Where?

 

While it is found in many tropical and temperate waters, Sargassum is most strongly associated with the Sargasso Sea. As there are no land boundaries to the sea, marine life is dependent on the ecosystems created by floating mats of Sargassum. The sea is bound on all four sides by ocean currents which deposit all manner of debris. Plastics have become embedded in the sargassum mats and are often consumed by the animals foraging there.

Within the past decade, Sargassum has become a big problem for Atlantic island and coastal communities. Starting in 2011, crippling blooms of the gulfweed have left beaches and waterways clogged, affecting tourism and wildlife. Changes in the environment due to climate change and nutrient runoff from agriculture have created ideal conditions for Sargassum to bloom. Sargassum muticim is an invasive species. Originally found in Japan, it has spread throughout the world's temperate waters, reeking havoc on local ecosystems. The floating Sargassum blocks sunlight from reaching the depths of the water, affecting native species. 

Sargassum thrives in warm water. As it floats above other species, it outcompetes other seaweeds for the sunlight it needs. Its reproduction through fragmentation give it an advantage: any harm that comes to a mat of sargassum can lead to the creation of new sargassum.

Sargassum distribution and Atlantic currents.