![]() ![]() Antarctic sponges have been known to live for thousands of years, so it’s possible that this is a truly ancient ecosystem. Alternatively, perhaps their parents lived on a rock hundreds of miles away-where the ice shelf ends and more typical marine ecosystems begin-and released their sperm and eggs to travel in the currents.īecause Griffiths and his colleagues don’t have specimens, they also can’t say how old these animals are. ![]() ![]() “Was it something very local, where they kind of hopped from local boulder to local boulder?” asks Griffiths. It’s also not clear how these stationary animals got there in the first place. “It's kind of a Goldilocks-type thing going on,” says Griffiths of the rock’s apparently fortuitous location, “where it's got just enough food coming in, and it's got nothing that wants to eat them-as far as we can tell-and it’s not getting buried by too much sediment.” (In the sediment surrounding the rock, the researchers also noticed ripples that are typically formed by currents, thus bolstering the theory that food is being carried here from afar.) It does appear that sedimentation around the rock isn’t very heavy, meaning the animals aren’t in danger of being buried. “Or are some of them kind of getting nutrients from each other? Or are there more mobile animals around somehow providing food for this community?” These are all questions only another expedition can answer. “Are they all eating the same food source?” asks Griffiths. The currents could also bring new animals to add to the population on the rock.Īnd Griffiths and his team also can’t yet say if mobile creatures like fish and crustaceans also live around the rock-the camera didn’t glimpse any-so it’s not clear if the sessile animals face some kind of predation. “And that inflow, even over hundreds of kilometers, is going to carry organic matter.” For our lifeforms stuck on that boulder, this would bring food. “There's going to be some inflow to replace that,” Mooi adds. “And these currents are actually the germ of many-if not almost all of-the current systems on the planet.”Īs that water pushes outward, something has to fill the void. “It sinks to the sea bottom and pushes water outward, radiating outward from the Antarctic,” says Mooi. As seawater cools in the region, it grows more dense. Given what scientists know about currents around Antarctica, this isn’t particularly far-fetched, says Rich Mooi, curator of invertebrate zoology and geology at the California Academy of Sciences, who has studied Antarctic sea life but wasn’t involved in this new work. To reach the animals on this Antarctic rock, food would have to travel as much as 133 times that distance-and it would have to do so by floating sideways. That’s an extraordinary distance, given that in the deepest part of the ocean, the Challenger Deep near Guam, marine snow produced at the surface has to fall 7 miles down to reach the seafloor. It may not be much, but it’s possible that enough organic material is riding these currents hundreds of miles to feed these creatures. Looking at charts of currents near the drill site, the researchers determined that there are productive regions between 390 and 930 miles away. The researchers think it’s likely that the drift of this marine snow has been flipped on its side, so that the food source is moving horizontally instead of vertically. At bottom left, you can see stalked animals. ![]()
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |