Since its discovery 520 years ago by Christopher Columbus, the Sargasso Sea has gotten more than its fair share of negative press.With ships’ crews fearing their vessels would get entangled in the massive mats of seaweed and sailors reporting days spent adrift in the windless doldrums not to mention tales of the Bermuda Triangle the Sargasso Sea was more the topic of legend and lore than scientific journals.But that’s all changing now that scientists are beginning to fully understand this dynamic open-ocean ecosystem and appreciate what Sylvia Earle called “the golden rainforest of the ocean”.As the only sea within the world’s ocean that is not bordered by land, the area of the Sargasso Sea is instead defined by ocean currents. The approximately 1,100 km wide and 3,200 km long sea is bordered on the west by the Gulf Stream, on the north by the North Atlantic Current, on the east by the Canary Current and on the south by the North Atlantic Equatorial Current.The Sargasso Sea takes its name from the brown seaweed, genus Sargassum, which is found floating on the surface in extensive lines (windrows) or mats that can stretch over multiple kilometers.Within the Sargasso Sea, the two most abundant species are Sargassum fluitans (broad-toothed gulfweed) and Sargassum natans (common gulfweed or spiny gulfweed). These species are unique among seaweeds because they are “holopelagic”, meaning they spend their entire life cycle free-floating in the water, never attaching to the bottom even for reproduction.Early oceanographers believed that Sargassum drifted into the Sargasso Sea on the Gulf Stream, carried from the Gulf of Mexico by the powerful ocean current. However, many scientists now believe S. fluitans and S. natans may have evolved within the clockwise gyre of the Sargasso Sea, developing specialised features that help them survive a life spent adrift, such as the spherical gas bladders on their stems that aid in buoyancy.For many years the Sargasso Sea was thought to be a relative “desert” in terms of productivity and biodiversity but, recently, oceanographers and marine biologists have begun to recognise the ecological importance of this region. The Sargasso Sea serves as crucial spawning grounds (eg, for the American and European eel, dolphinfish and marlin), as a nursery for juveniles (eg, for green and loggerhead sea turtles) and as feeding/hunting grounds (eg, for tuna and billfish, as well as shearwaters and other oceanic birds).The extensive and intricate mats of seaweed also provide habitat for a variety of organisms that are found only in this region (aka “endemic species”), including multiple species of fish, snails and crabs that are specially adapted to blend in with the Sargassum seaweed. Even humpback and sperm whales cross the Sargasso Sea during their annual migrations!Unfortunately, despite its somewhat remote location, the Sargasso Sea is not immune to environmental pressures and threats. The same currents that define its boundaries and form mats of Sargassum seaweed also collect trash and plastic that float on the ocean’s surface. The region is frequently traversed by commercial shipping operations and, as a result, suffers the consequences of oil spills and discharges of contaminated bilge/ballast water. And, like many other areas of the ocean, the Sargasso Sea is impacted by fishing practices that damage crucial habitat and result in high levels of by-catch.To help spread the word about the importance of the Sargasso Sea, here are a few interesting facts to share with others:1. When Sargassum washes up on the beach it gets buried over time and helps anchor the sand and prevent shoreline erosion.2. Many Bermudian farmers gather Sargassum from the beach, rinse it to remove the salts, and spread it over crops as fertilizer.3. Productivity within the Sargasso Sea is increased by numerous eddies, which upwell cold nutrient-rich water from the deep ocean.***To learn more about the Sargasso Sea and what is being done to protect this unique, biodiversity region visit the Sargasso Sea Alliance at www.sargassoalliance.org.