Four new species of deep-sea octopus have been discovered on underwater mountains around 3 kilometres down in the Pacific off Costa Rica, according to Schmidt Ocean Institute.
During expeditions in June and December 2023, researchers on the US non-profit organisation鈥檚 research vessel Falkor (too) found two low-temperature hydrothermal springs, two octopus nurseries and a skate nursery using a remotely operated vehicle named
Previous expeditions had shown octopus brooding areas near low-temperature springs, but finding these environments was challenging.
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Hot hydrothermal vents at a typical 350掳C are easy to spot, thanks to plumes of smoke billowing out of the seafloor. But the water temperature of the cooler springs is only about 10掳C higher than the seabed鈥檚 2掳C average, making them visible only by a slight diffraction of light.
鈥淚t looks like it鈥檚 shimmering,鈥� says expedition co-leader at the Bigelow Laboratory for Ocean Sciences in Maine, another non-profit.
It took multiple dives at various sites to find this subtle sign in the dark. 鈥淚t鈥檚 like walking in a forest you鈥檝e never been in before, with a flashlight, trying to find a hot spring,鈥� says Orcutt. 鈥淲e were kind of taking a gamble.鈥�
The four new species haven鈥檛 yet been formally described, but one has been named the Dorado octopus, after a rock known as El Dorado hill where it was found. A type of Muusoctopus, the females gather to brood their eggs in warmer water.
The researchers are confident the others are new species based on their appearance, says Orcutt. They appear to be solitary, which is more typical of deep-sea octopuses. 鈥淭hey don鈥檛 like to have their neighbours nearby,鈥� she says.
These insights into Costa Rica鈥檚 unique biodiversity could inform regional conservation policies. 鈥淚t鈥檚 hard to [protect deep-sea wildlife] when you don鈥檛 know it鈥檚 down there,鈥� says Orcutt.
These missions are also helping to inspire and develop local scientific talent through training for early career researchers in how to lead deep-sea expeditions, she says. The 310 specimens collected, which also included sea stars, brittle stars and sea cucumbers, will be housed at the University of Costa Rica鈥檚 Museum of Zoology rather than in the US where local researchers can鈥檛 easily access them.
With the deep sea facing many threats, including mining, more exploration is needed, says Orcutt: 鈥淲e鈥檙e really just scratching the surface.鈥�
