Watch first video of a doable uncommon sponge reef discovered close to California
Huge mounds of sponges stretching for tons of of metres have been found 600 metres down close to the Channel Islands off California
Huge mounds fabricated from the skeletons of glass sponges have been found 600 metres down on the seabed of the Channel Islands Nationwide Marine Sanctuary off California. The mounds are in contrast to something discovered earlier than within the space and could possibly be examples of a really uncommon form of habitat referred to as a sponge reef.
The reef-like mounds have been first noticed by researchers in 2020, throughout a dive by a remotely operated automobile (ROV) from the analysis ship EV Nautilus.
“We began seeing patches of useless sponges,” mentioned Abigail Powell, a contractor for the US Nationwide Oceanic and Atmospheric Administration, throughout a digital speak at the Ocean Sciences Assembly 2022. “It simply acquired denser and denser, and shortly we have been climbing over nice mounds of it.”
The world is comparatively properly explored, so the invention was a shock. “There have been many dives right here over time, however by no means over this explicit monitor,” mentioned Powell.
The mounds consist primarily of the silica skeletons of useless glass sponges, turned brownish by a coating of sediment. Nevertheless, there are numerous different species dwelling on and within the mounds, together with fish, clams and sponges of each the reef-building and non-reef-building sorts.
In 2021, the ship returned to the sponge mound web site and an ROV zigzagged over two of the mounds. This revealed that the biggest mound was greater than a kilometre lengthy, 500 metres broad and no less than a number of metres thick in some locations.
“The continual extent of the patches over tons of of metres is in contrast to something we've encountered earlier than,” Powell mentioned.
Sponge reefs have been frequent in the course of the time of the dinosaurs, however have been thought to have vanished utterly from fashionable oceans. Then within the Nineteen Eighties, dwelling sponge reefs have been discovered off the coast of British Columbia in Canada, and a couple of others have been discovered elsewhere.
“Glass sponge reefs are spectacular, however fragile, ecosystems,” mentioned Powell.
Nevertheless, she is hesitant about calling the mounds off California sponge reefs till acoustic scans reveal their deeper construction.
“We have to discover out whether or not the mounds are composed of sponge skeletons or whether or not we're taking a look at a comparatively skinny layer of sponge rising on rocky ridges,” Powell advised New Scientist.
“I feel ‘reef-like’ could be a great way to explain what we discovered till we all know extra.”
What is obvious is that the proportion of dwelling reef-building sponges on the floor of the mounds is way decrease than on the reefs off Canada.
It isn’t recognized whether or not it is a pure phenomenon defined by native environmental variations between the 2 websites, or whether or not one thing has killed numerous the reef-building sponges within the Channel Islands Nationwide Marine Sanctuary.
“There are nonetheless many unanswered questions,” mentioned Powell.
Whereas trawling is allowed in elements of the sanctuary, the sponge mounds are in a no-take zone and so needs to be protected against all sorts of fishing.
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