Visions of Earth's Early Biosphere


Pictured above are the photosynthetic microbial mats present on the bottom of Lake Untersee. The large cone-like structures, the smaller cupsate pinnacles, and flat mats are composed of filamentous cyanobacteria dominated by Leptolybya and Phormidium. As far as we know, this is the only location on Earth where, in a modern ecosystem, large conical stromatolites are forming as they did billions of years ago on early Earth. Photo credit: Dale T. Andersen ©2013

Throughout Earth’s history, microbial communities have found refuge in nearly every environment on Earth including those that most other life would find to be extreme and inhospitable. In the absence of large muliticellular life, these microorganisms will form emergent structures with varying sizes, shapes, textures, and pigments, and in the fossil record one can find many examples of these ancient ecosystems, some dating back almost 3.5 billion years. However about 550 million years ago more complex, multicellular life evolved – life that could crawl, burrow, and graze, which resulted in the disruption of these microbial communities and fewer examples being preserved in the sedimentary record.

To find these structures today one must travel to places where the physical and chemical environments are simply too harsh for the more typical, modern multicellular organisms to tolerate, but just right for the microbial communities to flourish. One such place is Lake Untersee - the largest (11.4 km2) and deepest (>170 m) freshwater lake in East Antarctica.

Dale diving

Dr. Dale Andersen led a team of researchers to Lake Untersee in November-December 2012. There they conducted a series of studies aimed at describing the physical, chemical, and biological aspects of the lake, and to sample the microbial life found in the lake’s water column and bottom sediments. Because climate plays such an important role with regulating the ecosystem, Dr. Andersen and his team collected data from an automated meteorological station he had deployed during an earlier expedition in 2008. The station collects a variety of basic weather elements such as air temperature, humidity, wind speed/direction, solar radiation, etc. The data will be used to model the physical environment, and in the long-term the data will play an important role in monitoring global climate change for this region of Antarctica.

Following the work at Lake Untersee, the team returned to Cape Town, South Africa, in late December, and afterwards, they took home the data and samples collected and began the process of analyzing them and reducing the data for publication in the scientific literature, and sharing the results with the public.

What are a few of the challenges faced by Dr. Andersen and his team, apart from living and working in an extremely remote and harsh environment like Antarctica? Mostly it is the search for the financial support to keep projects such as this moving forward.

Donations are important sources of funding for our work and these funds help insure the success of our research efforts - your contributions are important to help us carry out our work in Antarctica.

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