快猫短视频

A deep-diving submersible has discovered 10 sea cucumber species emitting light for the first time in their natural habitat.

The observations were 鈥渢otally unexpected, like a spectacular movie,鈥� says at Nagoya University in Japan. In the control room on the research ship, 鈥渘obody could say anything except 鈥榳ow鈥�.鈥�

Sea cucumbers are animals in the same phylum as starfish, found on the ocean floor all over the world.

Confirming bioluminescence in deep-sea creatures is challenging. Researchers bring specimens onto a ship to examine them in complete darkness, but the difference in conditions on board can disrupt their glow.

鈥淚n the deep-sea environment, the pressure, temperature, light conditions, sound and chemical composition of the seawater: everything is different from the ship鈥檚 seawater tank,鈥� says Bessho-Uehara.

To see bioluminescence in the deep sea, Bessho-Uehara and his colleagues sent a remotely operated vehicle around 1000 metres down to the seafloor around Monterey Bay, California, with a highly sensitive camera and a robotic arm that could be controlled from the ship.

In their natural environment, light rippled down the animals from head to tail and back again like a wave 鈥� in contrast to bioluminescence seen in specimens on ships, which emit blue light all over their bodies.

快猫短视频s believe bioluminescence in these animals may be a defence mechanism. If a predator tries to attack the sea cucumber, it may emit light to attract other, fast-swimming predators, such as squid, sharks or fish, to prey on the assailant.

To be effective, this strategy needs transparent water, but human activities can make the sea cloudy. For example, deep-sea mining for minerals or drilling to extract oil and gas causes mud particles to be suspended through the water, preventing light penetration and disrupting organisms鈥� ability to communicate with light.

The new findings mean bioluminescence has now been observed in 26 of the 249 known sea cucumber species. Based on the evolutionary relationships between the species that glow, Bessho-Uehara and his colleagues estimate that there could be over 200 bioluminescent sea cucumber species on the seafloor.