During an expedition in April 2010 aboard the Royal Research Ship James Cook, scientists from Southampton University and its National Oceanography Centre used a robot submarine and HyBIS, a deep-diving vehicle, to locate and study volcanic vents at a depth of five kilometres in the Cayman Trough, an undersea trench south of the Cayman Islands. The vents shoot jets of copper-rich water at temperatures hotter than 450 ºC high into the ocean’s lower layers. Around the vents, the team discovered a new species of pale shrimp congregating in hordes around the six-metre tall mineral spires of the vents. They named it Rimicaris hybisae, after the deep-sea vehicle that they used to collect them. Instead of conventional eyes, the shrimp has a ‘light-sensing organ’ on its back, which may help it to navigate in the faint glow of deep-sea vents. Here, one of them describes its novel lifestyle:
Here in the Caribbean, at the bottom of the sea,
Your colour-sensing frontal eyes would be no use to me.
I’m Rimicaris hybisae, a shrimp who likes it hot;
I’ve got some useful optic gear, but ‘normal’ it is not!
My sunless evolution had to take a different tack:
To navigate my world I have an organ on my back
Which ‘sees’ black-body radiance around a deep-sea vent.
My life might not be bright like yours, but I am quite content.
I feed my tame bacteria just underneath my shell
With sulphuretted hydrogen (the stuff with bad-eggs smell)
That gushes from these vents all day. It’s symbiosis, see?
The H2S keeps them alive, and they give life to me.
Tube worms use symbiotic bacteria too: see Sightless symbiosis