Life on ice

I'm currently reading planetary scientist Sarah Stewart Johnson's wonderful book The Sirens of Mars, about the search for signs of life on Mars (and other planets in the Solar System).  What strikes me whenever I read anything on this topic is that everything we've learned supports the contention that life is common in the universe.  (Not necessarily intelligent life; as I've dealt with before, that's another discussion entirely.)  As I learned from another great book I read a while back, Michael Ray Taylor's Dark Life: Martian Nanobacteria, Rock-Eating Cave Bugs, and Other Extreme Organisms of Inner Earth and Outer Space, every place we've looked on Earth -- however seemingly inhospitable -- we've found living things.  Fissures in rocks miles underneath the Earth's surface; deep-sea hydrothermal vents under crushing pressures and sky-high temperatures; brine ponds containing water many times the salinity of seawater; alkaline and acidic hot springs; chilly, pitch-dark caves with toxic air; anaerobic, sulfur-filled mud.  Teeming with life, all of them.

Not only that, but the building blocks of life are kind of everywhere.  When Stanley Miller and Harold Urey did their mind-blowing experiment back in 1953, it was unclear whether they had just happened on the right formula; they'd included their best guesses as to the constituents of the early Earth's atmosphere, and used artificial lightning as an energy source, and in short order they had organic compounds in enormous quantities.  It turned out, though, that the results had been not so much of a happy accident as an inevitability.  As long as you have (1) a reducing atmosphere (i.e. no free oxygen), (2) inorganic sources of carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur, and (3) some kind of an energy source, you end up synthesizing all twenty amino acids found in living things (plus some we don't use), DNA and RNA nucleotides, simple sugars, fatty acids, glycerol, and a host of other organic compounds.

In other words, every monomer you need to build an organism.  All from off-the-shelf inorganic chemicals and some kind of power source.

What became clear after Miller and Urey published their results is that the early Earth's seas -- and by extension, the seas of any planet with a reducing atmosphere and sufficient liquid water -- might be expected to be brimming with the building blocks of life.  This so-called "primordial soup" on Earth gave rise to primitive life in a relative flash, and there's no reason to expect the same wouldn't happen elsewhere.

What came as something of a shock, though, is that you don't even need warm, Earthlike conditions to generate biochemistry.  Not long ago, astrophysicists started finding the characteristic signatures of organic compounds in interstellar nebulae.  And just last week researchers at the University of Copenhagen announced that they'd discovered organic compounds in a cloud of gas, dust, and ice called Chameleon 1 -- one of the coldest, darkest places ever to be studied, located about six hundred light years away.

The Tarantula Nebula [Image courtesy of NASA, ESA, CSA, STScI, and the Webb ERO Production Team]

Detected by their spectroscopic fingerprints -- the characteristic frequencies of light they absorb from the ambient starlight -- these chemicals were located during a new study using the James Webb Space Telescope.  "With the application of observations, e.g. from ALMA [the Atacama Large Millimeter Array, which was also used in the study], it is possible for us to directly observe the dust grains themselves, and it is also possible to see the same molecules as in the gas observed in the ice," said Lars Kristensen, who co-authored the study.

"Using the combined data set gives us a unique insight into the complex interactions between gas, ice and dust in areas where stars and planets form," added Jes Jørgensen, who also co-authored.  "This way we can map the location of the molecules in the area both before and after they have been frozen out onto the dust grains and we can follow their path from the cold molecular cloud to the emerging planetary systems around young stars."

What this shows is that a great many of the compounds in the primordial soup may have formed before the coalescence of the Earth, and might already have been present when the seas formed.  "This study confirms that interstellar grains of dust are catalysts for the forming of complex molecules in the very diffuse gas in these clouds, something we see in the lab as well," said Sergio Ioppolo, another co-author.

Further evidence that biochemistry -- and almost certainly life -- is plentiful in the universe.

I wonder what life is like on other worlds.  Surely whatever it is, it's evolved into a host of forms completely different from what we have here, ones that have adapted to whatever the local conditions are.  Different sets of environmental challenges would generate new and innovative evolutionary solutions, as would a different set of one-off occurrences (such as the Chicxulub Meteorite collision that ended the supremacy of the dinosaurs and put us mammals on the pathway to pretty much running the place).  Now, take that diversity, those "endless forms most beautiful and most wonderful," as Darwin so trenchantly put it -- and multiply that by a million times.

That is what is very likely to be out there in the cosmos.

If I can be forgiven for ending a post with a quote by Carl Sagan two days in a row, the line he put in the mouth of his iconic character Ellie Arroway (from the book and the movie Contact) seems apposite: "If we're the only ones in the universe, it seems like an awful waste of space."

