(Photo: livescience.com/Huw Griffiths)

Alex Bowser

Science/Tech Editor

akb6244@psu.edu

Geologists in search of sediment samples from the ocean floor in Antarctica drilled a half-mile-long hole into an Antarctic ice shelf known as the Filchner-Ronne Ice Shelf. Rather than gathering sediment samples, the scientists discovered a rock covered with a number of unknown lifeforms and organisms on the seafloor.

The scientists were based on the Filchner-Ronne Ice Shelf, the same ice shelf they had been drilling. The floating ice body is located in the southeastern Weddell Sea. They used hot water after spending hours shoveling snow to bore a narrow hole through the thick layer of ice. After, they lowered cameras into their makeshift holes to search the seafloor more than 1,000 feet below the bottom of the shelf.

In order to find their sediment samples, they needed to hit mud. Instead, they hit a rock, blocking their path to the seafloor’s mud. However, the team showed their footage to marine biogeographer, Dr. Huw Griffiths, with the British Antarctic Survey. Griffiths noted how the images caught were something quite unexpected.

Their images show a community of filter feeders including sponges never-before seen that were clinging to the rock. The significance of this discovery for scientists is the fact that “It’s a place where, essentially, we didn’t expect this kind of community to live at all,” according to Griffiths.

Previously, other animals discovered underneath Antarctica’s ice shelves prior to this discovery only included mobile animals, such as fish, jellyfish, crustaceans, and other invertebrates according to Griffiths. These creatures have the ability to actively move around their environment to gather food and find shelter.

Stationary animals, however, like these filter-feeding animals such as sponges and corals, remain in their fixed location, including the rock these scientists found them on. Rather than search for food, they survive on food that simply floats by. This includes phytoplankton and other algae that are microscopic in size but store an abundant amount of nutrients for marine ecosystems.

However, phytoplankton relies on sunlight for photosynthesis. Because this particular ecosystem lies underneath ice shelves and in deep-sea levels where sunlight isn’t as easy to see, the nearest source of sunrays is found at the edge of the shelf in open water, which is why many scientists have believed that sponges would only grow near the edges, and not any deeper.

The photos have proved us wrong, with several species of filter feeders found in the photos taken on the rock located over 160 miles from the edge of the ice shelf. On top of that, the sponges are roughly 370 to 930 miles from the nearest sources of phytoplankton. “This is showing us that life is more resilient and more robust than we ever could have expected, if it can put up with these conditions,” said Griffiths.

In addition, the ocean currents and patterns can cause phytoplankton to be swept farther from the ice shelf edges and loop back to the underside of the shelf. In short, Griffith notes that the food would “have to come the long way around to get to these animals.” Even with this, much of the phytoplankton might be eaten by other animals in the ecosystem before they make it to the stationary filter-feeders, or else they sink to the ocean floor, many dead by the time they get there.

“For me, that’s really exciting,” Griffiths said, “because these animals must be getting enough food from somewhere.” Of course, this raises questions about how much food these feeders need to survive, their metabolism rates, and where they get it if phytoplankton from the ice shelves aren’t enough, let alone if that’s where these organisms are getting their source of food from. After all, all the information provided has been assumed based on these photos taken.

Additional studies might present a greater challenge, however. “We’re going to have to develop technologies and things that can go and do that for us on their own,” according to Griffith. This is because no research vessel is currently able to get close enough to the seafloor. For now, scientists are already looking into using miniature underwater vehicles if possible, including robots that could fit through narrow boreholes.