The “arsenic life form” created a little bit of media buzz a few days ago. There is even a comic. I was pleasantly unsurprised by the announcement because I (and many others) had been tipped off to its existence earlier, by one of the paper’s co-authors. I love academia.
However, now the entire thing is being questioned as shoddy science. From the perspective of my previous life in molecular biology, the critics do seem to have some good points. The study is preliminary, not conclusive; it looks like the little bacteria could have been squeaking by with just enough phosphorus to replicate without actually incorporating any arsenic into their DNA. But I’m not going to take either side, and instead stick to the big picture. What is the significance of this discovery for astrobiology and environmental ethics?
For astrobiology it is still quite significant. If the microbes incorporated arsenic into their DNA, that is a huge breakthrough, and it is significant for the search for life anywhere, on or off of Earth. If the microbes are just very tolerant of arsenic that is still quite amazing and it is worth investigating them to figure out how they do it. And that still has implications for the search for life beyond our world.
And what about environmental ethics? How’s that connection work? Two things. First, there is truly a whole lot we do not know about even our own planet and what lives on it. We have a lot to learn, and yet we are hell-bent on wrecking it before we even know it exists. Mono Lake was almost destroyed by water diversions in the middle of the last century. Had that succeeded we could have lost this amazing discovery without even knowing of its existence. And no doubt we are doing this all over the world right now. We will never know what we have lost; we are destroying the unimaginable. Maybe we should be more careful.
Second, life also looks like it is a lot tougher than we can imagine. We often talk about “destroying the planet,” but really we are only talking about the parts we are most familiar with: multicellular life, and mostly vertebrates and large plants at that. What if we really did wreck the Earth and drive ourselves extinct? Most likely the extremophiles would just life on, like nothing happened. Obviously, that would be less than ideal. I prefer my planets to habitable for multicellular life.
As a last thought, some people think this discovery somehow proves God does not exist. I’m not sure how that logic works (especially since the person quoted does not seem to know what the paper actually says (pdf is behind a paywall)), but I have to say it’s wrong. This discovery has no bearing on the existence or non-existence of God. When humans discover another species of anything, no one ever says “look, therefore God does not exist!” That would be silly. This is a very interesting find, but nothing to toss out God over.