donaldmoreg
19.06.2021 3:11:44
Mats of free-floating sargassum, a common seaweed found in the Sargasso Sea, provide shelter and habitat to many animals. Image credit: University of Southern Mississippi Gulf Coast Research Laboratory.
See full version: What is the Sargasso Sea
Mats of free-floating sargassum, a common seaweed found in the Sargasso Sea, provide shelter and habitat to many animals. Image credit: University of Southern Mississippi Gulf Coast Research Laboratory.
Sargassum provides a home to an amazing variety of marine species. Turtles use sargassum mats as nurseries where hatchlings have food and shelter. Sargassum also provides essential habitat for shrimp, crab, fish, and other marine species that have adapted specifically to this floating algae. The Sargasso Sea is a spawning site for threatened and endangered eels, as well as white marlin, porbeagle shark, and dolphinfish. Humpback whales annually migrate through the Sargasso Sea. Commercial fish, such as tuna, and birds also migrate through the Sargasso Sea and depend on it for food.
[links]
Because of its stillness and seaweeds on the surface, the Sargasso Sea is a fascinating ECOSYSTEM. Marine biologists have called it a biological desert, largely devoid of plankton, a basic food supply for fish. It lacks the nutrients necessary to support large fishes. Even in the ocean desert, though, there is an intricate web of life that has adapted to existence among the weeds. The sea is abundant in smaller marine animals such as shrimps, small crabs, and octopi. Much of this marine life is directly dependent on the floating seaweed. Sargassum, a common frogfish, lives amid floating masses of sargassum seaweeds. These fish have developed an art of camouflage to the point where the fish is practically indistinguishable from surrounding seaweeds. The saline waters of the Sargasso are the breeding grounds of eels. Eels from thousands of miles away in North America and Europe swim here to mate and lay eggs. After the eel larva hatch, they make the long swim back. Sea birds are absent in this area, as their prey finds suitable hiding places among the weeds. The atmospheric temperature in this part of the Atlantic is higher—about 78 degrees F (26 degrees C), which helps in the process of evaporation. The higher salinity of Sargasso Sea is attributed to high temperature and greater evaporation and lack of mixture of fresh water by rivers or ice water.
THE SARGASSO SEA is located in the North ATLANTIC OCEAN. The area of the sea is found between 20 degrees N and 35 degrees N latitude and 30 degrees W and 75 degrees W longitude—the hump extending northward of BERMUDA. This is also known as the “horse latitudes.” The Sargasso Sea, relatively calm and motionless, is unique, as it has no boundaries or coastline. It is completely surrounded by waters of much faster ocean currents: the anti-cyclonic current system formed by the GULF STREAM, the Canaries current, and the equatorial current. On the west the boundary follows the coast of North America as far as 40 degrees N. The sea depth varies from 5,000 ft to 23,000 ft (1,500 to 7,000 m). It is a vast 2 million square mi (5.2 million square km) ellipse or ovalshaped mass of deep blue waters and spins in a clockwise direction. Sargasso Sea drifts and the changing ocean currents determine its location. The boundary shifts mainly from the force of the gulf stream. There is no similar phenomenon in other oceans.
Clear warm waters and large quantities of floating Sargasso or gulf weeds characterize the sea. The Portuguese word sargasso means “seaweed.” Sargassum is a brown algae with slender stalks, leaflike branches, and a glass bladder, which helps in supporting the stalks by serving as a float. It is normally attached to fixed objects on the bottom but often breaks loose and drifts into the Sargasso Sea. The algae that riddles its surface is actually a deceptive lush veneer to a stretch of ocean that is relatively devoid of life at deeper levels. The gulf weed is a floating plant without any roots. It is a type of LITTORAL flora that is isolated from the coast and has adapted itself in the new environment. The winding bands of water with floating weeds look like plankton rivers. The weeds occur in scattered masses of 100 ft (30.5 m) in diameter. The central part of the ocean possesses thickest weeds. It is estimated that the weed is spread over 2 million square mi (5.2 million square km). Perhaps the weed beds of the West Indies are the ultimate source of these weeds.