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Trapped in the ice

Today in the "I've Seen This Movie, And It Didn't End Well" department, we have: scientists digging into glacial ice and finding heretofore-undiscovered species of viruses and bacteria.

Just this week, a paper called "Glacier Ice Archives Fifteen-Thousand-Year-Old Viruses" was released as a preprint on bioRxiv, detailing work by a team led by Zhi-Ping Zhong of Ohio State University.  Here's what the scientists themselves write about the research:

While glacier ice cores provide climate information over tens to hundreds of thousands of years, study of microbes is challenged by ultra-low-biomass conditions, and virtually nothing is known about co-occurring viruses.  Here we establish ultra-clean microbial and viral sampling procedures and apply them to two ice cores from the Guliya ice cap (northwestern Tibetan Plateau, China) to study these archived communities...  The microbes differed significantly across the two ice cores, presumably representing the very different climate conditions at the time of deposition that is similar to findings in other cores.  Separately, viral particle enrichment and ultra-low-input quantitative viral metagenomic sequencing from ∼520 and ∼15,000 years old ice revealed 33 viral populations (i.e., species-level designations) that represented four known genera and likely 28 novel viral genera (assessed by gene-sharing networks).  In silico host predictions linked 18 of the 33 viral populations to co-occurring abundant bacteria, including Methylobacterium, Sphingomonas, and Janthinobacterium, indicating that viruses infected several abundant microbial groups.  Depth-specific viral communities were observed, presumably reflecting differences in the environmental conditions among the ice samples at the time of deposition. 

On the face of it, it's unsurprising they're finding new viruses, because we find new viruses wherever we look in modern ecosystems.  Viruses are so small that unless you're specifically looking for them, you don't see them.

But four new genera of viruses is a little eyebrow-raising, because that means we're talking about viruses that aren't closely related to anything we've ever seen before.

This, of course, brings up the inevitable question, which was the first thing I thought of; what if one of these new viruses turns out to be pathogenic to humans?  The majority of viruses don't cause disease in humans, but it only takes one.  Science fiction is rife with people messing around with melting ice and releasing horrors -- this was the basic idea of The Thing, not to mention The X Files episode "Ice" and best of all (in my opinion) the horrifying, thrilling, and heartbreaking Doctor Who episode "The Waters of Mars," which is in my top five favorites in the entire history of the series.

So I'm hoping like hell the research team is being cautious.  Not that it ever made any difference in science fiction.  Somebody always fucks up, and large amounts of people end up getting sick, eaten, or converted to some horrifying new form that goes around killing everyone.

Lest you think I'm just being an alarmist because I've watched too many horror movies, allow me to point out that this sort of thing has already happened.  In 2016, permafrost melt in Siberia released frozen anthrax spores that sickened almost a hundred people, one fatally, and killed over two thousand reindeer -- after that region not seeing a single case of anthrax for at least seventy years.

On the other hand, it's understandable that the scientists are acting quickly, because the way things are going in the climate, glaciers will be a thing of the past in fairly short order.  Glaciers and polar ice sheets are time capsules, layer by layer preserving information about the climatic conditions when the ice was deposited, even trapping air bubbles that act as proxy records giving us information about the atmospheric composition at the time.  (This is one of the ways we've obtained carbon dioxide concentrations going back tens of thousands of years.)

However, it also preserves living things, including some that seem to retain their ability to be resuscitated nearly indefinitely.  I try not to panic over every little risk, but I have to admit this one has me spooked.  We don't have a stellar track record for caution, but our track record for saying, "Oh, yeah, this'll work!" and then unleashing a catastrophe is a good bit more consistent.

So let's be careful, okay, scientists?  I'm all for learning whatever we can learn, but I'd rather not be turned into a creepy evil being with a scaly face dripping toxic contagious water all over the place.  Call me picky, but there it is.

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This week's Skeptophilia book of the week is scarily appropriate reading material in today's political climate: Robert Bartholomew and Peter Hassall's wonderful A Colorful History of Popular Delusions.  In this brilliant and engaging book, the authors take a look at the phenomenon of crowd behavior, and how it has led to some of the most irrational behaviors humans are prone to -- fads, mobs, cults, crazes, manias, urban legends, and riots.

Sometimes amusing, sometimes shocking, this book looks at how our evolutionary background as a tribal animal has made us prone all too often to getting caught up in groupthink, where we leave behind logic and reason for the scary territory of making decisions based purely on emotion.  It's unsettling reading, but if you want to understand why humans all too often behave in ways that make the rational ones amongst us want to do repeated headdesks, this book should be on your list.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]