MICROBE 2018 recap - Astrobiology: The History of the World, A Microbial Perspective

So I made it on time to this session...

Before I launch into the glory of astro-micro-biology - I was amused by the starting comments of the session. ASM hands out guidelines for sessions that include the suggestion that you should present learning objectives for the session...so we know what we are getting ourselves into. This was the only session where I saw this presented. It was actually kind of neat; high school student, college student, graduate student, seasoned full professor-die-hard-academic... we all benefit from organizing our thoughts and goals. So kudos to the Astrobiology session for doing this! And kudos to ASM for their app on this meeting - it made tracking and zooming to sessions as well as 'rating' sessions and talks very easy.

Jennifer B. Glass is an Assistant Professor at Georgia Tech with a primary research interest in Biogeochemistry. If we shamelessly stalk her on google we find her interests include: (i) anaerobic oxidation of methane, (ii) greenhouse gas cycling - focus methane/nitrous oxide, (iii) biogeochemical cycling (iv) marine microbiology as it pertains to anaerobic metabolisms (v) integrating omic and geochemical datasets and (vi) coevolution of microbial metabolisms and ocean chemistry over Earth's history - whew!

She's been a NASA Astrobiology Postdoc, PEO Scholar and NSF Graduate Research Fellow and if you'd like to take a look at her lab and research check out her website and google scholar profile!

My favorite part of her lab page -

Failure required, tears optional, please don't lick the science! 

So this morning we are talking astrobiology and specifically Jennifer gives us a primer of what's to come and warns us there is jargon but they've made efforts to keep it to a minimum.

The highlights!

https://en.wikipedia.org/wiki/Boring_Billion

• During the Haldean (beginning of the Earth), the Earth was being resurfaced via bombardment by meteroites, it was hot too hot for life presumably and there are debates about whether there was liquid water.
• The earliest life is thought to be around 3.7 billion years ago - no ozone, no oxygen and lots of radiation!

Detour - If you want to know about bugs that love radiation, check out Deinococcus it's a pretty sexy radiaton-loving microbe.

Ott, Emanuel, et al. "Proteometabolomic response of Deinococcus radiodurans exposed to UVC and vacuum conditions: Initial studies prior to the Tanpopo space mission." PloS one 12.12 (2017): e0189381.

Frösler, Jan, et al. "Survival of Deinococcus geothermalis in Biofilms under Desiccation and Simulated Space and Martian Conditions." Astrobiology 17.5 (2017): 431-447. (paywalled - which blows, but if you can get it via your school.)

Wolf, Jordan. "Applications of Extremophiles in Martian Astrobiology." (2016).

• At the boundary of of the Archean and Proterozoic you have the Great Oxidation Event (GOE) and an ozone layer forms.
• In our Earth's history we have the Haldean Earth, GOE, the Rodinia Supercontinent, Snow ball Earth and Ice Ages...these were all discussed as Alternative Earths.
• Astrobiologists look for 'biosignatures' which, as defined, is a pattern whose origin requires a biological agent.
• Earliest isotopic evidence of microbial life is approx 3.95 Ga (stable isotopes are important!)
• Microbes flourish after mass extinction events.
• Solar luminosity has increased through time. During the Haldean we were only getting about 75% of our sun. During this 'faint' sun methanogens abounded. Our atmosphere was CO2 and CH4 causing a 'haze'.
• For habitability what do you need? Liquid water, essential elements and atmospheric gases specifically 'biosignature' gases (oxygen, methane, sulfur)
• Take a look at this latest (as of the conference) issue of Science mag articles:

Background levels of methane in Mars’ atmosphere show strong seasonal variations

Organic matter preserved in 3-billion-year-old mudstones at Gale crater, Mars

• Studies that are proposed, scheduled, in talks...
• Enceladus and Titan studies pending/ongoing. It'd be interesting to note what are the pressure limitations of methanogens. Looks promising:

• Biological methane production under putative Enceladus-like conditions

• Proposed Europa lander mission in 2024
• Exoplanets are worth considering as well... 51 Pegasus B was discovered in 1995. Exoplanets open a new realm of consideration!
• Schwieterman et al., 2017. Exoplanet Biosignatures: A Review of Remotely Detectable Signs of Life

Excited about Astrobiology now? You should be! For a primer to get you started check out the aptly named: Astrobiology Primer v2.0

You may also be interested in Stolz's 2017 article: "Gaia and her microbiome". 

I took several pics of Jennifer's talk but then realized ASM was asking us not to take pictures of sessions - so alas...they are just for me! But if you contact Jennifer's lab or take a look at any of her publications you'll most likely see a lot of what she presented... to get you started, she cited work from Freude and Blaser, Tashiro, and Mata and Bottjer.