Some like it hot, but none more so that a collection of unusual creatures living on the mid-Atlantic Ocean floor. A volcanic vent three kilometres down belches fluids that reach a record 407 degrees, hot enough to melt lead. Yet shrimp, mussels and clams have learned to tolerate water close by that touches 80 degrees, a temperature sufficient to cook most marine species.
These extremophiles are the latest marine discoveries catalogued in the annual Census of Marine Life. Now in its sixth year, this international initiative pools information on studies of marine species, measuring what is there, detailing changes in species mix but also usually throwing up something new.
The something new can occasionally be something old, as in the case of the long-dead shrimp species that has apparently returned from the dead. Neoglyphea neocaledonica was thought to have died out 50 million years ago, but researchers found it alive and well and living on the side of a seamount in the coral Sea off northeastern Australia.
"Jurassic shrimp" was the nickname selected by its discoverers, who immediately drew parallels with the coelacanth finds off South Africa and Indonesia. This prehistoric fish was also thought long extinct until it was brought to the local fish market.
The census (www.coml.org) is a growing global network of researchers in more than 70 countries involved in a 10-year initiative to measure the diversity, distribution and abundance of marine life in the oceans.
It is associated with a variety of UN bodies and NGOs and other international organisations. It has its own scientific steering committee and helps to centralise data on life in the oceans.
The 2006 census involved 19 ocean expeditions and provided many inventories of nearshore biodiversity. It saw the use of tagging and satellites to follow 20 different species, including sharks, squid, sea lions and albatross, as they tracked the oceans.
Ireland has a tangential involvement in the work done by the census, explains Dr Ken Whelan, the Marine Institute's director of aquaculture and catchment management services. "We have a very strong association with them."
He is the current president of the North Atlantic Salmon Conservation Organisation (Nasco), which in turn supports a research programme called Salsea. Salsea seeks to understand why only a third of all the young salmon leaving European rivers for the north Atlantic eventually return to spawn.
Salsea was inspired by a census project called Post, which also looks at salmon losses, Whelan explains. Similar studies are now starting in Norway, and Salsea may join in a collaborative effort with Post using different technologies to measure salmon losses.
The Marine Institute is interested in taking part in census activities, Whelan says. It is all part of efforts to understand what lies beneath.
"We are really as ignorant in terms of the oceans as we are in space," he believes. "You wouldn't know what you would find in the deep oceans."
For much of the 1900s scientists believed the deep oceans were dead. "We now know there is a huge abundance of life in the deep oceans," says Whelan.
And, as the census shows, it can show up in the most unlikely places. Three census trips in the Southern Ocean found a community of marine animals living in profound darkness under 700m of ice and 200km from open ocean.
Fish counters tracking schools off New Jersey in the US recorded eight million fish swimming in a school the size of Manhattan Island.
Census deep-sea investigators found a new species of squid, Promachoteuthis sloani, that seems to be able to chew its food rather than swallowing it in pieces.
And the waters near Easter Island turned up a crab so unusual that it warranted a whole new family designation, Kiwaidae and a new genus, Kiwa. This white furry-looking animal is named after the mythological Polynesian goddess of shellfish which explains its full name, Kiwa hirsuta.
