Tuesday, October 29, 2019

Red tide house of horrors in SW Florida, Halloween 2019

Last year we had an unprecedentedly bad run of harmful algae blooms in Florida, fueled by rampant nutrient pollution. (See my July 2018 post.) The most widespread of those HABs was a nightmarish Karenia brevis bloom that that affected every shore of the Florida peninsula but was worst in my area, Southwest Florida. After killing scores of dolphins, sea turtles, birds, and manatees, and literally tons of fish and invertebrates, the bloom finally dissipated over the winter. Following that, we had a relatively dry 2019, and a less than usual amount of regulated discharge from Lake Okeechobee to SW Florida's Caloosahatchee River. Folks crossed their fingers that the algae nightmare was gone. But marine biologists and other careful observers knew that nutrient pollution was still flooding into our waterways in the form of poorly managed agriculture, chemical-soaked urban/suburban landscapes, badly maintained stormwater ponds, overloaded sewage and septic systems, etc.

Though the coastal waters looked fairly clear for much of the spring and summer, if you stuck your head under the water you'd see the signs of trouble. The bottom was covered in piles of macroalgae (seaweed) and stringy billows of filamentous cyanobacteria. These bottom-dwelling algae were feasting on nutrients released from decaying organic matter, submarine groundwater discharge, and other sources. The thing about nutrients is that they never really go away- they just cycle through different forms as they slowly move through the environment. If the cycle is in balance, fine. But when we keep adding extra nutrients to the cycle, the excess grows cumulatively, year on year, and the harmful algae blooms grow stronger with each return. The only solution is major reduction in man-made nutrient loading (much less fertilizer, much better sewage treatment, etc.), combined with major increase in nutrient removal (through the protection and enhancement of vegetated habitats like wetlands that absorb nutrients and take them out of circulation).

The sadness of our recurring red tide situation was emphasized to me today by what I saw, smelled, and felt when doing fieldwork for an oyster restoration project in Naples Bay. Red tide concentrations were high enough in the bay to be clearly visible as a maroon haze in the water, and dead fish were floating belly-up everywhere. (High concentrations were also measured quantitatively in the area, as indicated on https://myfwc.com/research/redtide/statewide/) Yet, at the Naples City Dock marina there were no warning signs or anything posted, and patrons at "The Dock" restaurant were dining inches from the dead fish and toxic algae, apparently completely in the dark about its health risks. I didn't have much choice about getting in the water because it's my job as a marine biologist, but it seemed absurd to me that people would be paying to put themselves in that environment.

The immediate symptoms of exposure to red tide toxins are obvious. Exposure to the aerosolized toxins (e.g., from boat wakes or breaking waves) causes coughing, burning eyes, headaches, etc. Exposure to higher concentrations of toxins through contaminated seafood is worse, resulting in neurotoxic shellfish poisoning. However, what troubles me more is the less-known long term effects of red tide toxin exposure. Last year after the big blooms I got the longest-lasting and worst cough/bronchitis I've ever had. I would wake up in the middle of night every night with terrifying, suffocating coughing fits. I'm not just a crybaby hypochondriac who makes shit like this up, either. This really happened to me. Also, just about everybody I know who was around the water a lot last year had similar respiratory complaints. So I'm inclined to think that red tide exposure is a lot more dangerous than our state's cavalier attitude about posting warning signs and such leads residents and tourists to believe.

PS- Some particular actions that would reduce harmful algae blooms in Naples Bay, and which we should strongly lobby our leaders to take, are:
1) stricter and better-enforced fertilizer rules for both agriculture and urban/suburban environments,
2) better management of the canals and stormwater ponds that feed into Naples Bay; i.e., stop killing the beneficial wetland plants with mowing and poisoning,
3) pony up the cash for septic to sewer conversions and upgrade the capacity and treatment level of wastewater plants,
4) moratorium on new development in wetland and shoreline areas,
5) reintroduce "living shoreline" elements like mangroves and oysters along developed waterfronts to filter nutrients and algae out of the water,
6) re-route the drainage expansions that increased the watershed area of Naples Bay from 10 sq miles to 130 sq miles so that it's not overloaded with more freshwater and pollution than the ecosystem can handle.

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