Tuesday, September 14, 2010

The Sargasso Sea: a famed Atlantic Ocean region is a gyre at risk

The Sargasso Sea - an area in the North Atlantic that is unique in several ways. It is a sea without shores, defined by aquatic borders made up of four open ocean currents: on the west by the Gulf Stream, to the north by the North Atlantic Current, on the east by the Canary Current, and on the south by the North Atlantic Equatorial Current. Collectively, this forms the North Atlantic Subtropical Gyre - a rotating pool of water some 700 miles wide and 2,000 miles long.

The other unique feature of the Sargasso Sea is its namesake. Within this large body of water resides Sargassum seaweed. Sargassum is a floating seaweed and as such provides an oceanic haven for a variety of sea creatures from juvenile fish, to predators to coral larvae. Over the centuries, vast mats of Sargassum were seen and documented by sailors. But there has been a steady decline in the acreage of this vital seaweed, which serves as a barometer of the ocean's health.

Mission Blue, the new research and expedition arm of Dr. Sylvia Earle's Deep Search Foundation, has designated the Sargasso Sea as one of the organization's Hope Spots - an ocean area that deserves attention and study because of what it says about the state of the planet's oceans.

Mission Blue recently visited the Sargasso Sea, near it's Bermuda epicenter, and from the organization's blog came these comments from Dr. Earle,
"No large mats of Sargassum but we snorkled around some small patches and had a great at sea rendezvous with the Bermuda Aquarium team who had a big tub of water on board their small boat and were able to show us a cross section of Sargassum's floating zoo -- some of the endemic crabs, shrimp and a miniature Sargassum fish as well as a little puffer, tiny jacks and other little critters."

Being a gyre, the Sargasso Sea is open to many of the same conditions that have grabbed attention in the Pacific Ocean with its Great Pacific Garbage Patch. Plastics, both in large floating pieces and in the degraded micro-particles, threaten the health of the Sargasso Sea and all of its inhabitants. Micro-particles of plastic form a deadly and sometimes toxic stew in the water which threatens everything from seabirds, turtles, pelagic fish (which are also at risk from swallowing larger pieces of plastic) all the way down to larval creatures that ingest the particles.

Disrupting the floating marine ecosystem and Sargassum seaweed that makes up the Sargasso Sea, through climate changes in surface temperature and pollution from plastics, puts this shoreless sea at risk of becoming a lifeless zone. Often written about in history as a thriving breeding ground and mysterious vast ocean forest floating across the surface of the water, the Sargasso Sea needs protection, lest it becomes just a footnote in our memories.

Visit the Mission Blue web site to learn more about the Sargasso Sea.

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