A pair of strange discoveries this month shows that there is still plenty of mystery left at the bottom of the deepest parts of the world’s oceans – but not all of it is the good kind. First, scientists announced a grim but fascinating discovery when it was revealed that radioactive fallout was discovered at the bottom of the Mariana Trench, the deepest natural trench in the world. If nuclear fallout has managed to make it all the way down there, what does this mean for us surface dwellers?
The discovery of fallout in the Mariana Trench was made when marine biologists collected amphipods from the trench in order to analyze which, if any, radioactive isotopes might be present in the tiny creatures. Amphipods are diminutive crustaceans that feed on microscopic plankton, making them a perfect way to measure levels of ambient isotopes found in the world’s oceans. Prior to this most recent study, it was presumed that amphipods in the deepest parts of the world would be free from radioactive isotopes due to their isolation, yet scientists found high levels of carbon-14 anyway, similar in fact to levels of carbon-14 found on the ocean’s surface.
Above-ground nuclear tests conducted between 1955 and 1980 released dramatic levels of carbon-14 into the atmosphere and biosphere, making this isotope perfect for testing for radioactive fallout. This is the first time scientists have reported the presence of radioactive fallout in the Mariana Trench, and shows that radioactive material from nuclear tests can pass through the food chain to reach even the smallest, most remote creatures. It’s still unknown what effects this residual radiation could have on ecosystems in the long term. Can’t stop progress, though, am I right?
In less depressing ocean trench news, scientists with the Five Deeps Expedition may have discovered an entirely new species living in the deepest known part of the Indian Ocean. Five Deeps is the world’s first manned expedition to the deepest point in each of the five oceans and was exploring the Java Trench off the coast of Indonesia when it caught a strange creature on one of its submersible’s cameras. The team called the unidentified creature an “extraordinary gelatinous animal” which “does not resemble anything seen before.” See the footage of the creature for yourself.
Preliminary analysis suggests the animal may be an unknown type of sea squirt, but it’s difficult to tell from just photographic evidence, not to mention the fact that sea squirts are usually anchored to the sea floor. While it was initially believed the creature was a new jellyfish, Five Deeps chief scientist Alan Jamieson now believes it may be a specially-adapted sea squirt which is able to relocate itself in the event of seismic activity. “Trenches are quite seismic — and normally tunicates would be attached to the sea floor. And, now, if it’s quite a seismic environment, you run the risk of being buried,” Jamieson says, “so an adaptation to destructive environments is to raise yourself off the seafloor and in this case using this big long tentacle.”
We’ve only begun to peer into the world’s deepest oceans, and NOAA estimates only around 20% of the world’s oceans have been explored to date. Who knows what may lie in the darkness of the unfathomable depths below miles and miles of water?
Things much bigger and scarier than sea squirts and radioactive shrimp, I know that much.