Jellyfish Falls: An Underestimated Boon to Deep Sea Ecosystems

You may have heard of whale falls, but a new study of deep-sea ecosystems is arguing that it is actually jellyfish falls that are utterly essential to the complex and little-understood life of the deep sea.

A study recently published in the journal Proceedings of the Royal Society: Biological Sciences details how  massive "blooms" of jellyfish who float around the ocean's surface tend to die off en masse, causing the carcasses of semi-transparent invertebrates to fall to the deep depths of the ocean floor in waves at a time.

Even though these creatures are made up of primarily water, ecologists have stipulated in the past that these jellyfish falls did more harm than good on the ocean floor, as deep-sea animals might avoid dead jellyfish, leaving them to a slow degradation processes via microbial life. That, in turn, could be depleting oxygen at the seafloor, making life harder for fish and invertebrate scavengers, including commercially fished species.

However, the new study shows that this unsettling scenario was actually very far off the mark.

"We just had a hunch that dead jellyfish were important to deep-sea ecosystems in some way... We therefore decided to film what the fate of jellyfish carcasses were at the seafloor," lead author Andrew K. Sweetman, of the international Research Institute of Stavanger in Norway, explained in a statement.

According to the study, Sweetman and his team deployed several landers laden with deceased jellyfish to the deep ocean floor in the hopes of seeing how local ecosystems reacted to its arrival. (Scroll to read on...)

"When we later retrieved the landers and found no jellyfish attached to the bait plates we were pleasantly surprised," he added. "However, our surprise jumped to another level when we looked at the camera images and saw just how fast the jellyfish baits were consumed and the sheer number of scavengers that were consuming the baits. It just blew our minds."

According to the researchers, an unexpected wide variety of deep-sea creatures rushed these jellyfish falls just like they would with a nutrient-rich whale fall. With jellyfish falls occurring very frequently across the globe, the role of jellyfish material in deep-sea food webs might be seriously underestimated.