100 New Marine Species Discovered in Mysterious 'Twilight Zone'

More than 100 new species of marine animals have been discovered off the coast of the Philippines, in a previously unexplored portion of the Coral Triangle. Located on the southern end of the Verde Island Passage, these waters are considered to be the most biologically diverse in the world.

Researchers from the California Academy of Sciences visit the tropical reefs year after year to investigate the secrets of this underwater wonderland. In the latest seven-week venture, funded by the National Science Foundation and conducted this spring, their expedition took them from rocky shallows to depths reaching 150-500 feet deep, in a region known as the Twilight Zone.

Here, the light is scarce, and the depth has made these waters difficult for divers to access. Recreational diving is too shallow to penetrate these regions shrouded in darkness, while submersibles (such as ROVs and submarines) are designed to scan deeper waters.

“More people have walked on the surface of the moon, than have visited the Twilight Zone,” says Steven Bedard of Cal Academy.

But recent advances in diving technology allow scientists to unravel a part of the water column that has remained a mystery until now.

With the help of closed-circuit “rebreathers,” divers can extend their time at these extreme depths to 30 minutes. This specialized SCUBA equipment captures the unused oxygen from the carbon dioxide produced with each exhalation of breath, and recycles it back to the diver.

A second technological advance is the Cal Academy’s custom-designed decompression chamber for marine life. Divers can safely transport corals, fish, and comb-jellies of various sizes and colors from the depths to the surface.

Researchers are discovering about 10 new species per hour in the Coral Triangle’s Twilight Zone; because of the area’s immense biodiversity, that rate has yet to level out.

Among the countless specimens collected on the most recent expedition were vibrant sea slugs, barnacles, urchins, and 15 live fish from the Twilight Zone. In addition to the plethora of new species, researchers saw the first-ever living examples of animals whose existence had been known only through skeletons.

The heart urchin, for example, was discovered in 2014, and had been nicknamed Moby for its whale-like internal skeleton.

This spring divers came across a live heart urchin for the first time. With the knowledge they gained from this discovery, scientists were able to extrapolate a relationship between the oddly shaped urchin, and a fossil species that existed roughly 50 million years ago.

These “living fossils” enhance efforts to fill in researchers’ understanding of what makes up a sustainable environment for marine life.  By drawing comparisons between living organisms and their extinct relatives, scientists can start to answer questions about why certain species succeed in specific conditions, where others do not.

Despite the myriad threats spanning the globe, from archaic fishing habits to climate change, marine inhabitants of the Verde Island Passage continue to thrive. In part, the immense diversity there may be due to collaborative efforts made by more than a dozen institutions across the United States and the Philippines.

Rich Mooi, Curator of Invertebrate Zoology and Geology at the Cal Academy, says engaging and educating the local residents and Filipino agencies is a main priority of these expeditions. The science teams also work on education programs to connect fifth graders from remote villages with the unique biodiversity in their own back yard.

California residents can contribute to the well-being of biological gems, such as the Verde Island Passage, while never even leaving the continent.

“Our decisions on how we use natural resources like water and energy not only affect us in the Bay Area”, says Terry Gosliner, Senior Curator of Invertebrate Zoology at Cal Academy, “but has an impact on the health of coral reefs across the Pacific.”

Scientists do not yet know the full scope of what can be learned from the inhabitants of the Twilight Zone about why the ecosystem is nourishing to so many species. But they are getting closer to knowing where to focus protection efforts.

“We have to know what is there,” Mooi says, “and that is the primary purpose of these expeditions.”

He says Verde Island Passage is not formally recognized as a marine protected area, but it can act as one if humans preserve it for future generations.

The public will get a chance to see many of the new species discovered in the Twilight Zone in an exhibit opening in 2016 at the California Academy of Sciences, in San Francisco’s Golden Gate Park.