Chemical Properties Of A Microbially-Derived Fulvic Acid From A Hypereutrophic Coastal Pond In Antarctica
Cawley, Kaelin 1 ; McKnight, Diane 2 ; Fimmen, Ryan 3 ; Cory, Rose 4 ; Miller, Penney 5 ; Chin, Yu-Ping 6 ; Foreman, Christine 7
1 University of Colorado at Boulder
2 University of Colorado at Boulder
3 The Ohio State University
4 University of Colorado at Boulder
5 Rose Hulman Institute of Technology
6 The Ohio State University
7 Montana State University
We have been studying the chemistry of fulvic acids from Pony Lake, a hypereutrophic coastal pond in the McMurdo Sound region of Antarctica, beginning in 1992 and continuing until 2006. The chemical characteristics of the fulvic acid fractions isolated over this time period as well as the microbial community show remarkable consistency despite dramatic changes in physical conditions such as ice cover and timing of surface melt. We characterized the fulvic acid isolates based on elemental content, 1H/13C-NMR, UV-visible absorbance, and fluorescence spectra, carbon/nitrogen isotopic composition and GC-MS analysis of hydrolysis products. NMR and GC-MS techniques provide insights into the chemical structure of the fulvic acid showing that it contains functional groups derived from cellular structures as opposed to plant-derived structures like lignin. Absorbance and fluorescence spectra elucidate the dominant chemical and biological processes governing autochthonous fulvic acid production. During the summer of 2005-2006, a reference sample of Pony Lake was collected and will be made available to serve as a microbial end-member for distribution through the International Humic Substances Society.