- Possible ecosystems and the search for life on Europa
Could There Be Europan Macrofauna?
It is natural to wonder whether analogs to giant squid or other macrofauna might exist in the europan ocean. Terrestrial metazoa require high levels of dissolved oxygen. For example, benthic macrofauna require O2 concentrations above 20 µM (70). Even in a complete absence of O2 sinks in Europa's ocean, the production rate of O2 from H2O2 derived above would require 200 million years to oxygenate Europa's entire ocean to this level. Calculating H2O2 via n = FGt would decrease this time to 5 × 104 yr, but this requires significant recycling of the upper meter of Europa's ice. If this does not occur, and if we assume that europan macrofauna would face the same high-energy respiration requirements as terrestrial macrofauna, we are challenged to find a sufficient source of O2 production in the absence of photosynthesis.