Beneath the icy crust of Europa, Jupiter's fourth-largest moon, is an ocean of liquid water more voluminous than all of Earth's oceans combined. On Earth, wherever there's water, there are bacteria; wherever there are bacteria, there are viruses as well. Recently, scientists have found that viruses play an important role by cycling nutrients in Earth's oceans. What might they do on Europa?
I teamed up with Adriana Gómez-Buckley and G. Max Showalter to build a novel model of virus–bacteria interactions in a hypothetical biosphere in Europa's oceans. Our model predicts that viruses may make up a large fraction of the biomass on Europa and, through lysing bacteria to create dissolved organic matter, could support a thin, sub-ice biofilm.
From the perspective of an individual's lifetime, viruses may seem to be a calamity at worst, a nuisance at best. But from the perspective of an ecosystem, viruses may be an indispensable part of achieving longterm homeostasis and driving evolutionary innovation.
Image credit (artist depiction): NASA
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