Only 0.001% of the ocean floor visually explored, study warns

Arab Times

08-05-2025

NEW YORK, May 8: A recent study has revealed that we have a far clearer view of Mars than we do of our own ocean floor, and the disparity is even greater than many might think.
The study, published in Science Advances, analyzed data from 43,681 deep-sea dives conducted since 1958, reaching a stunning conclusion: only 0.001% of the deep seafloor has been visually observed. This small percentage covers an area roughly the size of Rhode Island or about one-tenth the size of Belgium, across about 70% of the Earth's surface.
With the average depth of the ocean at 12,080 feet (3,682 meters), visual observation is incredibly challenging unless you have access to advanced deep-sea submersibles. According to the National Oceanic and Atmospheric Administration (NOAA), as of June 2024, 26.1% of the global seafloor has been mapped, but visual observations are much rarer.
'This small and biased sample is problematic when attempting to understand and manage the global ocean,' said Susan Poulton, a researcher at the Ocean Discovery League and co-author of the study, in an email to Gizmodo.
Scientists estimate that two-thirds of the ocean's species, excluding microorganisms, are still undiscovered. The vast uncharted seafloor offers immense opportunities for new research. However, the study highlights a significant bias in deep-sea exploration. Nearly two-thirds of all visual seafloor observations have occurred within 200 nautical miles of just three countries: the U.S., Japan, and New Zealand. Most of the research has been carried out by institutions from five countries: the U.S., Japan, New Zealand, France, and Germany.
"Imagine trying to tell the story of critical environments like the African savanna or the Amazon rainforest using only satellite imagery and DNA samples without ever seeing what lived there," Poulton said. "It wouldn't paint a very complete picture."
The study also found a bias towards shallow waters (less than 6,562 feet deep), even though nearly three-quarters of the seafloor lies deeper. Specific features like canyons and escarpments receive most of the attention, while vast undersea ridges and plains remain largely unexplored.
The research team stresses the need for a more thorough understanding of the deep sea. It plays an essential role in climate regulation, oxygen production, and medicine, but our limited visual assessment leaves us with a slim picture of this crucial biome. We are missing out on vast amounts of information about the creatures that inhabit these zones and how they contribute to global processes on Earth.
Some deep-sea research has been driven by commercial interests, particularly related to deep-sea mining in regions like the Clarion-Clipperton Zone. This has led to the discovery of hundreds of new species and new insights into oxygen production mechanisms. Without commercial interest, much of this research might have been overlooked.
The team's findings come in the wake of the Trump administration's push to fast-track deep-sea mining, which could put unstudied species at risk. Recent discoveries of thriving creatures beneath the seafloor have expanded our understanding of where life can exist, and deep-sea mining could disrupt these delicate ecosystems before science has the chance to fully understand them.
The study concludes that a global effort is needed to improve the exploration of the deep ocean. At the current pace, it could take more than 100,000 years to visually explore the entire seafloor. The team calls for a 'fundamental change in how we explore and study the global deep ocean.'
Currently, ocean policy, climate decisions, and biodiversity assessments are being made with an alarmingly small sample size of knowledge. The study urges innovation and collaboration to improve how we explore the most inaccessible parts of our planet, both for scientific discovery and the preservation of life on Earth.