“What’s in the water is pretty disgusting. Our bays look like root beer right now,” Tomasco said. “It smells awful.”
Hurricane Ian, which initially hit Florida as a Category 4 storm, left its mark not only on the land but also on the water. The storm’s winds and excessive rain washed leaves, organic matter and pollutants into streams and bayous, signaling the beginning of serious environmental impacts that could occur. Researchers say degraded water quality can damage aquatic ecosystems for weeks, months or longer and pose a short-term human health hazard. Images and videos from space have captured the extent of the outflow.
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Since Ian’s landfall a week ago, Tomasco said he has received a dozen emails about the overflow from wastewater treatment plants along Florida’s west coast, from Palmetto to Fort Myers. Starting Tuesday, Orlando asked city residents to limit how often they flush toilets, take showers, wash dishes and do laundry because of overflowing drains.
Satellites show an increase in runoff of some of these materials, soils and overflowing rivers on land into the ocean, as shown in images comparing Oct. 1 with six days earlier, before Ian hit. Large discoloration in coastal waters indicates a change in water clarity or turbidity.
The brown water seen in the images contains a substance called tannins, which is dissolved organic matter that floats near the top of the water, making it look like tea or coffee. Some of the water’s turquoise color is likely due to organic matter and sediment washed to the surface by the hurricane.
“The fact that you can see it from a satellite is pretty impressive for the magnitude of freshwater coming out of the landscape,” said Todd Osborne, a biogeochemist at the University of Florida. “It’s all this excessive rain washing this material into the coastal waters … and the storm surge flooding the landscape, bringing up a lot of sediment and then going back into the ocean.”
He said the amount of runoff caused by Ian was “far greater than anything we’ve seen in the past”.
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Osborne said emptying freshwater streams into the ocean is a natural process and not necessarily harmful occurrence on a small scale. Organic materials can actually serve as food for microbial populations that are consumed by other animals higher up the food web.
But hurricanes can overload such systems. Too much floating organic matter can block sunlight from reaching plants deeper in the ocean, reducing their ability to produce food through photosynthesis and ultimately leading to the death of plant life. Microbes decomposing organic matter also increase activity, consuming large amounts of oxygen that would otherwise be available to others; such oxygen-deprived waters make it difficult for plants and fish to survive.
Researchers are particularly concerned about the region’s seagrasses, which require a lot of light and help support the local ecosystem. They help prevent erosion, maintain water clarity by trapping sediment and particles with their leaves, and provide food for animals and economically important fish. Poor water quality can wipe out parts of the local seagrass population.
“Time will tell how it shakes out, but depending on ocean currents and things, it’s a big concern from an environmental standpoint,” Osborne said. “The longer it takes to [the water] to settle will determine the impact it has on our nearshore seagrass habitats.”
The storm may also have washed pesticides and herbicides from farms and yards, as well as sewage products into water bodies, posing a health risk to people if exposed.
“Unless you have to be in the water, it’s not a good time to be there,” he said.
Such human-induced pollutants and nutrients coming off land can also trigger harmful algal blooms that are dangerous to animals and people, said marine and environmental scientist Hans Paerl. Harmful algal blooms, also known as red tides, are particularly prevalent along Florida’s west coast and can affect key fisheries important to the state’s economy.
“The story is not over when the storm is gone. It’s really just getting started from an ecological standpoint,” said Paerl, a professor at the University of North Carolina-Chapel Hill. “With all that runoff, we get a lot of nutrients coming out of the ground, especially nitrogen and phosphorus, which can increase harmful algal blooms.”
Paerl said that as climate change increases the amount of hurricane rainfall, he has also seen major changes in water quality and fish habitat in the North Carolina study area.
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Researchers aren’t sure how long the water quality problems will last. Flooding continues in parts of central Florida, raising river levels, creating more destruction and complicating cleanup efforts. Property losses are now estimated at more than $60 billion in Florida, according to an industry trade group.
Tomasco said Ian’s impact on water quality was among the worst in the state’s recent history, surpassing 2004’s Hurricane Charley, the last Category 4 storm to hit Florida’s west coast. After Charlie passed, almost in the same place as Ian, it took weeks for improvements in affected areas such as Charlotte Harbor, north of Fort Myers. The nearby Peace River was in bad conditions for two to three months.
“This is the worst hurricane impact on a large part of our state, worse than Charley,” Tomasco said of Ian. “That’s saying a lot because Charlie was pretty unwell for a long time.”