Hello and happy Microbe Monday! I hope this edition finds you well.

I don't have work today, or for around a month, so this one is getting posted a bit later than usual. I usually get up at like 5 AM, but had the luxury of sleeping in til 8 today :)

The Taylor Glacier of the McMurdo Dry Valleys in Antarctic bleeds. There is just a waterfall of deep red, bloody water that spouts from the side down onto West Lake Bonney. I assume this was an absolutely horrific sight to the 1911 Terra Nova Expedition guys, particularly Thomas Griffith Taylor, who named it. It is regrettable it did not start doing cosmic horror to him, given that he was a shitty race scientist guy.

You may be wondering several things, most notably, why in God's name is the world bleeding? Why is there so much blood? Why is it there, at the frozen ends of the earth? Can God save us? No, silly, of course He can't. This is the domain of Microbes.

At first the Terra Nova guys believed this was just some red algae, and not, in fact, outflow from the pitted and bleeding corpse of the True God, soon to wake and smite them for their unholy castigation of their fellow man. This is silly, of course. Algae are so-called eukaryotes and as such I barely respect them. They wouldn't do something this cool.

So one thing to note is that the Taylor Glacier (the one that is bleeding (the one that is named after the shitty race scientist guy)) is that it isn't actually fully frozen. Most glaciers are pretty much frozen down to the bedrock, but this one actually has pockets of liquid water far beneath the surface. This is because of the presence of all sorts of salts! They form eutectic mixtures with the water which effectively lowers the freezing point of the liquid and creates these awesome subglacial brine pools.

The pools are really cold and hypersaline (-7 °C, 8% NaCl vs typical seawater which has 3.5% salts in general), of course, and full of all sorts of nasty chemicals and large amounts of iron, they're fully devoid of oxygen, have minimal organic material, and they're almost fully shut off from the rest of the world so naturally, it's sterile- just kidding really weird microbes have been growing there for a very long time. Like 1.5-2 million years or thereabouts.

The community are invariably able to resist all of those aforementioned conditions, so it isn't particularly diverse. Even so, some really incredible metabolism seems to be at work based on chemical analyses of the environment. This is a place with an almost negligible amount of carbon input; photosynthesis does not work there, there's no "easy" way to get more carbon.

There's so much to talk about with these little guys, and so much still unknown since these studies are kinda hard to get funded and also to do, especially without disturbing this environment. I'm going to focus on sulfur, however. These communities appear to cycle sulfur, and they do so in a proportion greater than the amount of sulfur they'd need to construct and maintain their cells. They do not need this much of it and they're spending a lot of very limited energy on it.

Basically the running theory is that they've hotwired their respiration to utilize sulfur instead of oxygen as the oxidizer, and ferrous iron as the terminal acceptor. A bunch of reoxidation reactions can happen thereafter which create free energy. Basically, there's a really, really weird chain reaction that lets them maintain the sulfur and ferrous iron concentrations. Some of it leaches out and forms that rusty brine that appears like blood. Basically, this is a self-contained, active catalytic sulfur cycle that's able to maintain bioenergetic viability over truly vast periods of time. This thing has been bleeding since well before there were humans.

It's really hard to condense the weird biochemistry to something coherent, but it makes my brain vibrate at great and terrible speeds. It's so weird and I love it and I hope at least some part of this was interesting.

Happy microbe monday! I'd like to give a special thanks to our friend Alexandra Elbakyan for assistance in researching the literature on this topic.

Remember that you are more interesting and microbially rich than you realize!