We've completed a circuit all the way around the lake, drilling 18 holes in a rough ring around the lake. Among other tasks, at each drill site we drop two cameras into the drill hole so we can see the microbial mats that grow on the bottom of the lake. We've been using the cameras to locate and understand variations in the mat communities. Sometimes the mats are flat, sometimes they are lumpy, and sometimes they grow in the webbed, pinnacled shapes that we are especially interested in exploring.
The flat microbial mats. Photo by Tyler Mackey.
Pinnacled mats. Photo by Tyler Mackey.
The main goal of our science is to better understand these webbed, pinnacled mats because they closely resemble the shapes of microbial communities from billions of years ago that are preserved in the rock record. In Lake Joyce these particular mats grow at a specific depth, but it's challenging to hit the right depth with our drill hole choices because this lake hasn't been very well studied. Sasha is using his GIS (Geographic Information Systems) skills to estimate lake depths using older aerial photos that show topography before the lake level rose.
Photos courtesy of USGS and Google images.
Another related goal of all of our exploratory drilling is to choose the right place to melt a dive hole. In the near future, Tyler and Ian will dive into the lake to see the mat community firsthand in much more detail than what we can see with the cameras. We've narrowed in on a spot near a small delta, where we are likely to see the influence of sedimentation on the mat communities. The delta is fed by a small, seasonal stream that carries sand and grit into the lake.
Within the next couple of days, we'll get our dive tent set up, and we'll melt the dive hole. I'll show you more as it unfolds!
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