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New carnivorous harp sponge discovered in deep sea

The views expressed are those of the author and are not necessarily those of Scientific American.


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Chondrocladia lyra

Chondrocladia lyra, a new species of carnivorous harp sponge. Credit: MBARI

You may remember the Monterey Bay Aquarium Research Institute (MBARI) from such discoveries as the Yeti crab, the squid with elbows and my personal favourite, the pigbutt worm, and now they’re back with footage of a new species of carnivorous sponge.

Seventeen years ago, Jean Vacelet and Nicole Boury-Esnault from the Centre of Oceanology at France’s Aix-Marseille University provided the first real evidence that a sponge could be more than, well, a sponge. They had discovered a new species of deep-sea sponge living in the unusual setting of a shallow Mediterranean sea cave, the inside of which mimicked the conditions of its usual habitat more than a kilometre below the surface. This allowed the researchers an unprecedented view of the sponge’s eating habits, and they watched as it snared its prey of small fish and crustaceans instead of absorbing bacteria and organic particles through their bodies, like most other sponge species do – including ones living in the very same cave.

Vacelet and Boury-Esnault’s sponges were of the Asbestopluma genus and belonged to the Cladorhizidae family of carnivorous demosponges – the class that contains over 90% of the world’s sponges. Since reporting their discovery in a 1995 issue of Nature, 24 new species of cladorhizid sponges, including the incredible ping-pong tree sponge (see below), have also been discovered. Yet due to the difficulty of studying their behaviour at such incredible depths, researchers have had little opportunity to describe essential aspects of their lives, particularly how they reproduce.

Chondrocladia sponge

Chondrocladia, or ping-pong, sponge. Credit: MBARI

Which is where MBARI’s remotely operated vehicles (ROVs) Tiburon and Doc Ricketts, come in. Using these deep-diving vessels, a team of researchers led by Senior Research Technician Lonny Lundsten discovered a species of harp sponge called Chondrocladia lyra off the coast of California, at depths of 3316–3399m.

As Mr_Skeleton pointed out on Reddit this week, this sponge doesn’t look like it could clean anything. But it can catch prey, envelop it in membrane and digest it whole, so it certainly has other priorities. Based on footage of several individuals and two large, fragmentary specimens brought up by the ROVs, Lundsten’s team described how the vertical branches and horizontal stolons that make up the sponge’s basic harp-like structure, called a vane, are covered in barbed hooks and spines. They found that a number of crustacean prey were passively ensnared on these branches thanks to the Velcro-like hooks and then aggressively enclosed in a cavity to be dismembered into small, digestible particles, which provided direct evidence of the species’ carnivorous appetites.

C. lyra can grow up to 37cm long – impressive for a sponge – and are anchored to the sea-floor by a structure called a rhizoid, which looks like a root system. They can have 1-6 vanes, each supporting a number of equidistant vertical branches, and each of these end in swollen terminal balls. According to the researchers, these terminal balls produce condensed packets of sperm called spermatophores, which are released into the surrounding water in the hopes of fertilising other harp sponges in the area. Each C lyra sponge also has an egg development area around the mid-point of the branches, and when the spermatophores make contact, these areas swell up as the eggs are fertilised and begin to mature.

chondrocladia

The vertical branches of the harp sponge are tipped by swollen terminal balls containing packets of sperm. Credit: MBARI

The team suggests that the structure of the harp sponge is designed to ensure that they catch the most prey possible, and also maximise their chances of catching spermatophores from other harp sponges.

“Video footage taken as the ROVs approached specimens of C. lyra provided information about the biological diversity of the areas in which the sponges live,” the researchers added in their report in the current issue of Invertebrate Biology. “Among the coexisting invertebrates were unidentified sea anemones; the soft coral Anthomastus robustus, members of several species of sea pens; and the sea cucumber Paelopadites confundens, as well as another sea cucumber in the family Elipidiidae.”

Here’s some video footage of the new harp sponge:

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Bec Crew About the Author: Bec Crew is a Sydney-based science writer and award-winning blogger. She is the author of 'Zombie Tits, Astronaut Fish and Other Weird Animals' (NewSouth Press). Follow on Twitter @BecCrew.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. rvcanuck 9:27 pm 11/8/2012

    A carnivorous sponge? The one-percenter jokes write themselves…

    Link to this
  2. 2. stargene 4:06 am 11/9/2012

    OK.. if you’d told me that the Ping Pong Sponge
    was actually an alien from a recently discovered
    super-earth ocean 50 light years away, spotted
    by the VLTI (Very Large Telescope Indeed) I’d
    have been tempted to believe you!

    Link to this
  3. 3. Bird/tree/dinosaur/etc. geek 8:58 am 11/9/2012

    Carnivorous sponges? What next? Evil sentient corals? Militant sea otters? ;)

    Seriously, good article. Excellent job staying serious.

    Link to this
  4. 4. Charles Hollahan 10:15 am 11/9/2012

    Very interesting discovery, I would like to know more about the distribution of these sponges. How many per given area.

    The marine snow in the videos is very dense, much greater than I expected so are these areas near the terminus of submarine canyons?

    I expect that the genomes of the sponges to be very old. Just have to watch and see.

    Link to this
  5. 5. Charles Hollahan 5:35 pm 11/9/2012

    Considering that sponges eat bacteria as well as other types of plankton they have always (I can’t think of any which fix carbon themselves) been heterotrophs so maybe it would be better to mention this and so labeling them carnivorous isn’t so new and unusual for sponges.

    Fleas and mosquitoes are called micropredators so sponges could be in the range of mirco to nano. Nanopredators. Nanopredatory sponges. I could get used to that.

    The Harp Sponges would be categorized by the largest prey items they could handle under this scheme, centi- or deci-predators.

    Link to this
  6. 6. Becky Crew in reply to Becky Crew 7:25 pm 11/9/2012

    Hi Charles,

    Good point, I like nanopredatory sponges too! The researchers chose to call it carnivorous throughout their paper, so I followed suit. Unfortunately they don’t mention anything about the species’ distribution, I guess they don’t really know at this stage!

    Bec

    Link to this
  7. 7. Charles Hollahan 8:37 pm 11/9/2012

    Thanks Becky, I thought that would be the case. There were a number of different individuals in the film so I thought it might be possible that some survey might have been made.

    This really is a great change from the method most sponges have so I can understand the reason they point that out. External capture instead of internal capture.

    Looks like I’ll have to wait until there’s more work on this species. Thanks for the blog! Makes finding new things more fun since I don’t get access to lots of journals and try to stick to a topic when I do look. Charles

    Link to this

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