Scientists Have Sailed Through the World's Biggest Ocean Desert Where Virtually No Life Exists

Deep in the South Pacific ocean there is a region almost four times bigger than the U.S. where virtually no complex life exists. This "ocean desert" is one of the most remote and least studied parts of Earth—yet the microbial communities that do exist there play a huge role in chemical cycles around the globe.

In a bid to better understand these microscopic lifeforms, a team of scientists spent six weeks sailing through the South Pacific Gyre—an ocean void covering an area greater than 14 million square miles.

The South Pacific Gyre is home to the oceanic pole of inaccessibility—the point on Earth that is farthest from any continent. It sits 1,670 miles from the nearest land, an uninhabited atoll to the north, Easter Island to the northeast and Antarctica to the south.

It is so remote and uninhabited, it is used as a spacecraft cemetery. It is also known to have a garbage patch, where plastic pollution has accumulated.

South Pacific Gyre
The South Pacific Gyre. Tim Ferdelman / Max Planck Institute for Marine Microbiology

There are a number of reasons why life struggles to exist there. Solar radiation is extremely high, having the UV Index label "extreme." This means anything exposed to the Sun is at risk of significant damage. The water is also particularly poor in nutrients—its distance from any land means there is a limited inward flow of dust particles—and phytoplankton, which forms the best of many aquatic food webs, is only found deep beneath the surface.

Finally, a gyre by definition is a massive system of rotating ocean currents—so the movement of the water means the area is largely isolated.

ocean gyres
Map showing five ocean gyres. NOAA

Despite this, satellite images show there is some life in the South Pacific Gyre—in the form of microscopic organisms.

Researchers from the Max Planck Institute for Marine Microbiology in Bremen, Germany spent six weeks sailing through the South Pacific Gyre to make an inventory of this microbial community. The team took water samples along a 4,350 stretch of the ocean desert. The samples were taken from depths between 65 feet and 3.1 miles—the sea floor. Using an onboard tool, the team was able to analyze the microbial organisms in the water instantly.

research ship path
The path of the research ship as it sailed through the South Pacific Gyre. modified from Google Earth / NASA

Findings showed that the South Pacific Gyre surface waters had about a third fewer cells than the gyres in the Atlantic, Bernhard Fuchs, one of the expedition leaders, said in a statement. "It was prob­ably the low­est cell num­bers ever meas­ured in oceanic sur­face wa­ters," he said, adding that they found similar microbe groups in their samples as in other nutrient poor regions of the ocean.

However, the surface water was also found to contain AE­GEAN-169, an organism that has only ever been discovered in deeper waters. This suggests it has adapted to the extreme solar irradiance. "It is def­in­itely something we will in­vest­ig­ate fur­ther," Greta Re­intjes, another of the research leaders, said.

Publishing their findings in the journal Ap­plied and En­vir­on­mental Mi­cro­bi­o­logy, the team says the analysis technique they developed will help drive the understanding of microbial communities—including those in extreme and remote regions like the South Pacific Gyre.