Christopher Columbus, who crossed it on his initial voyage in 1492, first mentioned the Sargasso Sea that encompasses the Bermuda islands. Because the sea is very calm with little wind, sailors since the time of Columbus mistakenly thought that seaweed itself is what trapped their ship. The mysteries of abandoned floating ships are associated with Sargasso Sea. There is no foundation to the belief that the amount and thickness of the weed can hinder a ship. The famed and feared Bermuda Triangle lies within the Sargasso Sea. The mystery of the Sargasso Sea was merely transposed later through the Bermuda Triangle. more
[links]
The Alliance Senior Science Advisory Committee included: here
Dr. David Freestone, Executive Director
Kate Killerlain Morrison, Deputy Executive Director
Dr. Samia Sarkis, Bermuda-based Programme Officer here
Acting Chair (June-August 2014): Kristina Gjerde, International Union for Conservation of Nature
Kevin Monkman, Permanent Secretary, Ministry of Health, Environment and Seniors, Government of Bermuda
Dr. David Freestone, SSA Executive Director more
· To use the process as an example of what can and cannot be delivered through existing institutions in areas beyond national jurisdiction.
Former Executive Committee members included Dr. Richard G. Rockefeller (Chair- January-June 2014); David E. Shaw (Chair- January 2011- December 2013). here
The movement of the major ocean gyres of the world helps drive thermohaline circulation (commonly known as the ‘ocean conveyor belt’), which circulates ocean water all over the planet. This circulation is crucial for the regulation of salinity, temperature and nutrient flow throughout the world’s oceans. here
While every other ocean of the world is defined, at least in part, by land boundaries, the Sargasso Sea is an exception to that rule, as it’s only defined by ocean currents. It’s bounded by the North Atlantic Current in the north, the North Atlantic Equatorial Current in the south, the Gulf Stream in the west and the Canary Current in the east. here
Sure, it lies ‘within’ an ocean, but it’s easily identifiable in the humongous water body, thanks to the characteristic brown Sargassum seaweed that floats on the surface and its relatively calm, blue waters. more
That record belongs to the Sargasso Sea.
The Sargasso sea lies within the North Atlantic ocean, surrounded by four currents that form an ocean gyre. For the uninitiated, an ocean gyre is a huge system of circulating ocean currents that are formed due to global wind patterns and the effects of Earth’s rotation (Coriolis effect). here
Excess sargassum can cause any number of problems. The algae floats when the mats are alive, but when they die, they sink. That can lead to suffocating blankets coming to rest atop delicate ecosystems such as coral reefs. Even worse, bacteria in decomposing sargassum suck oxygen out of the environment. Coral reefs in the Caribbean are struggling to survive as it is, and fundamental coral species have already been listed as endangered. more
Sargassum is like red wine or cologne. It can be very good in moderation. Sargassum is the umbrella term for a group of marine algae species—within a larger group called seaweed—that’s fundamental to the health of an entire region of the Atlantic and the many species who either live there or pass through. Sometimes, though, it explodes in growth, creating a continent-sized bloom that thoroughly freaks out multiple countries. These blooms have long happened and are perfectly acceptable if they happen rarely. They have not been happening rarely.
Of the many rivers that feed into parts of the ocean that eventually become part of the Great Atlantic Sargassum Belt, the Amazon is the biggest. And there’s a lot more stuff in the Amazon than there used to be, thanks to vastly increased logging, agriculture, and ranching along the river. Waste products from those industries make their way into the river and eventually into the ocean. Those products aren’t necessarily toxic. In some cases, they’re basically or literally fertilizer. Theoretically, at least, organic material spread on a soybean farm in the Brazilian interior could be feeding sargassum growth, which then blows over and ruins a tourist season—and livelihoods—in the resort towns of Mexico.
Over the past decade, we have not been experiencing normal circumstances. It is natural for sargassum to eventually blow westward and die, and end up on the beaches of the Caribbean, from South Florida to Aruba. This is part of sargassum’s life cycle, and Hu compares it to leaves on deciduous trees turning brown and falling in the autumn. But something has been changing in the past few years, and those dead and dying masses of sargassum have exploded in quantity. “When you have a very large quantity of sargassum, either on the beach or in coastal waters, then you have a problem,” says Hu. Hu’s team tracked this washed up sargassum to a strip they’re calling the Great Atlantic Sargassum Belt, a larger area than the Sea, stretching all the way from West Africa to the Caribbean and the Gulf of Mexico. Sargassum has always lived in these areas outside the Sargasso Sea, but never before in these quantities. Since 2011, it’s all become an essentially uninterrupted, massive strip—tens of millions of tons of seaweed that weren’t there before. more