Red tide is responsible for 173 tons of dead fish and debris since Aug. 1.  

Image: Shutterstock

With the red tide moving offshore this week, we’re enjoying a respite from dead fish, stench and coughing spells, but people still have plenty of questions about Karenia brevis, the scientific name for those algae that periodically “bloom” in the Gulf, releasing neurotoxins that harm marine life and cause respiratory distress in humans.

We asked three scientists at Mote—Dr. Rich Pierce, Dr. Vincent Lovko and Dr. Tracy Fanara—to answer some of the questions you’ve been posting on our Facebook and Instagram. Here’s a quick summary.

Is it raining red tide?

No, red tide does not evaporate into the air and return to the earth in raindrops; in fact, rain can help break up the red tide toxins in the air and alleviate some of its effects.

Do the dying fish provide food for the algae and help them proliferate?

Scientists do believe this happens.

Is this the worst red tide outbreak ever?

Red tide has been occurring for centuries—early Spanish mariners reported encountering it near our coasts—so there’s no way of knowing the answer to that question. This does seem to be one of the most intense and longest episodes—although not (yet) as long as a 17-month-long spell that started at the end of 2004 and was even more devastating to marine life. It may be that social media, with its pictures of vast silver stretches of dead fish and close-ups of rotting dolphins, has amplified public awareness and anger.

Are the blue-green algae that have been flowing from Lake Okeechobee into the Caloosahatchee River ending up in the Gulf and providing food for the red tide algae, making the outbreak worse?

Scientists do not have data that measures how much of the blue-green algae is entering the Gulf. (And although the scientists wouldn’t come out and say it, we got the feeling they think this would be at best a minor contributor to worsening red tide.) We have had severe red tide outbreaks in the past when there was no problem with blue-green algae. We do know that more nutrients—from farms, yards, septic systems and other human activities—are pouring into our waterways, and it’s reasonable to suppose they’re worsening red tide outbreaks—and causing all sorts of other pollution and problems. Wherever they come from, those nutrients need to be addressed and curtailed.

Is red tide polluting our water supply?

No. The red tide is in saltwater, and we don’t use saltwater as our water supply. We use surface and groundwater. But freshwater algal blooms from the Great Lakes have showed up in drinking water in communities that get their water from the lakes.

Are people getting sicker from this outbreak than from previous ones?

Mote has heard reports of people getting flu-like symptoms that last for as long as a week, which is unusual. But then again, it could be that people were affected the same way in earlier outbreaks and never reported it. We’re getting better every year at collecting data, say the scientists, and although that can make it seem that a condition or problem is more prevalent, it may just have been under-reported in the past.

When will we able to stop red tide?

Not anytime soon—if ever. There have been a few small-scale studies aimed at controlling red tide, including one in which ozone successfully restored red-tide tainted water in a Boca Grande canal, but oceans are huge and incredibly complex systems, and red tide and other algal blooms occur constantly around the globe. More effort is going into improving our ability to forecast marine algal outbreaks and their intensity, but it’s complicated. Unlike weather, which follows the same physics and principles around the globe, every alga is different, with unique behavior and interactions with other marine creatures and conditions. Enormous amounts of research need to be done, and even with the increased interest and urgency sparked by Florida’s current algal outbreaks, funding is woefully inadequate.  

And finally, many of you asked how you can help. Mote has compiled a guide, from how to report distressed or dead sea creatures to advocating effectively for policies that will keep our water clean and natural. Here’s a link.

Filed under
Show Comments