Anemones in the Ice Shelf? It’s more likely than you think.
Often when places are thought to be completely derelict and inhospitable, a new species is stumbled upon proving the theory wrong. The Antarctic Ice Shelf is no different. In 2010 the Antarctic Geological Drilling Program (ANDRILL) was dispatched to the Ross Ice Shelf to survey the ocean currents to model the behaviour of a drill sting. On the bottom of the ice shelf, some 270 metres deep, one of the researchers commented that the ice looked “fuzzy” prompting an investigation of the bottom of the ice shelf. What was discovered shocked the entire crew, as they found tens of thousands of anemones sticking out of the sea ice in to the water. Dozens of studies and expeditions have been done in the Ross Sea however up until now; no one has ever looked up, leaving this ecosystem undiscovered up till now.
The anemone, named Edwardseilla andrillae was named after the ANDRILL expedition and was found anchored to the underside of the sea ice. Although the team were not prepared to collect biological samples, the anemones were stunned with warm water before being collected and stored in ethanol or formalin for further study. The anatomy of the anemones was preserved but unfortunately the DNA was damaged during storage.
E. andrillae is less than an inch long when contracted but was found to expand to three or four times that length when relaxed. It has twenty to twenty-four tentacles arranged in an inner row of eight surrounded by sixteen and appears as an opaque white, glowing orange under the ROVs lights. It is unknown whether this was due to the animal itself or possibly due to its diet.
E. andrillae, although not the only species of anemone found in Antarctica, is the only known species to attach itself to ice, living upside down, with most species being found anchored to either hard or soft substrates below the anchor ice. Anemones burrow in to sediment by inching their bodies in or by digging with their tentacles. However these conventional methods of burrowing employed by most anemones do not seem to be feasible in the hard ice shelves. In fact it is not known how they burrow in to the bottom of the ice shelf, especially whilst the surface is actively melting. It is also unknown how they reproduce or withstand the freezing temperatures. It is thought that this species is a filter feeder feeding on plankton in the water column, however even this is not known for certain. One scientist suggested that they may secrete chemicals to dissolve the ice, however at this point there is no research or knowledge that would support such a claim.
E. andrillae is distinguished from other species of its genus by the number of tentacles and the size and distribution of its cnidae. The family Edwardsiidae contains burrowing anemones reported from habitats ranging from the deepest trenches to hypersaline and hyposaline coastal estuaries. E. andrillae is the first species not from coastal waters. And as of 2014 E. andrillae has only been seen under the Ross Ice Shelf.
Samples of E. andrillae have been dissected, however it has revealed little. There are no morphological adaptations that would allow them to burrow in to the sea ice or survive the freezing temperatures. In fact the morphology does not suggest any adaptations to the unusual habitat it thrives in. Instead it appears they have the same anatomy as any other anemone, despite being found to be significantly larger than anemones from brine channels.
Further in-depth study is proposed as this discovery has interesting implications for the search for extra-terrestrial life on Europa, Jupiter’s icy moon. Europa has long been considered to be the most probable source of life on other planets in our solar system and the ice shelves on Earth are a good analogue for the liquid global ocean below its icy crust. There are places with complete darkness, very thick ice and the chemistry and properties of the ice are strongly influenced by the ocean. This newly discovered ecosystem could hint at the type of life that might plausibly exist on the subsurface oceans of Europa. Unfortunately due to the inaccessibility of the environment and limited access to new technology, most of the Antarctic remains unexplored and many ecosystems, much like this one, remain undiscovered.
This species was not the only new discovery, a species of fish that swam upside down using the bottom of the ice as its “ground” was discovered as well as species of polychaetes, amphipods and an unknown creature that has been named the “eggroll”. This unique habitat has raised questions about the biology, physiology and life history of the anemone that as of this moment, we simply do not have the information to answer. Without a doubt E. andrillae can definitively be classed as an extreme marine organism.