Okay, I think we’ve endured enough information about the red tide problem along South Florida beaches. We’re fed up with reports of a blue-green algae caused by water releases from Lake Okeechobee. And now a new problem on coastal borders?
The Florida Fish and Wildlife Conservation Commission is reporting a new phenomenon that must be dealt with. Trichodesmium, which is also known as “brown tide” has developed offshore in Manatee County, which is just north of Sarasota. It is similar to red tide (Karenia brevis) but not the same species. This bacteria may be receiving its fuel from the Saharan dust that has provided us with such spectacular sunsets over the past few weeks.
Some scientists believe that this cyanobacteria affixes itself to nitrogen in the air and then drops to the water and this can help the red tide bloom to grow. Heaven help us if the two blooms do meet in our coastal waters.
Brown tide is nothing new. It has been documented for more than two hundred years. Each year at this time the winds from Africa’s west coast transport the desert dust to our area and this happens annually. The blooms can become large enough that they are visible from space. Even though brown tide may produce toxins, it has not been determined that they are harmful to marine animals and plants.
Now, if the brown tide merges with red tide, it becomes a source of food for red tide and can stimulate and prolong its growth. Since trichodesmium is more present at the water’s surface (it actually obtains its nitrogen from the air and then settles on the water) it has to die and begin sinking to a depth where the Karenia brevis thrives, about three feet below the surface. If and when this merger takes place, the dying brown tide becomes food and fuel for red tide.
Marco Island has been spared many of the issues experienced in points further north. Fish kills and plant life loss is catastrophic in Fort Myers, Sanibel, Englewood, Venice and Sarasota. As I write this (on August 24), I am receiving a text from my sister who has just arrived on a potential vacation at Siesta Key in Sarasota. Her text to me states that the dead fish along the beach are terrible, the stench in the air is intolerable, and she is leaving for Clearwater ASAP. Again, Marco has been very lucky to avoid such problems.
Just this week a manatee carcass was reported in our area… just one. As of this writing more than 550 manatee deaths have been documented throughout South Florida. Zero dolphin deaths are known in the Marco area while at least 10 have washed ashore in Lee and Sarasota counties. In Lee County alone nearly three tons of dead fish have been removed from their local beaches.
These are the “known” numbers. How many fish are dead in the water offshore? How many dolphins, manatees? One captain who fishes offshore referred to carcasses out there as a “floating graveyard.”
We see what occurs along the shoreline only. Satellite images indicate that red tide can be seen as far as thirty-five miles offshore in Lee County. How much devastation to our wildlife and ecosystems are really taking place?
This red tide bloom has been around since November of 2017. Brown tide could be a fuel to prolong red tide’s existence. The warm months ahead won’t help it go away either. Marco Island has, again, really dodged a bullet.
Apocalypse Marco… What if the winds changed direction and a consistent northwesterly breeze occurred, pushing these problems our way? What if the small amount of red tide we have in our area is fed by the brown tide? What if the Lake Okeechobee algae releases continued to push further south, affecting our marine life? The seagrass beds in Florida Bay are already decimated because of the change of saltwater/fresh water mix. What if that continues toward us?
What would Marco look like twenty years from now if these problems never went away? I’ve seen the disaster movies showing unpopulated major cities with vines growing on buildings and streets littered with unoccupied cars. Could that possibly happen in South Florida? Are these ideas too farfetched?
Let’s see. From Disney World on south our economy thrives on tourism. If people can’t enjoy the beach, they won’t come back. If they have to fish in waters that are now depleted, what’s the sense in coming here? If the hotels don’t have visitors, they go bankrupt or close their doors. If the Everglades issues are not corrected our fresh water supply is in jeopardy. If…
Have I made my point?
Bob is a Naturalist for the dolphin study team on the Dolphin Explorer, departing from Rose Marina. He is the author of two books and a member of Florida SEE (Society for Ethical Eco-tourism). Bob loves his wife very much!