-reefs cleanses 30,000 gallons of water a day,” Timmerman said. “Fish like snook and snapper feed by sight. They need clear water to be able to see their prey. When the reefs were put in under my dock, we had nothing but catfish and an occasional sheepshead. Now you see mangrove snapper, porkfish, ’cuda, grouper and shrimp.”
Do the math — 600 x 30,000 — and the Ocean Habitats systems are filtering 18 million gallons each day around Marco Island, although that is just a fraction of the total.
In addition to increasing water clarity, the mini-reefs remove nitrogen, phosphates and fecal coliform from the water, along with the micro-organism that causes red tide.
“The filter feeders need food — they eat karenia brevis,” Timmerman said.
Lisa McGarrity, a professor of chemistry at Florida Southwestern College, has been conducting research around the mini-reefs to test their efficacy.
“We do a number of parameters,” McGarrity said. “The dissolved oxygen levels around the habitats are markedly higher, 40 to 60 percent higher than in other areas. Turbidity levels, the clarity of the water, are noticeably better, and with clearer water, more plants grow,” which in turn help the water quality.
“Red tide blooms in a low-oxygen environment, and what oxygen is there, it robs. The conditions around these habitats are not conducive to red tide.”
There is nothing magic about the efficacy of the Ocean Habitats mini-reefs, said McGarrity, who emphasized she has no financial ties to the firm.
“It’s an absolutely simple concept — you’re just creating a mini ecosystem.”
Daniel Smith, Marco Island’s director of community affairs, said that their research was less than conclusive. According to their findings, “there were no measurable differences in water quality parameters a year after installation. However, site observations indicated that more fish were observed in the canal with marine habitats. Also, the water beneath a few of the docks with the habitats looked more clear than in the center of the canal.”
Timmerman said that while his system is effective, and could make a marked difference in the quality of all Marco’s miles of canals if sufficient mini-reefs were deployed, he has an even simpler solution that would largely repair local waterways — “ban fertilizer. The phosphates and nitrates in fertilizer are a huge culprit. My dream is to have the waters like they were 35 years ago.”
One additional real-world test to the Ocean Habitats system came a year ago when Hurricane Irma struck Marco Island.
“Out of hundreds of systems, the only one destroyed had a boat hoist fall on top of it,” he said.