Red tide is natural, blue-green algae blooms have major human cause

TCPalm has made it a crusade to advocate for the admirable cause of water quality in Florida. That is great and I fully concur with that goal. Unfortunately, the opinion section does not adequately explain the scientific differences between red tide and blue-green algae blooms. 

Gil Smart's Jan. 5 column, after his recent visit to Sanibel, implores Gov. Ron DeSantis to do the right thing to stop red tide outbreaks. A separate recent guest column about an environmental lawsuit about water quality was accompanied by the ubiquitous TCPalm photo of the fish killed by red tide.

Red tide is not caused by humans. 

If you don't believe me, read the article “Desert dust kills Florida fish" at Science.nasa.gov. NASA explains that iron from African dust storms and easterly trade winds combine with Trichodesmium bacteria in the Gulf that multiply and then bind nitrogen, leading to massive blooms of Karenia brevis (red tide). This explains the environmental history of red tide blooms in Spanish colonial times and, interestingly, our beautiful iron dust red sunsets. 

Blue-green algae, on the other hand, has a major man-made influence through excessive use of fertilizers and other nitrogen and phosphorus sources in stormwater runoff. Blue-green algae is the primary cause of the recurrent toxic algae blooms on the Treasure Coast.

Using the sensational "environmental catastrophe" of natural red tides for environmental political advocacy undermines the credibility of well-meaning advocates. We have enough scientific evidence with the man-made blue-green algae crisis; let's maintain our credibility by being scientifically accurate so that we can focus on the solutions that we can control.

Val Zudans, Vero Beach

Editor’s note: While red tide is a naturally occurring phenomenon, marine science experts — including those at Mote Marine Laboratory and the University of Florida’s Sea Grant program — have confirmed that coastal nutrient pollution can worsen an existing red tide bloom.