Cold as ice: Wikinews interviews Marymegan Daly on unusual new sea anemone

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Tuesday, January 21, 2014

In late 2010 a geological expedition to Antarctica drilled through the Ross Ice Shelf so they could send an ROV under it. What they found was unexpected: Sea anemones. In their thousands they were doing what no other species of sea anemone is known to do — they were living in the ice itself.

Edwardsiella andrillae and its habitat
Image: Daly et al.

Discovered by the ANDRILL [Antarctic Drilling] project, the team was so unprepared for biological discoveries they did not have suitable preservatives and the only chemicals available obliterated the creature's DNA. Nonetheless Marymegan Daly of Ohio State University confirmed the animals were a new species. Named Edwardsiella andrillae after the drilling project that found it, the anemone was finally described in a PLOS ONE paper last month.

ANDRILL lowered their cylindrical camera ROV down a freshly-bored 270m (890ft) hole, enabling it to reach seawater below the ice. The device was merely being tested ahead of its planned mission retrieving data on ocean currents and the sub-ice environment. Instead it found what ANDRILL director Frank Rack of the University of Nebraska–Lincoln, a co-author of the paper describing the find, called the "total serendipity" of "a whole new ecosystem that no one had ever seen before".

The discovery raises many questions. Burrowing sea anemones worm their way into substrates or use their tentacles to dig, but it's unclear how E. andrillae enters the hard ice. With only their tentacles protruding into the water from the underneath of the ice shelf questions also revolve around how the animals avoid freezing, how they reproduce, and how they cope with the continuously melting nature of their home. Their diet is also a mystery.

Cquote1.svg What fascinates me about sea anemones is that they're able to do things that seem impossible Cquote2.svg

—Marymegan Daly

E. andrillae is an opaque white, with an inner ring of eight tentacles and twelve-to-sixteen tentacles in an outer ring. The ROV's lights produced an orange glow from the creatures, although this may be produced by their food. It measures 16–20mm (0.6–0.8in) but when fully relaxed can extend to triple that.

Genetic analysis being impossible, Daly turned to dissection of the specimens but could find nothing out of the ordinary. Scientists hope to send a biological mission to explore the area under the massive ice sheet, which is in excess of 600 miles (970km) wide. The cameras also observed worms, fish that swim inverted as if the icy roof was the sea floor, crustaceans and a cylindrical creature that used appendages on its ends to move and to grab hold of the anemones.

NASA is providing funding to aid further research, owing to possible similarities between this icy realm and Europa, a moon of Jupiter. Biological research is planned for 2015. An application for funding to the U.S. National Science Foundation, which funds ANDRILL, is also pending.

The ANDRILL team almost failed to get any samples at all. Designed to examine the seafloor, the ROV had to be inverted to examine the roof of ice. Weather conditions prevented biological sampling equipment being delivered from McMurdo Station, but the scientists retrieved 20–30 anemones by using hot water to stun them before sucking them from their burrows with an improvised device fashioned from a coffee filter and a spare ROV thruster. Preserved on-site in ethanol, they were taken to McMurdo station where some were further preserved with formaldehyde.

This map shows the location of the Ross Ice Shelf in the Antarctic, and the two known localities for E. andrillae relative to McMurdo Station
Image: Daly et al.

Wikinews waves Left.pngWikinewsWikinews waves Right.png How did you come to be involved with this discovery?

Marymegan Daly: Frank Rack got in touch after they returned from Antarctica in hopes that I could help with an identification on the anemone.

Wikinews waves Left.pngWikinewsWikinews waves Right.png What was your first reaction upon learning there was an undiscovered ecosystem under the ice in the Ross Sea?

MD I was amazed and really excited. I think to say it was unexpected is inaccurate, because it implies that there was a well-founded expectation of something. The technology that Frank and his colleagues are using to explore the ice is so important because, given our lack of data, we have no reasonable expectation of what it should be like, or what it shouldn't be like.

Wikinews waves Left.pngWikinewsWikinews waves Right.png There's a return trip planned hopefully for 2015, with both biologists and ANDRILL geologists. Are you intending to go there yourself?

MD I would love to. But I am also happy to not go, as long as someone collects more animals on my behalf! What I want to do with the animals requires new material preserved in diverse ways, but it doesn't require me to be there. Although I am sure that being there would enhance my understanding of the animals and the system in which they live, and would help me formulate more and better questions about the anemones, ship time is expensive, especially in Antarctica, and if there are biologists whose contribution is predicated on being there, they should have priority to be there.

