At ScienceDaily (June 28, 2011), we learn: “Ancient Symbiosis Between Animals and Bacteria Discovered”
Marine shallow water sandy bottoms on the surface appear desert-like and empty, but in the interstitial space between the sand grains a diverse fauna flourishes. In addition to bacteria and protozoa numerous animal phyla have been found here, some only here. One of the strangest members of this interstitial fauna is Paracatenula, a several millimeters long, mouth and gut-less flatworm, which is found from tropical oceans to the Mediterranean. These worms are the focus of a research project led by Jörg Ott at the Department of Marine Biology of the University of Vienna with funding from the Austrian Science Foundation (FWF).
Strange because
In the early 1970s, at the time of the discovery of Paracatenula, it was already a mystery how the worms acquire their food without a mouth and gut. The solution to this question came unexpectedly: At deep ocean hot vents, giant mouth-less tubeworms were found. These — like Paracatenula — live in symbiosis with intracellular bacteria that oxidize reduced sulfur compounds. The energy obtained in this chemical process is used by the symbionts to fix inorganic carbon into biomass — just like plants do using sunlight. Due to the high productivity of the symbionts, their hosts can derive all their nutrition from them
And
Based on genetic sequences of the symbionts the scientists have roughly extrapolated the age of the symbiosis — the estimated age of 500 million years makes this symbiosis the oldest known animal bacteria association.
Now the researchers want to figure out how they manage to pass it on.
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