Sea urchins in the Caribbean began to
become sick
last year, losing their spines, dying off, and upsetting the balance of reef
ecosystems. In this maritime murder mystery, experts now believe they have
the culprit in their sights.
According to research published on Wednesday in the journal
Science Advances, a small single-celled parasite is to responsible for the severe
die-off.
Mya Breitbart, a marine microbiologist at the University of South Florida
and the study's author, declared that "the case is over."
These Diadema antillarum long-spined sea urchins are spiky, black, and may
be found on Caribbean reefs. According to Breitbart, they are essential
"lawnmowers" of the reef because they consume algae that develops on
corals.
But, beginning in January 2022, these creatures began exhibiting odd
symptoms (such as their sharp spines drooping and dropping off and their
suction-cup feet losing their grip) before passing away in great numbers all
across the Virgin Islands, Puerto Rico, and Florida.
It was déjà vu for marine experts because a similar die-off that hit the
area in the 1980s reduced sea urchin numbers by almost 98%.
It was an unsolved case. But this time, a global team of scientists sprung
into action, collecting samples from ill and healthy sea urchins around the
Caribbean to seek for genetic hints.
According to study author Ian Hewson, who studies marine illnesses at
Cornell University, they found no evidence of viruses or bacteria. But,
scientists did find evidence of ciliates, small single-celled creatures that
only appeared in ill urchins.
Although the majority of ciliates are harmless, this particular species has
been connected to past aquatic outbreaks, making it a prime suspect,
according to Hewson.
Scientists put the parasites in aquariums with healthy urchins raised in
captivity to observe how they would behave, hoping to catch the killer. 60%
of the 10 urchins that were tested against the small invertebrates perished
after exhibiting the identical symptoms as those seen in the wild by the
researchers.
According to Breitbart, it's probable that the die-off in the 1980s was
also brought on by this parasite.
Also, they haven't developed a cure for the sick urchins. Nonetheless,
scientists are optimistic that figuring out the cause of the die-offs may
benefit in reef conservation, particularly if they discover more about how
the parasites propagate, according to Breitbart.
Don Levitan, a marine biologist at Florida State University who was not
involved in the study but observes coral reefs, emphasized that the urchin
fatalities and other stressors had already altered the reefs.
Levitan remembered witnessing reefs in the U.S. Virgin Islands covered in
the prickly animals before the first sea urchin die-off. These reefs now
appear very different, engulfed in algae, afflicted by coral disease, and
overworked by the rising temperatures.
The Caribbean's coral reefs are in danger, according to Levitan. "Our
current situation differs from where it was 30, 40 years ago."
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