SREL Reprint #2563

 

 

 

Changes in fatty acid and hydrocarbon composition of leaves during decomposition in a southeastern blackwater stream

Gary L. Mills1, J. Vaun McArthur1, Charlotte Wolfe2, John M. Aho3, and Russell B. Rader4

1Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, South Carolina 29802, USA
2School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana 47450, USA
3Department of Biology, Auburn University at Montgomery, Montgomery, Alabama 36117, USA
4Department of Zoology, Brigham Young University, Provo, Utah 84602, USA

Abstract: Fatty acid and hydrocarbon composition were determined in decomposing leaf packets of sweetgum (Liquidambar styraciflua) and water oak (Quercus nigra) from a snag habitat in a southeastern blackwater stream. The initial total fatty acid and hydrocarbon concentrations in sweetgum leaves were significantly greater than in the oak species. Higher concentrations of unsaturated fatty acids and dicyclic diterpenoid hydrocarbons accounted for most of this difference. Both of these biochemical subgroups are preferentially degraded relative to the bulk leaf material and other compounds within their respective lipid classes. No significant differences remained after 70 days of decomposition. Cuticular fatty acids are selectively preserved and thus, increased relative to noncuticular components during decomposition. The bacterially derived iso- and anteiso-branched-chain fatty acids increased markedly after 23 days. The results of this study suggest that qualitative differences in lipid composition may contribute to the observed difference in overall decomposition rate of leaves between these species.

Keywords: Decomposition, oak leaves, sweetgum leaves, biochemical composition

SREL Reprint #2563

Mills, G. L., J. Vaun McArthur, C. Wolfe, J. M. Aho, and R. B. Rader. 2001. Changes in fatty acid and hydrocarbon composition of leaves during decomposition in a southeastern blackwater stream. Arch. Hydrobiol. 152:315-328.

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