HR: 1330h
AN: NB33I-14    [Abstracts]
TI: Influence of Leaf Chemical Composition on Bacterial and Fungal Colonization During Leaf Litter Decomposition in a Venezuelan stream
AU: * Rincon, J
EM: jorincon@luz.edu.ve
AF: Lab. Contaminacion Acuatica, Dpto. Biologia, Universidad del Zulia., Apartado 15247, Maracaibo 4005-A, Estado Zulia, Maracaibo, Zul Venezuela
AB: We studied bacterial and fungal colonization during decomposition of leaf litter differing in chemical composition in a small intermittent stream of northwestern Venezuela. Litter bags containing leaves of Tabebuia roseae, Ficus sp, Hura crepitans and Anacardium excelsum were incubated during 42 days in the stream. Six bags were retrieved after 2, 7, 14, 21, 28, 35 and 42 days and the mass loss was registered. Leaves were initially analyzed for N, P, Lignin and Polyphenols in order to assess the chemical composition of each species. Conidia of aquatic hyphomycetes were identified and quantified after in vitro incubation of leaves with filtered stream water. Bacteria were counted and identified using an epifluorescence microscope. The species H. crepitans and Ficus sp showed higher decomposition rates than T. roseae and A. excelsum. Higher conidia production was observed in Anacardium leaves, while bacterial density and biomass resulted higher in Hura leaves. Our results suggest that chemical composition of leaves differentially affected to bacteria and aquatic hyphomicetes colonization. Bacteria colonized earlier than fungi during leaf litter decomposition process.
DE: 9810 New fields (not classifiable under other headings)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly