Scientific Reports 3, Article number: 1166 10.1038/srep01166 (2013); Published: January302013; Updated: March062013
The authors have noticed that in the original version of this Article, part of the Acknowledgements section was omitted. The additional acknowledgements appear below.
This work was funded by the National Science Foundation Antarctic Science Division (Office of Polar Programs) through grants to James W. Head (ANT-0739702) and David R. Marchant (ANT-0944702), which are gratefully acknowledged. Logistical support for this project in Antarctica was provided by the U.S. National Science Foundation through the U.S. Antarctic Program.