Energy for microbial life on Europa

The planet Jupiter's moon Europa may harbour a subsurface water ocean, but estimates of the available free energy have not been encouraging for supporting life. Here I show that disequilibrium chemistry in the ocean's ice cover, driven by charged particles accelerated in Jupiter's magnetosphere, should produce enough organic and oxidant molecules to fuel a substantial Europan biosphere. Microbial life could exist in concentrations detectable by surface landers able to filter meltwater from Europa's ice.