Home / Weather News /

Sargassum threatens: A blob larger than the US in Atlantic

06:00
16 March 2023

Sargassum threatens
A blob larger than the US in Atlantic

Sargassum covering a beach in Barbados in summer of 2022.Sargassum covering a beach in Barbados in summer of 2022. - © picture alliance

Seaweed often smells bad and creates inconveniences for the little ones trying to play on the sand. But is it harmful?

Florida beaches have been especially affected in recent years by an influx of seaweed, as the warmer waters and wind currents have brought more of this sargassum to the beaches.

Sargassum is a type of brown algae that takes a very long time to sink to the bottom of the sea and travels in large masses on the surface of the sea.

Many animals feed and live in the sargassum that often travels cross-continent. But once it loses buoyancy, the algae sinks to the sea floor, becoming a food source for other animals.

However there is currently a large mass of sargassum travelling west over the Atlantic. This mass is wider than the United States, covering over 8000 km. Scientists expect that if this sargassum reaches the Florida coast, it will be around June.

In recent weeks, Key West has experienced rafts of it. Southwest Florida is also at threat of receiving mass amounts, but from the Yucatan Peninsula, which has also experienced gigantic amounts of sargassum in recent years.

Is it harmful?

Sargassum floating on the sea is not harmful, but does become a nuisance piling up on the beach. As the algae rot however, it releases hydrogen sulphide, which is often harmful to our respiratory systems.

Large amounts of seaweed can also block waterways. During summer 2022, an unusually large amount of sargassum caused water shortages in St. Croix, which prompted a state of emergency for the U.S Virgin Islands.

Weather & Radar editorial team
More on the topic
Side-by-side weather maps showing UK and Ireland conditions. Left image: radar showing widespread rain bands spiralling across England, Wales, and Ireland with heavier rain near Cardiff and Liverpool; temperatures range from 16°C in Glasgow to 20°C in London and Cork. Right image: wind gust forecast highlighting strongest winds over southwest England and southern Ireland, with gusts up to 45 mph near Plymouth and 40 mph in Cardiff, Dublin, and Birmingham.
Monday 14 July 2025

Lots of wind and rain

Low pressure reaches the UK and Ireland
Flood water and weather radar showing heavy rain and thunderstorms over the southern US.
Thursday 10 July 2025

Downpours & flash floods

More severe weather in the USA
Snow-covered car and weather radar
Tuesday 8 July 2025

Winter feeling in summer

Fresh snow in the Alps
All weather news
This might also interest you
Two weather radars side-by-side, one showing sunny conditions over the UK and the other a temperature map showing widespread warmth.
Thursday 10 July 2025

Breakfast brief

Turning sunnier and warmer
Thursday 3 July 2025

Gusty too

Rainfall passes through the north
A temperature and weather radar of the UK and Ireland showing hot temperatures with clear, sunny skies.
Friday 11 July 2025

Breakfast brief

A hot and sunny outlook
All articles
Weather & Radar

www.weatherandradar.ie

facebooktwitteryouTubeContact uslinkList
Privacy Policy | Legal info | Accessibility statement