Submersible tracks from the 2008 field season. Satellite image from Google Earth.
As the field season nears, and everyone is busy finishing up all those details necessary to make our time in the field run smoothly, it’s important to refocus on our science goals for this year.
To quickly recap last year’s field season : our science pilots managed to explore most of the lake, giving a wealth of video footage and personal observations for the entire science team to analyze during the past year. You can see just how much of the lake we covered last year from all the submarine tracks! For the 2009 field season we have two main goals: to finish exploring some of the areas that we didn’t reach last year (you never know what’s hiding in the dark!); and to explore in detail the areas that we found to be particularly fascinating from our analysis of the 2008 data.
Following-up on the extensive exploration from last year, we are turning our attention to understanding some of the already identified features and trends, and using these to answer some big questions. In the lake we find microbialite structures that vary in shape and size. Some lake bottom areas are covered with the microbialites, while others have just sediment, or algae, or rocks from landslides. So why is there such a variation in what we find in the lake? How do the microbialites form? What sets their shape, their size, their distribution? And what can they tell us about the preservation of biosignatures – the fossils of microorganisms? These are hard questions that geobiologists have been trying to answer for decades, and we think that studying Pavilion Lake will contribute to the understanding of microbialites throughout Earth’s history. To tackle these questions, this field season we will be using the DeepWorkers to get detailed imaging and data at previously identified areas of interest.
Microbialite structures among the chara (algae). Are the microbialites using the chara as a base to grow on?
Analysis of last year’s DeepWorker observations gave some surprising results, but also showed some possible trends that need to be investigated further. Last year we were surprised that the macro-morphology – the large-scale shape of the microbialite structures – was not strictly correlated with depth, like we thought it would be. So this year we hope that detailed observations needed to answer some smaller questions will ultimately help us answer our big questions. Some smaller questions we’re asking are: what are the microbialites growing on? Do they need a rock as a growing base, or algae, or do they just sit in the sediment? And does the growing medium have an effect on the shape or size of the microbialite? What about the small-scale structure (micro-morphology)? Microbialites with similar macro-morphologies can still be composed of differently shaped and sized components. The answers from all of these smaller questions will hopefully shed light on the bigger questions.
Every year we get some answers, and come up with even more questions. But that’s why this project is fascinating: Pavilion Lake is such a complex system! Little by little – by asking the right questions – the answers are coming together and we are starting to understand Pavilion Lake.
~Mars
