Thursday, March 11, 2010

The geochemistry of the "Blood Falls"

By the way, a little note from the last column: a reader that is studying economics brought to my attention that matrix modelling is used in the discipline of economics. Nice!

I have to admit, it's a striking image: a glacier that bleeds. It's like something out of an Elric novel, or Ozzy Ozbourne's subconscious. Not only does it make for surreal and sensationalist photographs, but it might tell us a little something about the history of life on earth and possibly where we're headed.

The chemistry behind the "Blood Falls" is astonishing, since it has been a fjord lake trapped inside a small glacier. The water of the antarctic fjord was sealed off by glacier ice over 5 million years ago, before humans stood erect. This caused the water to acquire unique chemical properties that are downright non-earthly.

We take it for granted that water flows around and has contact with the air. When it doesn't, water undergoes a chemical change as a result of the bacteria living inside of it, which chew up the dissolved oxygen. As the environment is closed off, eventually the bacteria burn through the oxygen. Now, oxygen is important in organic chemistry because of its property as an electron acceptor. Deprived of oxygen to bond with, bacteria switch to the second best electron acceptor, which in water is typically nitrogen. Nitrogen is burned through relatively fast, and then they switch to sulfates, creating sulfides...which explains the bad "rotten" smell of stagnant water (and you've gotta love any chemical whose most distinctive characteristic is smelling bad). Sulfur is actually in the same column of the periodic table with oxygen and has similar electron-accepting properties, after all.

(By the way, a note for fans of organic chemistry: you might have heard the term thioether refer to sulfides and so there's a great instinct to think both are the same thing. Sulfides and thioethers are similar but not the same thing. Sulfide is a term to describe pretty much anything that's sulfur with two atoms of carbon including those created by nonliving processes, whereas thioether specifically refers to sulfides created by organic processes.)

Now, sulfates are very reactive with iron. In fact, they're responsible for the process of corrosion. So if you throw some sulfides together with iron, and it catalyzes it, speeding it up until it becomes bright red rust. This gives the red falls it's color. But in the trapped bacteria of the red falls, the iron and the sulfates are actually used as a part of the reaction cycle. This is something that has never been seen before in any living thing on earth.
Let me explain that: these are single-celled organisms that produce their own food...with iron, and without sunlight or much oxygen.

How is this important to understanding the history of life?

Well, there was a period of time around 850-650 million years ago, called the Cryogenian, when the entire planet earth was frozen. There were glaciers in the tropics and the earth's ocean was all ice. If you stop and think about it, that would make the earth a really dead world. There's a lot of back and forth between scientists as to whether the entire earth really could have been frozen...because how could life survive something that shocking for millions of years? Something like this, where a totally different biochemistry for food-producing bacteria is discovered, can change the entire history of life.

Likewise, something like this can also tell us about periods of time that earth's oceans have been deprived of oxygen, called anoxic events. When ocean currents don't circulate, oxygen isn't sent into the water. If oxygen isn't sent into the water, sulfur's used instead, and this produces poisonous hydrogen sulfide. Water itself becomes very lethal to living things - creating "dead zones," and would have turned a deep green hue from the bacterial blooms, not to mention smelling like rotten eggs. These accompany a heating of the earth's atmosphere from events like super-global warming. This in fact might have been part of the cause of the largest mass-extinction in earth's history, between the Permian and Triassic.

This is one of the most exciting areas in the history of life, because it's cutting edge. The role of anoxic events in the hot global temperature that we associate with the age of the Dinosaurs isn't new, but in fact, the idea that anoxic events may have been the agents of mass extinctions are only as old as this decade.

All of this may sound scary and familiar, because it is happening right now. Oceanic deoxygenifaction - or oceanic suffocation, to use the scarier and sexier term - is one of the more anxiety-inducing effects of global warming, huge areas of deoxygenofied water where there's no life.

I usually have some kind of pro-intellectual moral attached to these discussions on cutting edge science, and here's the one for today: there is no such thing as useless scientific research. I am outraged by politicians that decry genetic research, for instance, as a giant waste of time: Sarah Palin was ticked off by the study of fruit flies, despite the fact that the guys studying fruit flies used the information to understand and prevent human birth defects, something that won them the Nobel Prize!

Studying something like this weird freak event may sound like a waste of time because it's a one of a kind ecosystem. But it has so much to tell us about the history of life, possible future changes in the earth with real consequences for human beings, and perhaps even a way for life to work on other planets. Sorry, Sarah, but the only real waste of resources is on ignorance.


  1. Thanks for enlightening once again. We can't afjord to remain ignorant to such phenomena.

  2. "Nature and nature's laws lay hid in ice

    God said, let 'EsperantoGrrl' be

    And there was light."


  3. I'm probably just crass as hell but my opinion is:

    Nature's laws hid in ice < Wooly mammoths hid in ice


  4. I would love to go there and paint landscapes!!!