Wikinews waves Left.pngWikinewsWikinews waves Right.png These animals are shrouded in mystery. Some of the most intriguing questions are chemical; do they produce some kind of antifreeze, and is that orange glow in the ROV lights their own? Talk us through the difficulties encountered when trying to find answers with the specimens on hand.

MD The samples we have are small in terms of numbers and they are all preserved in formalin (a kind of formaldehyde solution). The formalin is great for preserving structures, but for anemones, it prevents study of DNA or of the chemistry of the body. This means we can't look at the issue you raise with these animals. What we could do, however, was to study anatomy and figure out what it is, so that when we have samples preserved for studying e.g., the genome, transcriptome, or metabolome, or conduct tests of the fluid in the burrows or in the animals themselves, we can make precise comparisons, and figure out what these animals have or do (metabolically or chemically) that lets them live where they live.
Daly explained how she obtained these images of the anemone's anatomy.
Image: Daly et al.
Just knowing a whole lot about a single species isn't very useful, even if that animal is as special as these clearly are — we need to know what about them is different and thus related to living in this strange way. The only way to get at what's different is to make comparisons with close relatives. We can start that side of the work now, anticipating having more beasts in the future.
In terms of their glow, I suspect that it's not theirs — although luminescence is common in anemone relatives, they don't usually make light themselves. They do make a host of florescent proteins, and these may interact with the light of the ROV to give that gorgeous glow.

Wikinews waves Left.pngWikinewsWikinews waves Right.png What analysis did you perform on the specimens and what equipment was used?

MD I used a dissecting scope to look at the animal's external anatomy and overall body organization (magnification of 60X). I embedded a few of the animals in wax and then cut them into very thin slices using a microtome, mounted the slices on microscope slides, stained the slices to enhance contrast, and then looked at those slides under a compound microscope (that's how I got the pictures of the muscles etc in the paper). I used that same compound scope to look at squashed bits of tissue to see the stinging capsules (=nematocysts).
I compared the things I saw under the 'scopes to what had been published on other species in this group. This step seems trivial, but it is really the most important part! By comparing my observations to what my colleagues and predecessors had found, I figured out what group it belongs to, and was able to determine that within that group, it was a new species.

Wikinews waves Left.pngWikinewsWikinews waves Right.png It was three years between recovery of specimens and final publication, why did it take so long?

MD You mean, how did we manage to make it all happen so quickly, right? :) It was about two years from when Frank sent me specimens to when we got the paper out. Some of that time was just lost time — I had other projects in the queue that I needed to finish. Once we figured out what it was, we played a lot of manuscript email tag, which can be challenging and time consuming given the differing schedules that folks keep in terms of travel, field work, etc. Manuscript review and processing took about four months.

Wikinews waves Left.pngWikinewsWikinews waves Right.png What sort of difficulties were posed by the unorthodox preservatives used, and what additional work might be possible on a specimen with intact DNA?

MD The preservation was not unorthodox — they followed best practices for anatomical preservation. Having DNA-suitable material will let us see whether there are new genes, or genes turned on in different ways and at different times that help explain how these animals burrow into hard ice and then survive in the cold. I am curious about the population structure of the "fields" of anemones — the group to which Edwardsiella andrillae belongs includes many species that reproduce asexually, and it's possible that the fields are "clones" produced asexually rather than the result of sexual reproduction. DNA is the only way to test this.

Wikinews waves Left.pngWikinewsWikinews waves Right.png Do you have any theories about the strategies employed to cope with the harsh environment of burrowing inside an ice shelf?

MD I think there must be some kind of antifreeze produced — the cells in contact with ice would otherwise freeze.

Wikinews waves Left.pngWikinewsWikinews waves Right.png How has such an apparently large population of clearly unusual sea anemones, not to mention the other creatures caught on camera, gone undetected for so long?

MD I think this reflects how difficult it is to get under the ice and to collect specimens. That being said, since the paper came out, I have been pointed towards two other reports that are probably records of these species: one from Japanese scientists who looked at footage from cameras attached to seals and one from Americans who dove under ice. In both of these cases, the anemone (if that's what they saw) was seen at a distance, and no specimens were collected. Without the animals in hand, or the capability of a ROV to get close up for pictures, it is hard to know what has been seen, and lacking a definitive ID, hard to have the finding appropriately indexed or contextualized.

Wikinews waves Left.pngWikinewsWikinews waves Right.png Would it be fair to say this suggests there may be other undiscovered species of sea anemone that burrow into hard substrates such as ice?

MD I hope so! What fascinates me about sea anemones is that they're able to do things that seem impossible given their seemingly limited toolkit. This finding certainly expands the realm of possible.


Sources

Wikinews
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