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rfmcdonaldTowleroad linked to a fascinating NASA discovery.
As I noted earlier, it's quite possible to sustain complex biospheres without sunlight, seafloor organisms "break[ing] the chemical bonds of the up-gushing hydrogen sulfide and use the bond energy to combine oxygen (or nitrate) with carbon dioxide (which comes from seawater) into stable, biologically useable compounds, such as glucose." This has obvious applications for life on Europa, and on other icy moons suspected to have subsurface oceans. Most excitingly, there may be sufficient oxygen in Europa's ocean to fuel these complex biospheres; Europan life might not be limited to micro-organisms.
All this from a NASA probe below the Antarctic. An age of miracles and wonders.
In a surprising discovery about where higher life can thrive, scientists for the first time found a shrimp-like creature and a jellyfish frolicking beneath a massive Antarctic ice sheet.
Six hundred feet below the ice where no light shines, scientists had figured nothing much more than a few microbes could exist.
That's why a NASA team was surprised when they lowered a video camera to get the first long look at the underbelly of an ice sheet in Antarctica. A curious shrimp-like creature came swimming by and then parked itself on the camera's cable. Scientists also pulled up a tentacle they believe came from a foot-long jellyfish.
"We were operating on the presumption that nothing's there," said NASA ice scientist Robert Bindschadler, who will be presenting the initial findings and a video at an American Geophysical Union meeting Wednesday. "It was a shrimp you'd enjoy having on your plate."
[. . .]
The video is likely to inspire experts to rethink what they know about life in harsh environments. And it has scientists musing that if shrimp-like creatures can frolic below 600 feet of Antarctic ice in subfreezing dark water, what about other hostile places? What about Europa, a frozen moon of Jupiter?
"They are looking at the equivalent of a drop of water in a swimming pool that you would expect nothing to be living in and they found not one animal but two," said biologist Stacy Kim of the Moss Landing Marine Laboratories in California, who joined the NASA team later. "We have no idea what's going on down there."
As I noted earlier, it's quite possible to sustain complex biospheres without sunlight, seafloor organisms "break[ing] the chemical bonds of the up-gushing hydrogen sulfide and use the bond energy to combine oxygen (or nitrate) with carbon dioxide (which comes from seawater) into stable, biologically useable compounds, such as glucose." This has obvious applications for life on Europa, and on other icy moons suspected to have subsurface oceans. Most excitingly, there may be sufficient oxygen in Europa's ocean to fuel these complex biospheres; Europan life might not be limited to micro-organisms.
The larger question is whether the ocean floor on Europa actually provides the conditions for life. Here the answer also ties in to that active resurfacing, one that leaves few impact craters intact and suggests that what we see from a spacecraft could be no older than 50 million years or so. Greenberg notes at the ongoing Division of Planetary Sciences meeting in Puerto Rico this week that cracks on the surface continually fill with fresh ice, while surface areas already in place are gradually replaced.
Add in mechanisms for gradually adding fresh material to the surface and you’ve exhausted the possibilities for resurfacing. But they’re all Greenberg needs to estimate that the delivery rate of oxidizers into the ocean is fast, so fast that the oxygen concentration of this sub-surface ocean could exceed that of Earth’s oceans in just a few million years. The upshot: This is enough oxygen to support not just micro-organisms but larger creatures, macrofauna whose metabolisms demand more oxygen.
And this is intriguing: Greenberg argues that it would have taken a couple of billion years for the first oxygen to reach the ocean. That delay could be crucial, for early organic structures could be disrupted by oxidation. On Earth, oxygen’s late arrival allowed life to go from pre-biotic chemistry to organisms that evolved to manage oxygen’s damaging effects. The same mechanism might have allowed creatures to emerge in Europa’s ocean.
We’re talking, remember, about a global body of water, one containing about twice the liquid water of all Earth’s oceans combined. If Greenberg is right, that ocean contains a hundred times more oxygen than previously estimated, allowing roughly 3 billion kilograms of macrofauna to subsist if their need for oxygen is roughly the same as we find in terrestrial fish.
All this from a NASA probe below the Antarctic. An age of miracles and wonders.
