Julia Guilbeau

@juliaguilb

Scientists discovered a new species of bone-eating worms during an alligator drop experiment in the Gulf of Mexico in February 2019.

Researchers at Louisiana Universities Marine Consortium (LUMCON), led by Craig McClain, Ph.D., sunk three alligators to the bottom of the Gulf of Mexico for the first time in history. They published the results of this study in January 2020, showing three different ways the alligators were eaten by marine life in the Gulf.

The worms were found burrowed in the bones from one of the alligator’s skeletons, slowly eating away and breaking down the carcass. The worm is a type of osedax, or bone-eating worm, which is typically found on the skeletons of whales. Scientists have never found these worms before in a reptilian skeleton, leading researchers to believe they are an entirely new species of osedax, according to River Dixon, a University of Louisiana at Lafayette Ph.D. student who worked on the project.

This project marked the first time osedax were found in the Gulf of Mexico, according to Clifton Nunnally, Ph.D., a researcher on the team.

Another surprising discovery from the experiment, according to researchers, was the disappearance of one of the three alligators, eight days after it was sunk. Nunnally said the researchers think a large deep-sea shark ripped the alligator from the weight used to sink it and devoured the alligator whole.

Giant isopods, bug-like sea creatures related to the roly-poly, also ripped apart another one of the alligators within 24 hours, according to Dixon.

The researchers used alligator drop experiment to see if reptiles such as alligators would be a viable food source, and if the animals living on the deep-sea floor would be able to tear into the thick skin of such a large reptile, according to Dixon.

Food is hard to come by on the pitch-black ocean floor forcing animals to eat most things that drift down to them. This area is also full of a huge amount of marine plants and animals, meaning animals do not get to be picky about what they are eating.

“Through many years of experiments, we know that the amount of carbon (i.e., food) that is supplied via flux [flow] from the surface is not enough to support the high numbers of animals on the seafloor.” said Dixon.

The scientists recently noticed growing reports of reptiles such as alligators and crocodiles moving into marine environments, making it plausible that such an animal may be used as an extra source of food once it died and drifted down to the bottom of the ocean, according to Dixon.

Marine reptiles existed back in the age of the dinosaurs, such as the ichthyosaur, a large marine reptile that ran the deep-seas in prehistoric times. The scientists wondered if there were still types of animals in the ocean that preferred meat from reptiles, like their ancestors would have, according to Nunnally.

Nunnally said the choice of using an alligator also fits with the culture of South Louisiana. The Louisiana Department of Wildlife and Fisheries provided the alligators used and taken from an overpopulation of alligators in the area, according to Nunnally

The experiment showed that other avenues of food, such as reptiles, are available for the deep-sea in a changing climate. It gave more insight into how the deep-sea works, helping scientists to make future predictions about what the bottom of the ocean may look like, according to Nunnally.

“It goes to show the deep-sea is good at utilizing any food source” Nunnally said.

The LUMCON scientists are continuing drop projects in the Gulf of Mexico and are currently conducting a wood drop experiment to learn more about the deep-sea food chain.