Researchers exploring Antarctica’s seafloor discovered a huge colony of icefish “about a third the size of London”.
The surprising discovery of around 60 million active nests was made by a team of biologists during routine data collection in the southern Weddell Sea of Antarctica.
Prior to this discovery, the largest colony found contained only 60 nests.
“We expected to see the normal Antarctic seafloor [mas] during the first four hours of our dive, we saw nothing but fish nests,” says Autun Purser, from the Alfred Wegener Institute for Polar and Marine Research in Germany, and lead author of the study published in Current Biology.
The ecosystem was found by accident using a photo and video recording system and deep-water habitat measurements.
The researchers were initially interested in the area because of a process called upwelling, in which wind and currents bring cold water to the surface, causing the water to be 2°C warmer than the surrounding area.
This colony of icefish is the largest found to date, stretching over 240 kilometers under the sea.
Colony size suggests that the entire Weddell Sea ecosystem is influenced by these nests.
“It is extremely likely that seals are feeding on these fish nests,” says Purser.
Purser says the discovery showed that there are still major gaps in understanding how deep-sea ecosystems work.
“The deep seas are not deserts, they are really abundant with life”, he says, adding that “the fact that there are ecosystems so large that we didn’t know about it shows how, probably, there is still to be discovered.”
The ecosystem will be monitored over the next two years to try to determine how it works and how it interacts with other ecosystems.
The researchers plan to return to the region in April 2022, to survey the surrounding waters and see if the fish breed again in the same nests.