Ar-Rehman

Sea without any shore on Earth because it doesn't touches any land

Forget the seaside, there’s one body of water on Earth which doesn’t touch a single coastline. The region, located in the North Atlantic Ocean is called the Sargasso Sea and it’s characterised by its unique boundaries. Rather than land, it’s defined by ocean currents, so there’s no Sargasso beach to hit. Not that you’d necessarily want to. The sea is blanketed in a foul-smelling brownish-yellow, seaweed (called Sargassum) and has become home to a nightmarish manmade island, dubbed the North Atlantic Garbage Patch. And yet, it remains a site of real ecological, historical and even cultural significance. A patch of calm water ringed by swift currents, sitting about 590 miles east of Florida yet never touching land. Known as the Sargasso Sea, sailors have crossed it for centuries, but few notice the border when they slip into glassy indigo waters. Those who linger find the surface scattered with golden-brown seaweed, Sargassum, named for the Portuguese word sargaço, a type of grape-like algae. The plants bob in slow motion, rolling gently like tumbleweeds on a prairie of water. The seaweed bursts with residents: shrimp the size of rice grains, neon juvenile fish, porcelain-white crabs and even young loggerhead turtles paddling their first miles of life. This floating cover grows so thick that early Spanish crews feared their wooden caravels would halt and “never again feel a breath of wind,” as Christopher Columbus wrote in 1492.

A special organisation set up to protect the exceptional sea hails it as a “haven of biodiversity” which plays a crucial role in the wider North Atlantic ecosystem. The Sargasso Sea Commission notes that endangered species of eels go to the sea to breed, while whales, most notably sperm and humpbacks, migrate through it, as do tuna and other types of fish. It is also key to supporting the life cycle of a number of threatened and endangered species, including the Porbeagle shark and several types of turtles. To borrow the words of renowned marine biologist Dr Sylvia Earle, it is a “golden floating rainforest”. Strip away the romance, and the Sargasso Sea looks like an 800-mile-wide nursery. Scientists call the drifting mats “habitat islands,” and for good reason. Hatchling turtles hide here until their shells harden. Porbeagle sharks cruise the shade below, while Bermuda storm-petrels skim the fringe, plucking shrimp in mid-dive. Researchers have counted more than 100 invertebrate species clinging to the weed, tiny colonists that hitch a ride for years before the mats eventually break apart. European and American eels begin their lives beneath these mats, no bigger than clear threads. They drift west or east on ocean currents, slip into rivers as far inland as Indiana, then, after decades in freshwater, swim back the entire 3,000-mile journey to spawn once and die. How they locate the same watery cradle baffles zoologists. Humpback whales also cross the sea each spring, and high-speed tuna streak through on their way to spawning grounds.

Sargassum is increasingly washing up on North American and Caribbean shores. And the sea isn’t just legendary in the eyes of oceanographers, it is the stuff of folklore, too. Christopher Columbus first documented encounters with its strange mats of Sargassum in his expedition diaries back in 1492. He wrote of his sailors’ fears that the seaweed would entangle them and drag them to the ocean floor, or that the windless calms (doldrums) that they faced in the Sargasso Sea might prevent them to returning to Spain. Such fears became part of the sea's lore for centuries, with its notoriety further boosted by its association with the infamous Bermuda Triangle. Longtime observers quickly learn that calm water masks heavy lifting. In summer, the surface warms to about 82–86 °F; in winter, it cools to roughly 64–68 °F. Those seasonal swings drive mixing which helps push warm, salty water northward and return cooler water south, a conveyor that steadies weather patterns on both sides of the Atlantic. The open water also pulls CO2 from the air, locking it into plankton shells which eventually snow to the seafloor. Only after two years of sampling did chemical oceanographer Nicholas Bates and colleagues at the Bermuda Institute of Ocean Sciences realize just how much heat the sea was absorbing. “The ocean is the warmest it’s been for ‘millions and millions of years,’” he said, warning that the trend could reshape “where it rains or where it doesn’t.”

