Ok, Really, Why Am I Freezing?

As you have probably noticed by now, it takes a huge amount of work and investment to get to the Dry Valleys. So why are we bothering? What is the point? Why should anyone care? And from my perspective, what is worth being so unbelievably cold for two months!?

There are two basic answers to these questions. The first - we are driven to explore the world around us!

Exploration allows us to make discoveries that are impossible to predict. Many of the scientific discoveries that have completely changed the world came as a complete surprise. Although all scientific work builds upon the work done by others who have come before, you never know which step will be revolutionary!

Lake Joyce has been the subject of very little exploration. Only 2 or 3 SCUBA dives have ever been done in the lake, and very little science has been done. We cannot possibly predict all the mysterious things that we will discover below the ice, so we are here to have a look!

The second answer to why we are bothering to come all they way out to the Dry Valleys is - we are interested in understanding the evolution and distribution of life in the universe.

Yeah, that is a big goal. Don’t worry, we are not the only folks working on it! It is, in fact, one of the driving goals of the field of Exobiology. There is a possibility that life is quite abundant in the universe, but before we can understand or even search successfully for it, we need to understand the origin and evolution of life here on Earth. There are a couple of main reasons that Lake Joyce can help us with this!

Extreme Environments
Extreme environments are areas in which the daily conditions are far more extreme than what we find in most places on Earth. For example, they might be places of extreme temperature, of extreme pressure, or of extreme chemistry. Extreme environments are places in which you would hardly expect to find life, and yet time and time again, we do find life eeking out a meager existence or sometimes even flourishing is such environments. If we are trying to decide where to search for life elsewhere in the universe, you can probably guess why studying life in extreme environments will be useful! Most of the other planets, asteroids, and comets in our solar system, and probably farther out in the universe are places that host extreme environments when compared to the habitats we are familiar with on Earth. However, we are learning that life can find a hold in many diverse extreme environments on this planet, so it is not so ridiculous to think that life may find a way to evolve and exist off-world.

Lake Joyce definitely counts as an extreme environment! The lake is covered with 4-7 meters of ice all year round. The water temperature is only just above freezing: around 1 degrees C or 33 degrees F. During the summer months, the lake receives 24 hours of sunlight, while in the winter, the lake sits through 24 hours of darkness. Imagine trying to grow anything in those conditions! Yet, the bottom of the lake is home to extensive microbial mats! Microbes are single-celled organisms such as bacteria, archea, or single-celled eukaryotes (people are eukaryotes, so this last category is full of organisms closely related to you, but consisting only of one cell. Giardia is a good example). Microbial mats are, thus, what they sound like: mats or communities of small, usually single-celled organisms. In Lake Joyce, one of the most important inhabitants of the microbial mats is a type of cyanobacterial. Cyanobacteria are quite famous for inventing the type of photosynthesis that produces oxygen. If cyanobacterial had never evolved, the Earth would not have an atmosphere full of oxygen, and you would have a great deal of difficulty breathing. Plants such as grasses and trees actually inherited the ability to do photosynthesis from cyanobacteria! Cool! So, you might have trouble gardening at the bottom of Lake Joyce due to the extreme conditions, but the communities of cyanobacterial are thriving. Naturally, we are very interested in understanding just how they are so happy!

Life on Early Earth
Another benefit of studying microbial communities in extreme environments is that there are not very many metazoans (organisms with multiple cells) around. Don’t get me wrong – I enjoy multi-celled organisms as much as the next person. I am, in fact, quite fond of my cats. However, I am interested in understanding the early evolution of life on Earth. It turns out that multi-celled organisms are really quite young. For most of Earth history, the planet was inhabited only by single-celled critters, usually living in communities like microbial mats. There are many places in the world in which I can study microbial mats (and I do), however making comparisons between those modern systems and ancient Earth can be troublesome. For example, many of the microbial mats I study are constantly being torn apart and eaten by snails and fish! Snails and fish didn’t evolve until between 400-500 million years ago, but there were microbial mats on the planet for at least 3.5 billion years before that! You get the idea… Here in Lake Joyce, this sort of a problem will not be nearly so pronounced!

In fact, because Lake Joyce is such a restricted environment, we expect to be able to study the shapes of the microbial communities in great detail. In order to understand the early evolution of microbial mats on Earth, we look at the fossil record of these mats. Although there are many details preserved in the rocks, the most obvious feature preserved is the shape of the microbial communities. By understanding the ways in which such shapes are created in modern environments, we can better interpret the ancient examples. So, in a way, diving in Lake Joyce will be like looking back in time 3 or 4 billion years! I’m still waiting for a time machine to be invented, but this will do while I wait!

See, all this really is worth freezing for!