Sponges leave traces on the ocean floor – sciencedaily

Sponges: These are considered to be one of the most primitive forms of animal life, as they have no organs of locomotion or a nervous system. A team around deep sea scientist Antje Boetius has now discovered that sponges leave traces on the seabed in deep Arctic waters. They conclude that animals can move actively – even if only a few inches per year. They are now publishing these unique findings in the journal Current biology.

The surprise was great when the researchers examined high-resolution images of the seabed of the deep Arctic sea in detail: path-shaped traces through the sediment ended where the sponges were. These trails were observed in all directions, including uphill. “We conclude that sponges could move actively on the seabed and leave these traces as a result of their movement,” reports Dr Teresa Morganti, sponge specialist at the Max Planck Institute for Marine Microbiology in Bremen. This is especially exciting because science had previously assumed that most sponges are attached to the seabed or are passively moved by ocean currents and generally on slopes.

“There are no strong currents in the deep Arctic waters that could explain the structures found on the seabed,” explains the leader of the expedition, Professor Antje Boetius, who works with the great biologist. fund, Dr. Autun Purser of the Alfred Wegener Institute, Helmholtz Center. for Polar and Marine Research (AWI) in the HGF-MPG Joint Research Group for Deep Sea Ecology and Technology. The recently released recordings were made during an 87 ° North expedition to the Karasik Seamount about 350 kilometers from the North Pole with the research icebreaker Polarstern in 2016 with an OFOBS (Ocean Floor Observation) towed camera system. and Bathymetry System). “With OFOBS, we can create 3D models from the deep sea. The top of the seamount was densely populated with sponges. 69% of our images showed trails of sponge spicules, many of which led to living animals, ”Autun Purser reports.

Many questions arise from these observations: why do sponges move? How do they orient themselves? Possible reasons for locomotion could be foraging, avoiding adverse environmental conditions, or distributing offspring. Foraging in particular plays a major role in nutrient-poor ecosystems such as the deep Arctic. The sponges have an important function there anyway. As filter feeders, they can use particles and dissolved organic matter and are intensively involved in the recycling of nutrients and matter through their bacterial symbionts. Sponges also provide useful structures for arctic fish and shrimp to use as habitat. However, scientists have yet to study the mechanisms of locomotion.

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Material provided by Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research. Note: Content can be changed for style and length.

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