Biodiversity is Shrinking in the Sargasso Sea

Researchers have long been concerned that the rapid environmental changes that are occurring all over the world will eventually lead to stunningly decreased biodiversity. Now, a new study of the Sargasso Sea shows that, at least in some parts of the world, this may be already well underway.

About 3,000 miles long and 1,000 miles wide, the Sargasso Sea takes up nearly two-thirds of the North Atlantic Ocean. Biological surveys of this massive region conducted in the early 1970s showed that the sea boasted a mind-numbing variety of aquatic life forms, ranging from fish, to snails, to sea spiders.

The Sargasso's natural environment is best characterized by rafts of Sargassum seaweed - wide swaths of the white and browning sea plant that harbor a great variety of tiny animals.

However, according to a study recently published in the journal Marine Biology, a great deal of that biodiversity hiding among the Sargassum appears to have disappeared over the last few decades.

In a series of aquatic surveys conducted from the Lone Ranger, a 78-meter (255-foot) research vessel owned and operated by the Schmidt Ocean Institute, experts from the Montery Bay Aquarium Research Institute found that in 2011 and 2012 the Sargasso animal community was missing at least 13 species of animals, between worms, nudibranchs, crustaceans, and sea spiders.

Could it be that in the four decades it took researchers to return to these waters, those species died off or moved?

The researchers are quick to point out that due to changing sea currents, ocean conditions were much cooler in February 2011 than in later months - resulting in a large difference in animal communities just half-a-year apart. In this way, it may be that many of these species were simply missed.

However, they warn that that is a best-case-scenario.

"If this is a long-term decline [in biodiversity], then it is a very significant one," study author Crissy Huffard warned in a recent statement.

Huffard and her colleague Ken Smith hope to conduct a series of follow-up expeditions in the near future to analyze and compare survey results even further.