Latest explorations of the sea around the Philippines have uncovered a slew of brand new marine life, of which more than 100 species are likely to be new to science.
In the seven-week survey, California Academy of Sciences researchers collected countless marine specimens, including rare and new species of colourful sea slugs, barnacles, and delicate heart urchins.
The expedition, funded by the US National Science Foundation, focused on the biologically diverse Verde Island Passage, nestled between the Philippine islands of Luzon and Mindoro.
While previous expeditions in 2011 and 2014 explored life in the western and northern portions of this narrow passage, the most recent trip took researchers to lesser-known field sites at its southern end.
â€œThe Philippines is jam-packed with diverse and threatened species â€¦ itâ€™s one of the most astounding regions of biodiversity on Earth,â€ says Dr Terry Gosliner, senior curator of invertebrate zoology at the academy and a principal investigator of the expedition.
The scientists snorkelled in sandy shallows, scanned steep, clear-water reefs, and dived to unimaginable depths, in deep-water â€œtwilight zoneâ€ regions never before seen by human eyes. The extensive fieldwork yielded thrilling results. The researchers discovered more than 40 new varieties of sea slugs or nudibranchs, many near the Philippine harbour of Puerto Galera.
The academyâ€™s highly-trained scientific diving team plunged to unbelievable depths to search for new species and collect live animals for an upcoming Twilight Zone aquarium exhibit. In a narrow band of mesophotic reefs, located between 30m and 166m deep, animals live in partial darkness, well beyond recreational diving limits yet above the deep trenches patrolled by submarines and ROVs.
Reaching those extreme depths requires divers to push the boundaries of both technology and the human body, using closed-circuit â€œrebreathersâ€ that extend the amount of time they can spend underwater. The rate of new-species discovery in the twilight zone can top 10 per hour, but scientists are typically afforded a scant 30 minutes in this light-starved region before beginning a multi-hour period of decompression on the way back to the surface.
This year, the team focused on bringing a selection of live fishes, corals, and jelly-like creatures safely to the surface, and back to the academyâ€™s public aquarium located in San Franciscoâ€™s Golden Gate Park.
â€œMore humans have visited the moon than have dived to the twilight zone,â€ says Steinhart Aquarium director Bart Shepherd. â€œMost of what we observe and collect is so special, and often new to science, that we invented a custom decompression chamber to safely transport fishes to the surface. Seeing these animals in-person will help the public learn more about why we need to explore and help protect the entire ocean, and not just what lives at the surface.â€
Twilight zone specimen highlights include 15 species of fishes as well as strange, multi-coloured ctenophores or â€œcomb jelliesâ€ collected from a depth of 90m. When hungry, the animal deploys long, sticky, hair-like tentacles into the surrounding waters to reel-in plankton, turning meal-time into an impressive display.
The discoveries will be described in the coming months as the scientists use DNA sequencing and other tools to analyse all specimens collected in the field, likely discovering even more new species in the process. â€“ California Academy of Sciences