The Artful Amoeba

The Artful Amoeba

A Blog About the Weird Wonderfulness of Life on Earth

Cameron's Team Divulges Discoveries in Deepest Trenches on Earth


It's often said that we know less about the bottom of our own ocean than we do about the surface of Mars. The governments of the world, and our government in particular, seem presently much less than enthusiastic about exploring the oceans of our own planet than in exploring other planets (ocean research seems to have taken a particular hit in the last decade of Congressional budget cuts, although admittedly, all agencies have seen cutbacks). So film director and explorer James Cameron decided to build his own extreme deep sea sub and explore the deepest ocean trenches in the world himself.

In the last few years, he descended into several trenches -- including the Mariana last March, which at 36,000 feet, is the deepest in the world -- but remained pretty mum about what he found. Here's a PBS News Hour report on that descent:

There was also this raw and rather uninformative video of his dive released to the Associated Press:

He dropped a few more public hints about what he saw at the American Geophysical Union meeting in December, but as far as I know that is all. The only other manned mission to the the Mariana, in which Jacques Piccard and Don Walsh dropped to the bottom in the Bathyscaphe Trieste, took place in 1960, and the sediment stirred up by their vessel meant they were able to observe little about the life found there.

Apparently, at a rather obscure meeting in New Orleans this morning (the 2013 Aquatic Sciences Meeting of the Association for the Sciences of Limnology and Oceanography), Natalya Gallo, a grad student in charge of analyzing the 25 hours of footage Cameron collected while on the bottom of these trenches, presented some "preliminary findings". To me, this is a bit like televizing the images of the moon landing at an obscure planetary science conference. I don't know if any science journalists were there, but the description of what was found in the press release announcing the talk was exciting enough I wanted to share it with you here.

Early results of Gallo's analysis reveal a vibrant mix of organisms, different in each trench site. The Challenger Deep featured fields of giant single-cell amoebas called "xenophyophores," sea cucumbers, and enormous shrimp-like crustaceans called amphipods. The New Britain Trench featured hundreds of stunning stalked anemones growing on pillow lavas at the bottom of the trench, as well as a shallower seafloor community dominated by spoon worms, burrowing animals that create a rosette around them by licking organic matter off the surrounding sediment with a tongue-like proboscis. In contrast, Ulithi's seafloor ecosystem in the Pacific atolls featured high sponge and coral biodiversity.

Wait ... what? The spoon worms "create a rosette around them by licking organic matter off the surrounding sediment with a tongue-like proboscis"? Pictures or, even better, video please? Spoon worms, which don't get nearly the press coverage they deserve, appear to be annelids (like earthworms) that have lost their segmentation but otherwise preserve an internal annelid-like body plan. The proboscis is just weird, though. Known species seem to use it chiefly for filter feeding, so this "licking" behavior, whatever it is, seems to be something out of the ordinary. Here are some spoon worms photographed in a South Korean market:

Spoonworms at a market in Korea. A few have their probosci extended. Creative Commons J. Patrick Fischer. Click image for license and link.

Xenophyophores are even weirder. They appear to be somewhat slime mold-like organisms that consist of a giant bag or cytoplasmic network of cell nuclei that comb the seafloor ingesting food by engulfment (also called phagocytosis). Unlike terrestrial slime molds, their excretions and feces attract particles that are eventually cemented into odd-looking shells, or tests, that surround the organisms. They seem to have a thing for trenches. We know little about them because their tests are prone to crumbling when collected. Here's the one fuzzy photo I could find:

Xenophyophore in the Galapagos Rift. NOAA; public domain.

Here's another interesting finding mentioned in the press release:

Proximity to land also played a role in the makeup of the deep-sea environment. Deep in the New Britain Trench, located near Papua New Guinea, Gallo identified palm fronds, leaves, sticks, and coconuts-terrestrial materials known to influence seafloor ecosystems. The Challenger Deep and Ulithi, both more removed from terrestrial influence, were absent of such evidence. Gallo also spotted a dive weight in the Challenger Deep footage, likely used as ballast on another deep-submergence vehicle.

No where on Earth, it seems, can escape our footprint.

I hope someone was at this meeting to report on the talk. If not, I hope we hear more details about what Cameron found very soon!

The views expressed are those of the author and are not necessarily those of Scientific American.

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