Sargassum is a type of floating brown seaweed found in the Atlantic Ocean. It forms large mats that drift with ocean currents and can wash up on beaches in significant amounts. While it plays an important role in marine ecosystems by providing shelter for fish and other sea life, excessive amounts can be a nuisance when they accumulate along coastlines.

Sargassum moves with ocean currents, primarily carried by the Gulf Stream and other Atlantic currents. It originates from the Sargasso Sea, a region in the Atlantic, and is pushed westward toward the Caribbean, Gulf of Mexico, and parts of the southeastern U.S. Large blooms can also be influenced by wind patterns and seasonal changes in ocean temperature.

Sargassum itself is not inherently harmful to humans, but when it decomposes, it releases hydrogen sulfide, which can produce a strong, unpleasant odor similar to rotten eggs. In high concentrations, hydrogen sulfide may cause mild respiratory irritation, especially for those with asthma or other breathing conditions.

Most people can touch sargassum without any issues. However, small marine organisms such as jellyfish larvae, known as sea lice, can sometimes be trapped in the seaweed. Contact with these organisms may cause minor skin irritation or itching.

Yes, but it may not be pleasant. While sargassum itself is not dangerous, large patches can make swimming difficult and uncomfortable. Additionally, small marine creatures within the seaweed may cause skin irritation. If sargassum is thick near the shore, it can also make water entry and exit more challenging.

Sargassum commonly affects coastal regions in:

• West Africa (including Ghana and Senegal)
• The Caribbean (including Mexico, the Dominican Republic, Jamaica, and Barbados)
• The Gulf (including Texas and Florida)
• Parts of South America (such as Brazil)

Yes, sargassum seaweed smells like rotten eggs when it rots. The smell comes from hydrogen sulfide gas that’s released as the seaweed decomposes.