Dry Valley Tour: Part I
It always surprises people to learn that lakes exist in Antarctica. Well they do, but they’re few and far between. The McMurdo Dry Valleys remain unglaciated because they are situated in a rain shadow of the Transantarctic Mountains. The valleys are cold enough to be covered by a giant ice sheet, but the lack of precipitation, only 3-50 mm a year, keeps the Valleys dry and beautiful.
This area is made up of a mosaic of polar desert landforms, and is one of the most spectacular, breathtaking landscapes on Earth. However, there are a few features that are so bizzare and captivating that the Dry Valleys sometimes feel like another planet. We’re lucky enough to work beside them day after day, and it’s high time we explore them.
For the last week, we’ve been sampling gases from the West Lobe of Lake Bonney. The lake is abutted by Taylor Glacier, which is an extension of the East Antarctic Ice Sheet. Where the glacier hits the lake, there is a unique feature called ‘Blood Falls’.
Blood Falls was originally thought to be formed by algae, but is in fact iron-rich hypersaline water that is sourced from hundreds of meters below the glacier.
One of our colleagues in Antarctica, Jill Mikucki, has extensively studied the biogeochemistry of the system. It is believed that iron is accumulated through a microbially mediated pathway that uses sulfur as a catalyst. Future work is planned to investigate the source of Blood Falls beneath Taylor Glacier. Until then, enjoy the specatular view!