This video follows a couple divers and their support team, as they cut through nine meters of ice (just under 30 feet, for my USian readers) to dive in the appropriately-named Lake Untersee, a large, freshwater lake on the edge of East Antarctica. It’s frozen over year-round, but there’s still plenty of liquid water, and as Jeff Goldbloom would say, life finds a way.
The picture shows fossilized stromatolites, cut into squares to show the many layers that made up the structure. The upper surface is covered with conical shapes, and you can see how the layers underneath built up to form them.
Normally when I cover research on or around Antarctica, it has to do with this planet’s climate, but Untersee is such a harsh and isolated location that the main interest, aside from studying what’s down there, is in how it might help us find life in extreme conditions on other planets.
What’s down there, it seems, is stromatolites. These are layered structures formed by microbes gluing sand and other stuff together into their microbial mat. Over many generations, they form the alien shapes you can see on the lake floor in the video below. These structures fossilize well, which is probably why stromatolites represent the oldest evidence of life we have on this planet.
The divers’ first attempt, after a few days of digging a hole in ice, was aborted after the rebreather apparatus malfunctioned and started putting chemical-tainted water into the tube one of the divers was supposed to be breathing from. Just after they got the divers out, there was a storm with 100mph/160kph winds that lasted 24 hours, after which they had to dig all the snow out of their diving hole.
I’ve never had a whole lot of interest in learning to use scuba gear. On the one hand, I think it’d be pretty cool to be able to poke around underwater for a while like that, but on the other hand, there are a lot of ways it can go wrong, not to mention that I definitely don’t have the money for a hobby like that. Even if I do take up diving someday, I can guarantee I’ll never try it in a place like Antarctica. I definitely see the appeal, but as with cave exploration, I’m afraid I may just be too much of a coward. As for diving in caves? Yeah, I’ll pass on that. Honestly, I think I’d lump Antarctic lake diving in with cave diving – it may be that there’s less of a maze, but if you’re in an enclosed bubble of water that you had to drill through 30 feet of ice to get through, that counts as a cave, to me.
That said, I’m very glad that there are people who want to take on challenges like that, because I love being able to see this footage.
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Very cool! Stromatolites grow, rather than form. They are colonial and photosynthetic, but generally only form in bodies of water that lack snails or other grazing life that eats them.
Yeah, that distinction makes sense.
I think my reflex was to say “form” because the main structure isn’t alive – just the surface layer – but you could say the same of coral or, from a certain perspective, trees.
More fool me 😛
late to this, but have both seen stromatolites in person, and taken a scuba diving course.
Went on a winter break geology field trip to a small island in the Bahamas back in the 90s, San Salvador, maybe? but there were some inland hypersaline lakes, with stromatolites in them. They were pretty rocky/hard, and would scrape the hell out of your shins if you bumped into them whille wading, so I took to “swimming” when the water was more than a foot deep or so. Didn’t look like much, and would be absolutely unimpressive to almost anyone out of context, but getting your shins barked by the same type of biological colony to leave the oldest fossils is still kinda cool…
Took a group scuba class while enlisted and stationed in Okinawa. probably cheaper because of the group thing, but at the time I was also doing dumb shit like drinking MadDog 20/20 for “financial reasons”, so… I can’t remember the specifics (this was like, two decades ago…), but I think it was a few weekends or so, with equipment rental and dives and such included in the course cost. Nothing particularly difficult, basically “don’t hold your breath”, and especially not while ascending. Some hand signals I don’t remember, and how to use the equipment. If you end up in a tropical/subtropical area for a while, look around and see what’s offered. If nothing else, it’s a lot easier to get close looks at coral and weird inverts compared to snorkeling or freediving.
Also, that was just the basic scuba cert. There are all sorts of additional certifications, for more depth, different conditions, etc. I imagine arctic diving certification probably rivals a typical four-year degree for all the training involved, likely more if they are requiring a certain amount of logged dive hours or whatever. But it doesn’t take much for the pretty typical looky-see at coral and such.
The instructing person/company had some offer for a free advanced course for the person who scored highest on the written tests, which I scored, but couldn’t take advantage of (because: enlisted…), and part of me kinda regrets it, but at the same time, I’ve never used scuba since, and at this point, despite it being a supposedly life-time certification/qualification, I wouldn’t attempt scuba without taking the course again.
There is a large body of literature on stromatolites, thrombolites, and numerous other types of lithic algal organisms. They make calcium carbonate via photosynthesis, so they are quite rocky.
Here in MN, they are found in association with iron, and banded iron formations. If you google Mary Ellen Jasper, you will find examples of very early stromatolites which people have cut and polished as a semi-precious gemstone. The geologists study them as they have ‘exquisite’ preservation of the microbial internal structures.
I’m curious as to what, if any, sedimentation is happening in that environment?
Interesting!
In terms of sediment, Wikipedia says the lake’s main source of water is melt from a connected glacier, so I imagine that’d be the main source of “sediment” as well. The only “outlet” is the very slow upward “flow” of the ice on top as it ablates into the atmosphere, and new ice is added at the bottom.
The deeper portions apparently have a high concentration of hydrogen sulfide, and there’s an anoxic portion at one end with extremely high concentrations of methane in the soil. There’s also a species of “chemolithotroph” that metabolizes hydrogen.
It’s easy to see why folks looking for extraterrestrial life are excited by it.