There are lots of weird and interesting species left to discover, and two of the richest sites will be the deep sea and Antarctica, both difficult of access. Last week the University of Lincoln, Nebraska news site released some cool findings of the ANDRILL team (Antarctic Drilling Program), which is headquartered on their campus. And they couldn’t be weirder: groups of sea anemones (animals in the phylum Cnidaria along with corals, jellyfish, and other groups) living upside down on the Ross Ice Shelf of Antarctica!
The discovery was actually published last December in PLOS ONE (reference and free download below). The scientists found the species by accident, using a 4.5-foot (1.4 m) robotic vehicle moving underneath the ice shelf at the location shown below, with the blue dots showing where they found the hanging anemones. They were just exploring and didn’t expect to see any new animals.
As the paper reports, the robot-mounted camera found two groups of anemones living about 6 km apart. The anemones have most of their bodies inside the ice, with the tentacles hanging below. They were described as a new species, Edardsiella andrillae (after the project). It’s one of only two species in the genus found in the southern hemisphere; the rest are in the north. And it’s the only species of sea anemone known to actually live in ice. Further, individuals hang upside down, which as far as I know is not done by any other anemone.
Here’s what they look like hanging from the ice. Imagine the surprise of the investigators when they saw this!:
Specimens were collected and preserved, and the paper describes their appearance and anatomy, but I won’t bore you with the details (the picture above is sufficient). They did see some other stuff, as reported in the news blurb (my emphasis):
“They had found a whole new ecosystem that no one had ever seen before,” Rack [Frank Rank, an author] said. “What started out as a engineering test of the remotely operated vehicle during its first deployment through a thick ice shelf turned into a significant and exciting biological discovery.”
In addition to the anemones, the scientists saw fish that routinely swam upside down, the ice shelf serving as the floor of their undersea world. They also saw polychaete worms, amphipods and a creature they dubbed “the eggroll,” a 4-inch-long, 1-inch-diameter, neutrally buoyant cylinder that seemed to swim using appendages at both ends of its body. It was observed bumping along the field of sea anemones under the ice and hanging on to them at times.
The anemones measured less than an inch long in their contracted state — though they get three to four times longer in their relaxed state, Daly said. Each features 20 to 24 tentacles, an inner ring of eight longer tentacles and an outer ring of 12 to 16 tentacles.
After using hot water to stun the creatures, the team used an improvised suction device to retrieve them from their burrows. They were then transported to McMurdo Station for preservation and further study.
Because the team wasn’t hunting for biological specimens, they were not equipped with the proper supplies to preserve them for DNA/RNA analyses, Rack said. The anemones were placed in ethanol at the drilling site and some were later preserved in formalin at McMurdo Station.
I’m curious as hell what “the eggroll” is. Any guesses?
This finding of the anemones, of course, raises a lot of questions:
1. How the hell do these things dig themselves into the ice? As the paper puts it more politely, “The means by which these animals burrow into the ice shelf is unclear, as are the physiological mechanisms that enable them to live in ice. Burrowing by sea anemones has been described as a process of serial expansion and deflation of the pedal disc or digging with the tentacles; neither of these strategies would seem possible in solid ice.”
2. What do they do when the shelf melts? It’s likely that some of these animals inhabit parts of the shelf that melt during the Antarctic summer. What do they do then?
3. How do they survive the bitter cold? The authors didn’t find any morphological features that suggested evolution for cold tolerance, but of course most of the adaptations would be biochemical and physiological.
4 What do they eat? The news release suggests plankton, which is logical, but we don’t yet know.
5. How do they reproduce? The authors are puzzeld about “the means by which Edwardsiella andreillae achieves it [sic] relatively large numbers.” Related species reproduce asexually by splitting transversely. The authors note that this could be tested genetically, for it predicts groups or clusters of genetically identical organisms. In contrast, sexual reproduction (also occurring in anemones), followed by migration of larvae and then colonization of the ice would create populations that are more genetically diverse.
I’m sure the authors (who are funded by the National Science Foundation) will get money to pursue these questions. And other scientists, as I’ve reported before, have found weird and undescribed species in Antarctica. At least on that continent—and in the neotropics—we’re in no danger of exhausting the supply of new species. But we are in danger of destroying them before they’re described, and that goes for both polar and neotropical groups.
Daly, M., F. Rack and R. Zook. 20013. Edwardsiella andrillae: a new species of sea anemone from Antarctic Ice. PLOS ONE, Published: December 11, 2013; DOI: 10.1371/journal.pone.0083476