Our Science Goals
A fair amount of our time together as a team has been spent making sure we all know what the research goals are for this field season. Tyler has spent months planning for our investigations, and while there are countless questions that we could focus on, here's what we're doing:
THE REALLY BIG "So What?"
Ultimately, we hope to discover more about what early Earth was like about 2.5 billion years ago. Around that time, our planet was in a transitional time when free oxygen was building up in our atmosphere because of photosynthesis from cyanobacteria, allowing for other life forms to evolve later. What were early communities of single-celled organisms like? How did they grow and develop? While we'd love to answer all of these questions, it isn't possible to do in just one field season, so Tyler's narrowed the focus to one key part of this:
OUR Big Question for the field season
How does sedimentation affect mat morphology? In other words, how is the shape of the mats affected by deposition of sand and silt from nearby melting glaciers? We are going to focus on just one mat shape — the mats that grow into webbed pinnacles. We predict that in places with more sedimentation, there will be fewer pinnacled mats. (Remember that these modern mats resemble ones preserved in the rock record from 2.5 billion years ago.)
Increases in glaciers melting in recent years may bring influx of sediment with it. Courtesy of Ian Hawes.
Our Process
Over the course of the seven weeks we'll be out in the field, we plan the following activities:
Drill approximately 30 holes in the ice so we can lower cameras in to look around and collect mat samples. We'll be collecting data about everything we see, but in particular, we'll be looking for those webbed, pinnacled mats. Tyler predicts that they should be growing in a "bathtub ring" shape around the lake at a depth of 15 meters.
We'll drill more holes in the ice and place 8 sediment traps. The placement will be chosen for variety — some places with little sedimentation, some with lots so that we can see what differences there are in mat growth as a result.
LTER Limno B505 drilling operations at Lake Fryxell.
- On about November 17, we'll be joined by two more team members, including Ian Hawes, who's a diver like Tyler. Once Tyler has a dive-mate, we'll melt a large hole in the ice so that Ian and Tyler can take turns diving in the lake. They'll be able to take more samples of both mats and sediment as well as take measurements of light levels and water chemistry at the interface between mat and water.
Scientists melting a hole large enough for a diver.
In conclusion....
There are many peripheral questions we will also be collecting data in order to answer, but these are the big ones and our process for exploring them. As with all science, observations always lead to more questions for those with a curious mind. Because the discovery of these mats is relatively recent, there's much to be investigated about them in the future!
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