Here's why 6,000 octopuses like to be under the sea at an 'octopus garden'

[Mary Wilson]

August 23, 20232:02 PM ET
Nell Greenfieldboyce​

Off the coast of California is an unusual "octopus garden" — the largest congregation of deep-sea octopuses ever discovered on Earth, where over 6,000 octopuses huddle around an extinct underwater volcano in the black, cold ocean depths, almost two miles below the surface.

Most are brooding females that spend their days doing nothing but guarding nests full of eggs, a tedious task which can take nearly two years.It would take even longer if not for the warm water seeping from the seafloor that speeds upthe growth of their babies, according to new research that suggests this natural incubator is why octopuses gather there in such huge numbers. ...

https://www.npr.org/2023/08/23/1195...like-to-be-under-the-sea-at-an-octopus-garden
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[Mary Wilson]

23 Aug 2023

DOI: 10.1126/sciadv.adg3247​

JAMES P. BARRY, STEVEN Y. LITVIN, ANDREW DEVOGELAERE, DAVID W. CARESS, CHRIS F. LOVERA, AMANDA S. KAHN, ERICA J. BURTON, CHAD KING, JENNIFER B. PADUAN, [...], AND ERIC J. MARTIN +8 authors​

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.​

https://www.science.org/doi/10.1126/sciadv.adg3247