Paul Gilster at Centauri Dreams writes of a scientific paper he’s reviewing that analyzes the potential oxygenation in Europa’s sub-crustal ocean.
We know Europa has liquid water beneath its icy veneer. The challenge for those seeking off-Earth life is considerable. There may well be water, but life as we know it still needs oxygen to breathe. Where would it come from?
We’ve seen evidence for processes by which water is broken down into its constituent elements: the hydrogen and oxygen clouds above the Earth, oxygen in the rings of Saturn, to name two. Radiation might break down the Europan surface ice, and some transport mechanism might deliver the oxygen to the inner ocean.
That ocean is considerably deeper than Earth’s. Notice the inner layers of rock and metal. That part of Europa’s interior is more guesswork, but we know how much that moon weighs, and we can extrapolate from there the percentages of ice, water, stone, and metal.
Gilster quotes from the abstract, “Such an ocean would be energetically hospitable for terrestrial marine macrofauna. The availability of reductants could be the limiting factor for biologically useful chemical energy on Europa.”
Then adds the understatement:
If the term ‘macrofauna’ doesn’t get your attention, nothing will.
It sure got my attention. Examples of macrofauna would include giant squid, sharks, and whales. The latter would be impossible to find swimming the Europan ocean (whales evolved from land animals) but animals the size of these creatures would have no lack of oxygen or energy to live on this moon. And depending on the mineral content, possibly without environmental suits.
Another interesting point: there might be far more extra-terrestrial environments hospitable for dolphins and whales than for humans.
7 January 2008 at 5:40 pm
So long, and thanks for all the fish? ;)
7 January 2008 at 7:10 pm
lol, good point, Jeff.
10 May 2008 at 11:40 pm
does this meen i can drink clean water now?lol
10 May 2008 at 11:41 pm
im sure it’s cleaner there
11 May 2008 at 5:18 am
All kinds of salts might be dissolved in the water there. Remember this is a global ocean under a crust of ice. Probably not fresh water.
11 May 2008 at 11:38 am
I’m pretty sure “macrofauna” refers more to organisms resembling animals than a descriptor of relative size. As in something the size of a trout or a small crab.
I’m quite interested to see the results of a Europan mission, given it’s the most likely place for life in this solar system.
11 December 2008 at 12:14 am
[...] Catholic Sensibility posted some news on Paul Gilster’s post on Europa’s possible macrofauna… all sparked by an abstract that I reproduce here… Europa is a prime target for astrobiology. The presence of a global subsurface liquid water ocean and a composition likely to contain a suite of biogenic elements make it a compelling world in the search for a second origin of life. Critical to these factors, however, may be the availability of energy for biological processes on Europa. We have examined the production and availability of oxidants and carbon-containing reductants on Europa to better understand the habitability of the subsurface ocean. Data from the Galileo Near-Infrared Mapping Spectrometer were used to constrain the surface abundance of CO2 to 0.036% by number relative to water. Laboratory results indicate that radiolytically processed CO2-rich ices yield CO and H2CO3; the reductants H2CO, CH3OH, and CH4 are at most minor species. We analyzed chemical sources and sinks and concluded that the radiolytically processed surface of Europa could serve to maintain an oxidized ocean even if the surface oxidants (O2, H2O2, CO2, SO2, and SO4 2?) are delivered only once every 0.5 Gyr. If delivery periods are comparable to the observed surface age (30–70 Myr), then Europa’s ocean could reach O2 concentrations comparable to those found in terrestrial surface waters, even if 109 moles yr?1 of hydrothermally delivered reductants consume most of the oxidant flux. Such an ocean would be energetically hospitable for terrestrial marine macrofauna. The availability of reductants could be the limiting factor for biologically useful chemical energy on Europa. [...]