Abyssal hydrothermal springs—Cryptic incubators for brooding octopus

Abstract

Does warmth from hydrothermal springs play a vital role in the biology and ecology of abyssal animals? Deep off central California, thousands of octopus ( Muusoctopus robustus ) migrate through cold dark waters to hydrothermal springs near an extinct volcano to mate, nest, and die, forming the largest known aggregation of octopus on Earth. Warmth from the springs plays a key role by raising metabolic rates, speeding embryonic development, and presumably increasing reproductive success; we show that brood times for females are ~1.8 years, far faster than expected for abyssal octopods. Using a high-resolution subsea mapping system, we created landscape-scale maps and image mosaics that reveal 6000 octopus in a 2.5-ha area. Because octopuses die after reproducing, hydrothermal springs indirectly provide a food supplement to the local energy budget. Although localized deep-sea heat sources may be essential to octopuses and other warm-tolerant species, most of these unique and often cryptic habitats remain undiscovered and unexplored.

The best of two worlds: reprojecting 2D image annotations onto 3D models

“…New technological developments such as LIDAR, multibeam scanning sonars or stereo camera are now significantly improving the speed and the accuracy of 3D reconstruction and the overall quality of 3D mapping, as well as providing a simultaneous mapping and imaging of the seafloor at centimetric scales ( Caress et al, 2018 ). These methods produce 3D models, bathymetry and orthophotomosaïcs that fully overlap, allowing the precise evaluation of species distribution in relation to topography ( Barry et al, 2023 ). But while this mapping system requires specialized and costly equipment, reprojection can be utilized directly on most ROV, making it cost-effective.…”