The Mysterious Sargassum of the Mysterious Sargasso

25 Oct The Mysterious Sargassum of the Mysterious Sargasso

In our #TallShipTuesday about the Sargasso Sea, we touched on the oases of Sargassum found in the open ocean. Sargassum is a fascinating seaweed. It is holopelagic, it spends its full life floating out at sea. The Sea itself is named for this seaweed, coming from the Portuguese word for grape, sargaço, because sailors thought that the little floaters looked like small grapes. 

Oases of Life

Sargassum clumps together in long lines or large mats which act as oases in a blue desert. This happens when the waves push the sargassum one way and the winds push it in another direction, Lines of Sargassum can stretch for miles. The mats clump together in a similar manner, and can be so massive it looks like land from afar. These clumps of Sargassum are home to all kinds of animals like Histrio histrio, the “Sargassum Fish,” crabs, shrimp, and many other animals. Hydroids and Bryozoans are very small and cling to the sides of the Sargassum where they munch on even smaller algae and zooplankton that float by.

The Types of Sargassum in the Sargasso

Several different types of these Sargassum call the Sargasso Sea home, and while these algae have their fair share of controversies, it has a beauty to it that is not sufficiently appreciated. 

There are three main types of Sargassum that are generally found floating in the Sargasso Sea: Sargassum fluitans III, Sargassum natans I, and Sargassum natans VIII. Scientists will look for little differences in each type. The figure above is a guide that one might use to help identify them. The leaves have a distinct shape in S. natans I, much thinner than the others. S. fluitans has thorns on the stems whereas the other two types do not. S. natans VIII has larger leaves than the other two. These different types of Sargassum often live in different parts of the Sargasso Sea.

It is no surprise that sailors in the age of sail (and even today) were weary of the Sargasso. But now that we know more about the sea and its important seaweed that floats out there, we are able to traverse the sea with little fear, and lots of wonder!