Deep-sea sponges are not known for their mobility. Finally, they lack muscles, nervous system and organs. And forget about fins or feet to travel the Arctic bottom.
But new research suggests that these ancient life forms can and can be bypassed – and much more than marine biologists believed. Studying hundreds of photographs and videos of Arctic sponges, scientists from the German Max Planck Institute for Marine Microbiology have discovered a huge network of trails several meters long in the movement of these creatures.
“Sponges are one of the most primitive forms of animal life,” said Dr. Teresa Morganti, who led the study published Monday in the journal Current Biology. “In the beginning, we were very skeptical. We thought, ‘That’s not possible. The sponges cannot move. ‘”
For the study, dr. Morganti and her colleagues examined underwater images of Langseth Ridge, a marine mountain range not far from the North Pole located nearly a mile below the permanently ice-covered surface of the water. Despite their initial skepticism, they found evidence that wild sponges not only move around their cold habitat, but also change direction and even thrive uphill.
“They’re more active than we think they are,” said Rachel Downey, a deep-sea sponge expert from the Australian National University who was not included in the new study. “We’ve never had such evidence of that before.”
In a handful of experiments, the researchers did so demonstrated at least some types of sponges are capable of slow crawling by shrinking and spreading during the day and week. “It’s one thing to know that a sponge is capable of this in the lab. It’s another thing to see how it goes in the wild, ”said Stephanie Archer, a marine ecologist from the University of Louisiana Marine Consortium who did not participate in the newspaper.
In order to see the extreme habitat of deep-sea sponges, the team of dr. Morgantija turned to the videos and pictures they took in 2016 Polarstern, a research vessel and an icebreaker.
Images from Polarster show a community of more than 10,000 sponges (diameter in diameter from coin size to hoop size) so dense that it almost covered the upper peaks of Langseth Ridge.
Traces of spicules, skeleton-like structures spilled by sponges, are intertwined between and between the animals. The researchers found that traces of the spicule were visible on 70 percent of the hundreds of images of live sponges examined for the study.
The question remains how and why sea sponges move in the deep polar seas, said Dr. Morganti. They are most likely squirming toward food or away from their biological parents, she said.
Marine biologists are also unsure of the Langseth Ridge trail, as the habitat is largely undisturbed by water currents. Deep-sea sponges can live decades, for centuries or even millennium and previous laboratory tests have accelerated the movement of the sponge at a riveted pace four millimeters a day or a a few millimeters a month (depending on the assessment you are consulting).
“The snail would be much faster,” Ms. Downey said. “It probably happens that thousands of sponges are moving around the world at this moment. We just don’t see it. “When it comes to Langseth Ridge’s network of spiral trails, she said, ‘Those trails could be a stop-start, a stop-start over a decade or even hundreds of years.’
Ongoing research by dr. Morgantia aims to explain exactly how sea sponges manage to survive – let alone migrate – on the cold, dark, nutritious peaks of the barren underwater mountains near the North Pole. “How can these massive sponges survive in such an extreme environment?” she said.
Traces of spicules provide tempting evidence that (despite their anatomical simplicity) sponges may be able to perceive stimuli from the environment and inspire them toward food.
And since sponge species on the Langseth Reef are also found in waters off the coasts of Norway, Russia, Canada, Greenland and Iceland, their newly discovered mobility could also be more widespread.
“This reminded me of why I fell in love with sponges,” said Dr. Archer on new findings. “Every time we think we’ve figured them out, it surprises us.”