The farthest point from land on Earth lies in the central South Pacific Ocean, where the oceanic conditions are unique.

This remote area, known as the "Oceanic Pole of Inaccessibility" or "Point Nemo," is the center of the South Pacific Gyre (SPG).

Beyond being a final resting place for burnt-out satellites, what other mysteries lie beneath these distant waves?

For a long time, scientists paid little attention to this area. Despite covering 10% of the Earth's surface, this vast oceanic system was often considered a "desert" in terms of marine biology.

Nevertheless, life does inhabit this region, albeit sparsely and uniquely adapted to its challenges. Factors contributing to its sparse biological activity include extreme distance from land (thus lacking nutrient inputs from terrestrial sources), isolation due to swirling ocean currents, and exceptionally high levels of ultraviolet radiation.

Recent international research has provided unprecedented glimpses into the biological communities of these waters, despite the challenges posed by its extreme remoteness and vast expanse (37 million square kilometers).

Led by the Max Planck Institute of Marine Microbiology, a team conducted a six-week expedition aboard the German research vessel FS Sonne from December 2015 to January 2016, spanning 7,000 kilometers from Chile to New Zealand, passing through the South Pacific Gyre.

During this expedition, they utilized a newly developed analysis system to sample microbial populations in seawater ranging from 20 to 5000 meters deep in remote oceanic areas. This innovative system allowed researchers to sort and identify organic samples within just 35 hours.

"We were surprised to find that cell counts in surface waters of the South Pacific were a third lower than those in the Atlantic Gyre," remarked researcher Bernhard Fuchs in July 2019. "This may be the lowest cell count ever recorded in a marine surface area."

Among the microbial communities discovered by the team, 20 dominant bacterial branches were identified, including familiar organisms from other oceanic systems such as SAR11, SAR116, SAR86, and prasinophytes.

The distribution of these microbial communities largely depends on factors like depth, temperature, nutrient concentrations, and availability of sunlight. One particular microbial group identified as AEGEAN-169 was notably abundant in surface waters, whereas it had previously only been found at 500 meters depth in earlier studies.

"This suggests interesting potential adaptations of these microbes to ultra-oligotrophic waters and high solar radiation," noted microbiologist Greta Reintjes.

In conclusion, the sampling results confirm the South Pacific Gyre as a "uniquely ultra-oligotrophic habitat," where low nutrient availability restricts the survival of organisms adapted to "extreme physicochemical conditions" and specialized oligotrophic life forms. Thus, while the SPG retains its "desert" title for now, the scarcity of organisms in these remote and life-limited waters contributes to making it arguably the clearest ocean on Earth.

Future research will further reveal how these tiny organisms survive in ultra-oligotrophic environments, potentially offering new perspectives on Earth's life. Therefore, despite its remoteness and isolation, the South Pacific Gyre will continue to unravel unknown mysteries in marine biology.