Under the sea: Life is the bubbles in newly described deep-reef zone

Scientists have described a new zone in the Caribbean’s deep ocean, shining a light on a little-known world that’s home to numerous previously unidentified reef-fish species. The area in question lies at a depth of between 130 and 309 meters (427 and 1,014 feet). Scientists have proposed calling it the “rariphotic” (“scarce light”), in a recently published study in the journal Scientific Reports. The rariphotic joins two previously defined “faunal zones,” or layers of the ocean that host marine life: shallow areas and the mesophotic. The shallow zone refers to the band of ocean running from the surface down to a depth of about 40 meters (131 feet), where reef corals abound and SCUBA divers can normally go. The mesophotic (“middle light”) falls below this, down to 150 meters (492 feet), where some corals can still survive. Below these and the rariphotic lies the aphotic region, where there is effectively no light and relatively fewer marine species, including anglerfish, lanternfish, segmented worms and siphonophores. Classification of faunal zones above the aphotic based on analysis of fish assemblages at Curaçao. Representative coral and fish species are depicted for each zone. Image courtesy of the Smithsonian Tropical Research Institute. The classification of the rariphotic came about after surveys between 2011 and 2016 in the waters off southern Curaçao by marine scientists from the Smithsonian’s National Museum of Natural History. As warming surface waters sparked a decline in the health of shallow reefs, the scientists looked at the deep-reef ecosystems. This region, sometimes…

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