The National Science Foundation-funded expedition found microbes, crustaceans and several kinds of strange fish living without sunlight in minus 2 degrees Celsius water
Using advanced underwater robotic vehicles and a specially designed hot-water drill, a team of more than 40 scientists with the Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project have uncovered a unique ecosystem of fish and invertebrates hidden nearly half a mile (740 meters) beneath the Antarctic’s Ross Ice Shelf. Living in perpetual darkness in a section of seawater only 10 meters deep, the animals are sealed between the ice shelf above and the seafloor below: a location considered so hostile that scientists with the WISSARD project expected only to find microbial life during their investigations.
“From a biological perspective, we got the first glimpse of life beneath the ice on the fifth largest continent on our planet—a continent that was previously thought to be nothing more than a benign body of ice” said study team member John Priscu, a professor of ecology at Montana State University.
Discovery of the aquatic animals stemmed from the WISSARD project’s ongoing investigation of the grounding zone – a location where Antarctic ice, land and sea all converge – of the Whillans Ice Stream, situated in the West Antarctic Ice Sheet roughly 530 miles (850 kilometers) from the edge of the Ross Ice Shelf in the Antarctica’s Ross Sea. The WISSARD project aims to advance climate change knowledge, mainly through the recovery of sediment and seawater samples from the grounding zone.
Earlier this month, the project used a specially designed hot water drill – consisting of a jet of hot water expelled from the end of a kilometre-long hose – to bore through a slab of glacial ice, roughly the size of the state of Texas, located at a point where the Whillans Ice Stream feeds into the Ross Ice Shelf. The drilling signalled the first direct observation of the grounding zone of a major Antarctic glacier, and once access to the grounding zone was stabilised, through submersible cameras, the team began gathering as many samples as possible while the borehole remained open.
Eight days after the team pierced the ice, the ‘Deep SCINI’ (Submersible Capable of under Ice Navigation and Imaging) remotely operated vehicle – designed, built and operated by the University of Nebraska-Lincoln – started exploration of a 400 square meter marine cavity around the borehole, unexpectedly detecting a variety of fish and invertebrates in the process.
The discovery of a thriving ecosystem beneath the 740 meter-thick ice shelf was a complete surprise as the WISSARD project scientists only expected to find microbial life due to the hostile and remote conditions. However, it is now hoped that these newly discovered aquatic animals can provide valuable new insights into how creatures survive and thrive in such harsh environments.
In total, the investigation spotted between 20 and 30 fish, many with big eyes – perhaps because they live in perpetual darkness – and others in shades of orange and black. However, the biggest – and most intriguing – fish had translucent skin, through which its internal organs were visible. Scientists also identified vertebrate and invertebrate life, as well as crustaceans and microbial life.
It is not yet known if any of these organisms represent entirely new species, however it is assumed that they would have biological adaptations in order to survive in such extreme environments, developing, for example, antifreeze glycoproteins which prevent their body fluids from freezing at subzero temperatures.
Whilst data, photographs and observations of the recently discovered organisms were gathered, other WISSARD researchers continued with the project’s main goal: attempting to better understanding of climate change. Knowing the importance of the grounding zone in the study of climate change, researchers lowered a string of sensors into another borehole melted through the ice.
These sensors will record an array of measurements including: temperatures in the ice and the water, the ebb and flow of tides and the pulsations of water from sub-glacial rivers flowing into the ocean. This data should reveal how much heat and mechanical stress is being delivered to the grounding zone of the Whillans Ice Stream, which is currently slowing down each year. The slow-down is believed to be part of a complex cycle of stops and starts that occur over hundreds of years in a number of glaciers that feed into this particular section of the Ross Ice Shelf.
— Antonio Sousa, Correspondent (Science)
Image Courtesy: jjunyent (https://www.flickr.com/