Acknowledgments

The authors thank the following people for their contributions to this work: Chauncey Anderson, Amy Brooks, Kurt Carpenter, Micelis Doyle, Wes Jarrell, Matt Johnston, and Tammy Wood for assistance in sample collection; Renate Ryan for assistance in not only sample collection but also processing and freeze-drying; Carol Kendall and the graduate and post-doctoral students in her stable isotopes laboratory for the many hours spent analyzing samples from this study and their help in interpreting the laboratory data; and Jan Miller of Clean Water Services for helping to organize and fund the project. Finally, the authors are grateful to the group of reviewers that provided helpful comments on this report.

First posted August 17, 2010