The Sargassum invasion in the Caribbean and Gulf of Mexico

[eppur_se_muova]

1. DANGER: Stay away from sargassum rotting on the beach! It may release DEADLY hydrogen sulfide gas.

To clarify: the green algae Ulva, aka "sea lettuce" (it is edible) is well established as a source of H2S. But "golden tides" of Sargassum may be competing with Ulva as the temperature rises, favoring the latter, which is known to be deadly.

https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2024.1464511/full

https://phys.org/news/2009-08-horse-dies-france-reality-toxic.html

The video mentions "toxic gases", without specifying what they are, which is unfortunate, perhaps dangerously so. H2S stinks horribly, so normally it's hard to get close enough to get a fatal dosage, but its high toxicity is often underappreciated. Prolonged exposure can "numb" the olfactory bulb so that the smell becomes more tolerable, increasing the risk of lethal exposure. It can penetrate neoprene diving suits, and be absorbed through the skin, as well.