In silent depths From the Pacific, far from all solar light, a tiny creature reinvents the rules of survival. Of the sea spiders kind Sericosura cultivate, on their own shells, Methanotrophic bacteria which serve them as food. This amazing partnership, confirmed by a study published in PNASredefines our understanding of symbioses marines.
Methane ooys: a hidden ecosystem where life feeds on chemical energy
Several hundred meters below the surface, the light disappears completely. In this dark world, life no longer depends on the photosynthesis But from the chemosynthesis. Thanks to this process, some microbes transform compounds such as methane or hydrogen sulfide organic matter.
Thus, around methane ooys, real real Submarine oasis. These areas, although geographically limited, are home to unexpected biodiversity. However, spiders Sericosura Almost systematically appear there, always associated with substrates rich in methane. This coincidence strongly suggests that they have developed a specific adaptation to these Extreme environments.
The sites of Sea, Green sticks et Relativelocated off California and Alaska, are among the rare places where these spiders have been observed. Again, their targeted presence shows that they draw a direct advantage of Special chemical conditions of these habitats.
A single nutrition mode: breeding bacteria directly on their bodies
Unlike their predatory cousins, these miniature spiders – barely a centimeter long, have neither pliers to capture a prey, nor suitable oral parts to suck fluids. Therefore, they do not hunt. Instead, they exploit a remarkable strategy: raise bacteria directly on their shell.
Isotopic analyzes reveal a high proportion of Methanic carbon in their fabrics. In addition, in the laboratory, when living specimens are exposed to methane marked at carbone 13their digestive fabrics quickly display a significant incorporation of this carbon. This experience proves that methanotrophic bacteria, installed on their exoskeleton, constitute their main energy source.
Thanks to these microbes, which transform ambient methane into sugars and fatsspiders can feed in brushing their own body. Thus, they harvest a living culture that they maintain permanently. It is therefore a real microscopic agricultureand not a simple passive transport of microbes.
A symbiosis transmitted from birth: a vital heritage for survival
The discovery goes even further. Indeed, some bacteria also colonize Eggs worn by males. These, wrapped around their legs, benefit from microbial protection even before hatching.
Consequently, young spiders are born already equipped with their bacterial gardenready to exploit this resource. This transmission verticale testifies to a joint long -term development between the spider and its bacteria. In an environment where food is rare, this alliance becomes a guarantee of survival.
Finally, this discovery illustrates how the Deep marine life is able to imagine extreme strategies to adapt to hostile conditions. And she recalls that there are still countless mysteries to be unraveling in the abyss.