The triangle, known for being an area where planes and ships would suddenly disappear for no reason, is located in the the southwest area of the Sargasso between Bermuda, Florida and Puerto Rico. The sea exists thanks to four currents: the North Atlantic Current to the north; the Canary Current to the east; the North Atlantic Equatorial Current to the south; and the Antilles Current to the west. These circular currents, called ocean gyres effectively trap the body of water within them, resulting in what Jules Verne described in ‘Twenty Thousand Leagues under the Sea’ as “a perfect lake in the open Atlantic.” The Sargasso Sea Commission, an intergovernmental body formed in 2014, calls the region a “haven of biodiversity” and urges countries to designate shipping lanes which skirt dense mats. Marine protected area status remains complicated; no nation owns the sea, and enforcement on the high seas is costly. Yet conservationists note that simple steps, rerouting tankers by 50 miles or banning longline fishing during peak turtle season, could preserve critical habitat without hampering trade. Policy moves slowly, while climate shifts quickly. Between stronger hurricanes and hotter summers, Sargassum now grows so prolifically in the Caribbean that beach resorts hire bulldozers to clear it. Excess weed sinks, rots and releases greenhouse gases, turning a carbon sink into a source. Paradoxically, the very organism that lends the sea its name may become a casualty of warming if rising acidity weakens its holdfasts.

The Sargasso is now under real threat from shipping, including underwater noise, damage to Sargassum mats and the release of chemicals, overfishing, pollution from floating debris and, of course, climate change. Because of the ocean gyres’s circulating motions, plastic swirls into the sea, joining the hideous garbage patch that has formed there. This gigantic memorial to humankind’s destructive ways is estimated to extend for hundreds of km's and to have a density of 200,000 pieces of rubbish/km squared. And things are only getting worse. Researchers have monitored these waters near Bermuda since 1954, recording temperature, salinity, dissolved oxygen and pH every month. Instruments show that winter water is slightly saltier than summer water, thanks to dry winds which whisk moisture off the surface, while rainfall each June and July freshens the mix. Since the 1980s, the average temperature has climbed roughly 1 °C, a small number that packs a punch. Warmer layers resist vertical mixing, starving deeper water of oxygen and hoarding nutrients which would normally rise to feed plankton blooms. Scientists have developed new metrics, such as “salinity anomaly” maps and basin-scale alkalinity indices, to compare one year to the next. Paired with drifting Argo floats and satellite color scans, the 60-year record has become a gold standard for tracking ocean acidification.

A new study found that the sea is warmer, saltier and more acidic than it has ever been since records began in 1954, and that this could have a serious and far-reaching impact on other ocean systems. The report’s lead author, chemical oceanographer Nicholas Bates, warned that the ocean is the warmest its been for “millions and millions of years”, which could lead to serious changes to local marine life and the global cycling of water, “where it rains or where it doesn’t.” Jules Verne once called the Sargasso “a perfect lake in the open Atlantic.” Today that lake collects trash from four converging currents: the North Atlantic Current, Canary Current, North Equatorial Current and Antilles Current. Those loops act like a mile-wide drain, funneling plastic bags, bottle caps and ghost fishing gear into a slowly rotating slick. One survey estimated roughly 200,000 pieces of debris per square km, about 518,000 pieces/square mile, spreading for several hundred miles. Underwater microphones pick up the growl of cargo vessels cutting straight through mats. Propellers shred the weed; paint chips flake from hulls, releasing copper and zinc. Noise can mask the low-frequency calls of sperm whales passing beneath. Meanwhile, floating nets entangle juvenile turtles exactly where they once found refuge.

If we lose the Sargasso Sea, rivers from Newfoundland to the Gulf of Mexico would send eels searching in vain for a birthplace erased by heat. Humpbacks might arrive in spring to find the larder bare. Storm tracks over Europe could drift, and the Atlantic might store even more of the planet’s excess heat, accelerating feedback loops we scarcely understand. People are now weighing a treaty to curb plastic discharge at sea and expand no-take zones around key migratory corridors. Shipping firms experiment with quieter propeller designs and biodegradable packing bands. None of these fixes alone will restore the Sargasso, but together they could keep the floating forest alive long enough for cooler heads, and cooler oceans, to prevail. For something that looks like an empty patch of blue on a map, the Sargasso Sea manages to knit continents together, nourish creatures halfway across the world, and offer humanity a running log of planetary change. The still water speaks softly, but its message rings clear: protect the calm, or brace for the storm that follows. Global warming may have reached a point from which there's potentially no return for quite a long time.