Oceanographers exploring some of the most remote deep-sea hot springs have discovered one distinct biological zone teeming with life that nobody ever knew existed.
The discovery, located more than a mile down in the ocean just north of Antarctica, uncovered the most strikingly unique array of life forms found in decades, including thousands upon thousands of a particular crab species never seen before, as well new species of barnacle, anemone, snail and starfish.
The assembly of living creatures are clustered together in the hot, dark environment surrounding hydrothermal vents.
Several teams, led by the University of Oxford, University of Southampton and British Antarctic Survey, were part of the expedition that used a Remotely Operated Vehicle (ROV), called Isis, to explore the East Scotia Ridge in the Southern Ocean depths.
The biological hot zones were made up of hydrothermal vents, including ℠black smokers´ reaching temperatures of up to 382 degrees Celsius (719.6 F). The unique environment, devoid of sunlight, is rich in certain chemicals, the right kinds of chemicals, to support a delicate living ecosystem.
Scientists say the strangest thing, however, is what they didn´t find — tube worms, shrimp and mussels that have been found at the world´s other deep-sea hydrothermal vent communities.
Findings from the deep-sea expedition are highlighted in this week´s online issue of the journal PLoS Biology.
Highlights from the ROV dives include images of huge colonies of a new species of yeti crab clustered around the hydrothermal vents. Also, the ROV spotted numerous predatory sea-star creatures with seven arms crawling across fields of barnacles, and also an unidentified pale octopus.
“It wasn’t just one creature, virtually everything we saw was new to science,” Alex Rogers, professor zoology at the University of Oxford and lead author of the new report, told Eric Niiler of Discovery News (http://news.discovery.com/earth/antarctic-deep-sea-vent-creatures-010312.html). “It was a remarkable experience. You’re not quite sure if these things are mineral or biological structures. That’s a very unusual feeling to see all this stuff for the first time and saying I don’t understand what’s going on here.”
The discoveries were made during a January and February 2010 expedition to the Antarctic region. Rogers said it took nearly two years to get the findings published because there were so many undescribed species that his team had to send samples out to experts around the world for identification.
He recalled watching a small video screen onboard the British oceanographic vessel James Cook as the ROV descended more than 8,500 feet to the seafloor, transmitting back images of life from the biological hot zone.
“It´s probably the most exciting scientific cruise I’ve ever taken part in,” he told Niiler from his office in England. “The wonderful thing was that the discoveries just kept coming right through the trip. Seeing the images for the first time was absolutely breathtaking, just stunning.”
“It´s remarkable that we can be in the 21st century and still not know fundamental things about what lives on our planet,” said Cindy Van Dover, director of Duke University´s marine laboratory, who has been studying life at deep sea vents for 30 years but was not involved in the new discoveries. “This is really exciting because it keeps open the door for even more discovery down the road.”
But such an amazing discovery might also stir the debate for how such organisms got there in the first place.
“The Rogers paper fills in a piece of the bio-geographic puzzle for global vent faunas and raises new questions about evolutionary alliances and pathways to hydrothermal vents,” said Van Dover in an email to Discovery News.
“Their discovery of dense populations of crabs related to the yeti crab is especially intriguing. This family of crabs was discovered in 2005 at hot springs in the southeastern Pacific — there must be an evolutionary link between the two regions,” she said.
That means that the creatures living at underwater hot springs must be able to colonize other vents, even though the plumes are often short-lived, lasting only a few decades before the sea floor shifts and the hot springs disappear.
Another big question is whether the extremely cold water that circles Antarctica helps or hinders dispersal of the larvae of the strange life that thrive at the vents.
“Depending on the group of deep-sea organisms, the Southern Ocean can be an ecological dead end or a jumping-off point for colonizing other parts of the world,” said Rich Aronson, head of the department of biological sciences at the Florida Institute of Technology who studies Antarctic undersea life, but not part of the new research.
“This paper is a start to figuring out if one or the other scenario is the rule for vent faunas,” he said.
While most Antarctic marine animals lay eggs that include embryonic sec, the creatures found at the new deep sea hot springs do not. That is one key element in figuring out how they get from one vent to another, according to James McClintock, an evolutionary biologist at the University of Alabama, Birmingham.
“This would suggest that getting from one vent community to another is important, and having a small swimming feeding larvae is something that is being selected for,” McClintock said.
There have been numerous deep-sea hot springs teeming with life discovered throughout the world´s oceans since the first one in 1977. But this is the first time one has been discovered in polar waters.
McClintock says he expects there are more hidden places out there for scientists like him who are trying to understand the world’s animal and plant life. “The scientific community has gotten used to seeing the same assemblage of organisms at each of the vents“¦ Here you have a whole different suite of organisms. I would definitely say that the book is not written.”
These findings are yet more evidence of the precious diversity to be found throughout the world´s oceans,” said Rogers. “Everywhere we look, whether it is in the sunlit coral reefs of tropical waters or these Antarctic vents shrouded in eternal darkness, we find unique ecosystems that we need to understand and protect.”
The Southern Ocean, which surrounds Antarctica, has only recently been a focus of deep-sea exploration. Its waters can be treacherous, with storm swells regularly hitting 50 feet or more. Deep-sea vents in polar waters were first discovered in 1999 by Chris German, a geochemist at the Woods Hole Oceanographic Institution in Massachusetts. But he was unable to explore them for more than a decade, due to the difficult environment.
The discoveries were made as part of a consortium project with partners from the University of Oxford, University of Southampton, University of Bristol, Newcastle University, British Antarctic Survey, National Oceanography Centre, and Woods Hole Oceanographic Institution supported by the UK´s Natural Environment Research Council (NERC) and the US National Science Foundation (NSF).
On the Net:
- PLoS Biology Report (pdf)
- University of Oxford
- University of Southampton
- British Antarctic Survey
- University of Bristol
- Newcastle University
- National Oceanography Centre
- Woods Hole Oceanographic Institution
- Natural Environment Research Council (NERC)
- National Science Foundation (NSF)