Image of the Day
Fish at the Grounding Zone
Fish swimming over a bed of angular gravel at the grounding zone. The gravel and smaller sediments covering this seafloor fall out of the base of the melting ice sheet that is located here about 30 feet above the seafloor. WISSARD scientists observed in the several hours of taking video, a number of gravels and many smaller fragments falling down on the seafloor. This may be why benthic life (e.g. sea stars, sponges, urchins) has not established itself on this seafloor because they would be pelted by the rock fragments falling from above. However, fish are agile enough to avoid these projectiles as they take advantage of these seemingly desert-like feeding grounds. (Image credit: Deep-SCINI UNL-Andrill SMO).
Check out an interview with Chief Scientist Ross Powell on the CBC radio show Quirks and Quarks: Discovery: Fish Under Antarctic Ice.
See the Scientific American article Discovery: Fish Live Beneath Antarctica.
January 21st, 2015
WISSARD Scientists Announce Initial 2015 Findings from the Grounding Zone in National Science Foundation Press Release
Using a specially designed hot-water drill to cleanly bore through a half mile of ice, a National Science Foundation (NSF)-funded team of researchers has become the first ever to reach and sample the "grounding zone", where Antarctic ice, land and sea all converge. Data gathered from samples of sediment taken in the grounding zone will provide clues about the mechanics of ice sheets and their potential effects on sea-level rise.
Cameras sent down the drilling hole also revealed an unsuspected population of fish and invertebrates living beneath the ice sheet, the farthest south that fish have ever been found. The surprising discovery of fish in waters that are extremely cold (-2 Celsius, 28 degrees Fahrenheit) and perpetually dark poses new questions about the ability of life to thrive in extreme environments.
"I have been investigating these types of environments for much of my career, and although I knew it would be difficult, I had been wanting to access this system for years because of its scientific importance," said Ross Powell, a chief scientist with the Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project and a researcher at Northern Illinois University. "Findings such as these -- gaining an understanding of the ice sheet dynamics and its interaction with ocean and sediment, as well as establishing the structure of its ecosystem -- are especially rewarding. It's a big pay-off in delayed gratification."
The newest discoveries stem from the WISSARD project's investigation of the grounding zone of Whillans Ice Stream of the West Antarctic Ice Sheet (WAIS), roughly 850 kilometers (530 miles) from the edge of the Ross Ice Shelf in Antarctica's Ross Sea.
WISSARD is funded by NSF's Division of Polar Programs, which also provided the logistical support needed to succeed in the challenging Antarctic conditions. The Division manages the U.S. Antarctic Program, which coordinates all U.S. Scientific research on the continent.
Using a powerful hot-water drill developed and built by the University of Nebraska-Lincoln, researchers punched through nearly 740 meters (nearly 2,500 feet) of the Ross Ice Shelf on Jan. 8, 2015 (local time. U.S. researchers in Antarctica keep New Zealand time).
On Jan. 16, as more than 40 scientists, technicians and camp staff were working around-the-clock to collect as many samples and data as they could while the borehole remained open, the WISSARD team deployed a Remotely Operated Vehicle (ROV) called "Deep SCINI"--(Submersible Capable of under Ice Navigation and Imaging)--to explore about 400 square meters (4,300 square feet) of the marine cavity around the borehole.
The ROV was developed at University of Nebraska, Lincoln. The ROV discovered a variety of fish and invertebrates including numerous amphipods, or marine crustaceans, components of an ecosystem that may provide new insights into how creatures survive and even thrive in one of the world's most extreme environments.
"Finding fish, or any other type of life, under an ice shelf is by itself not novel," said John Priscu, a WISSARD chief scientist and a professor of land resources and environmental sciences at Montana State University, who has studied life in and under Antarctic ice for more than 30 years.
"However, our WISSARD data will establish for the first time sources of carbon and energy for higher trophic levels in this most southerly marine ecosystem. Our data will also provide important information on the connectivity between subglacial environments and ice-shelf productivity, allowing us to predict first responders to a warming climate," Priscu added.
After the initial Deep SCINI deployment, a package of oceanographic instruments, developed at Northern Illinois University, including a downward-looking camera, recorded data in the cavity over a tidal cycle and also observed many fish swimming by.
For additional information, downloadable images from the 2014-2015 season, or to contact the WISSARD project, look in our media guide, accessible at the top right-hand corner of the WISSARD homepage, above.
WISSARD Project Overview
Subglacial Aquatic Environments
Over the last several decades, by using ground penetrating radar and other remote sensing tools, scientists have discovered that under the massive Antarctic ice sheets there lies a vast hydrological system of liquid water. This water exists because geothermal heat flow from below, coupled with pressure, movement, and the insulating nature of the ice sheet above, is great enough to maintain some areas at the base of the ice sheet above the freezing point, even in the extreme cold of Antarctica. In topographic depressions there are hundreds of lakes, both large and small; some are isolated, but many are interconnected by water channels and large areas of saturated sediments, the water eventually running out into the Southern Ocean as the ice sheet becomes a floating ice shelf.
In order to explore one of these hydrological systems at the margin of the West Antarctic Ice Sheet, we have organized an interdisciplinary project to access the subglacial environment. The Whillans Ice Stream Subglacial Access Research Drilling project (WISSARD) is using a variety of tools and techniques to explore Subglacial Lake Whillans and the nearby grounding zone, on the southeastern edge of the Ross Sea. Radar and seismic equipment is used to profile the overlying ice sheet and the underlying water, sediments, and rock, while GPS stations accurately track ice movement.
This season our target is the grounding zone, where the massive West Antarctic Ice Sheet atop land meets the Ross Sea. This area is considered an important piece of the puzzle for our scientists interested in ice sheet dynamics. The work will help scientists assess the stability of the West Antarctic Ice Sheet, most of which sits below sea level. It is the last ice sheet on Earth resting in a deep marine basin and is the most likely player in any future, rapid sea-level rise. If the grounding zone is retreating or primed to retreat, rapid changes in ice behavior could follow over the next century. Work focused on microbial life, biogeochemical cycling, and surrounding geophysical surveys will also continue during the 2014-2015 season.
Our intentions are to have 8 days of science in the primary borehole at the Grounding Zone location mid-January. We will deploy all of the WISSARD tools during this period and recover sediment and water samples from the water cavity some 750 meters below the surface of the ice. We also hope to recover about 5 meters of basal ice cores at another borehole very near the primary hole. Image: Rachel Xidis/NIU.