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What’s brown, slimy and washing up
on beaches from Mexico to Africa?
Sargassum — a smelly seaweed
that’s been traversing the Atlantic Ocean in
massive clumps over the last few years. On
satellites, it looks like a single, monstrous
mass, but it appears
on beaches in
stinky, sticky
clusters.
The great Atlantic
Sargassum belt,
as scientists have
dubbed it, was
identified in a paper
published in July in
the journal Science.
Researchers first
spotted it via
European Space
Agency satellites in 2011, when the brown
algae was observed growing in massive
quantities. Almost every year since, the
seaweed has bloomed in the summer,deposited seeds in the winter and repeated
the cycle when temperatures started to
rise again. Though summer 2018 saw the
largest stretch of seaweed on record —
roughly 5,500 miles long — this year’s
mass wasn’t much smaller. And research
suggests the bloom isn’t going to die down
anytime soon.
What caused this stretch of seaweed to
get so big in the first place? Clues point to
fertilizer runoff from the Amazon River and
an upwelling of nutrients from deep waters
off the coast of West Africa. Fluctuating
ocean temperatures, salinity and nutrient
contents also may have played a role. But
the Science study ultimately left open the
question of cause, and its authors will
continue analyzing the seaweed in 2020.
While no simple answer can explain
the growth, scientists are calling the
sizable recent blooms the “new normal.”
As for your summer vacation, plan for the
possibility of lots and lots of Sargassum
when you’re sunbathing on the coast.Smells Like
Sargassum
BY JENNIFER WALTER
July 2019
The stinky seaweed Sargassum has been forming
a massive mat across the Atlantic — and washing
up on shores (top) — each summer since at least
- Researchers published their first full report
on the brown algae in July 2019, when the belt
was still going strong (above).