Toxins and the Tide
By Vicki Jackson
Coastal toxins, both natural and human-made, were in the spotlight at the Clearwater Marine Aquarium (CMA) last Thursday evening. With just a hint of optimism, facility Director of Education, Joe Malo, stated there has been improvement in Clearwater Harbor since the 1980's, and that the oil disaster has made people realize what's going on with our water.
According to Malo, a consequence of so many people living near the coast, plus the volume of tourists, has been elevated levels of waste from sewerage. While increased development diverts more water from the natural leaching process, increased run-off results in more oil, fertilizer, and pesticide infiltration. Contributing to the pollution are the pharmaceuticals, which are often expired products flushed intentionally by companies. Added to this is the toxic flow draining from the Mississippi River. He gave an example of how such toxins can end up in people, as when contaminated crab larvae is eaten by fish that ultimately becomes food for human consumption
Terrie Weeks, of the Sierra Club, addressed the environmental impact and named nutrient (especially nitrogen) pollution, as the common thread of coastal problems such as red tide, fish kills, and shellfish poisoning. Such pollution can be labeled either point source or non-source. She explained that the former originates primarily from industry and, as evidenced by the growth of area sea grass, is under pretty good control in Tampa Bay. The latter is a lot harder to control, as it cannot be pinpointed, coming largely from the use of fertilizers by homeowners. Excess nutrients are washed by the rain into the Gulf, where they feed the algae. According to Weeks, the fertilizer can stimulate overgrowth and may contribute to an algal bloom. A harmful algal bloom sucks oxygen out of the water as it dies, and blocks sunlight necessary for sea grass growth.
Dr. Leanne Flewelling, of the Fish and Wildlife Research Institute in St. Petersburg, asserted, "We need algae-we would be dead without it". She went on to explain how a complex combination of biology, chemistry (salinity and nutrients), and physics facilitates the formation of an algal bloom, which can grow quite large. Red tide is a generic term and all are not toxic, specifics depending on cause and location, and many questions have yet to be answered. But it's not something new, as documentation of mortality dates back to 1844. While the season for Florida red tide, a harmful bloom caused by the microscopic algae Karenia brevis, begins next month and continues through the end of the year, it can occur anytime.
The doctor noted that it doesn't have to be visible for it to be toxic for fish. The waters from Tampa Bay on down to Sanibel are at high-risk for the harmful bloom, as well as the Indian River Lagoon in particular. Large numbers of fish and dolphins have been poisoned, and shellfish, especially the bi-valves, have been contaminated due to Florida red tide. She noted that in the last forty years of monitoring, there has been no reported human deaths from eating legally harvested clams and oysters during an outbreak, and that lobster, crab, scallops and shrimp are usually okay. She credited careful regulation with assuring the safety of the seafood available in restaurants and grocery stores.
Dr. Flewelling described some of the typical symptoms that may be exhibited from exposure to red tide. In humans, that can be anything from a scratchy throat, a non-productive cough, and eye irritation, to difficulty breathing and acute respiratory distress. The toxin can be inhaled in the sea spray, or ingested from contaminated organisms. Animals are not immune, and birds, such as cormorants, pelicans, and tiny shorebirds have suffered from eating contaminated fish. It is thought that the toxins increase, as dead fish lie on the sand. She warned against walking dogs on the beach during red tide, as canines are susceptible too, and can experience seizures, salivation, paralysis, temporary blindness, and disorientation.
After answering numerous questions from the audience, Dr. Flewelling conceded, "There's a lot we don't know". As evidenced by queries regarding the oil spill, dispersants, and potential ramifications, citizens are concerned about their water. The current status of red tide and more information is available at http://research.myfwc.com.
The speaker from the Sierra Club referred to the new Pinellas County ordinance, which bans/restricts residential application of fertilizers containing nitrogen and phosphates, particularly during the rainy season June through September, as the key to reducing non-source pollution. She reflected on the success of Sarasota County, which enacted similar regulations about two years ago. She advised residents to save time and money by giving their lawns a vacation, as nitrogen is available in rain, reclaimed water, and grass clippings that should be left on the ground. Further information about helping to save Tampa Bay may be found at www.tbep.org.
The CMA Director of Education affirmed, "There are some things we can all do", as he distributed handouts with numerous recipes for making household cleaning products from common non-hazardous products.
Also freely offered, were indulgent refreshments. Throughout the evening, all present were invited to sample from a variety of hand-made chocolates, including nut brittles and chocolate-covered Twinkies, generously provided by Larry Butterfield, of Kilwin's Chocolates and Ice Cream, in John's Pass.
Part of the regular CMA "Making Waves" Evenings with Experts free speaker series, the August 19th presentation was the final one for this year. As a regular attendee of the informative third Thursday gatherings, Peg Post, of Clearwater, has been to all of them. She called the program wonderful, as she has "learned so much about everything that goes on here and out on the beach". The program will resume in 2011. CMA Board Vice Chair, John Draheim, explained that the aquarium would be closed to the public after September 10th, to allow filming of the movie "Dolphin Tale". The facility will continue to treat animals, in keeping with the non-profit's mission "dedicated to the rescue, rehabilitation, and release of marine life." To learn about current rescues and other events, visit their delightful website, www.SeeWinter.com.
Return to Current Edition