Effects of Zn, Fe and Mn on leaf litter breakdown by aquatic fungi: a microcosm study
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Medeiros, Adriana | Duarte, Sofia Alexandra Ferreira | Pascoal, Cláudia | Cássio, Fernanda | Graça, Manuel
We investigated the effects of heavy metals on leaf litter decomposition in streams. Leaves were immersed (10 days) at a reference (R) and a metal-impacted (I) site and exposed in microcosms with increased Zn, Mn or Fe content, and to stream water from site R or I. Fungal biomass was higher in microcosms with leaves colonized at I and water from R. Fungal sporulation was higher in microcosms with leaves and water from R. Concentrations of 4.9, 9.6 and 5 ppm of Zn, Mn and Fe decrease fungal sporulation. The number of fungal species (spore counts and DGGE fingerprints) was lower in leaves colonized at site I. Cluster analyses of DGGE showed that Fe was the metal that most altered the structure of fungal community. Our results suggest that metal pollution affect leaf-associated fungi depending on metal identity and concentration, and effects appear to be less pronounced in metal-adapted communities.
显示更多 [+] 显示较少 [-]This project was funded by the European Union, through the Contract EVK1-CT-2001-00088 (Project RivFunction) and by the Portuguese Foundation for Science and Technology FCT (POCTI/BSE/34024/00). ADRIANA MEDEIROS received a grant from CAPES (2006 Processo n degrees 2696/05-3) and SOFIA DUARTE received a grant from FCT (SFRH/BD/13482/2003). We thank ELSA RODRIGUES and ARANCHA MARCOTEGUI for field and laboratorial assistance and JOAO PRATAS for quantification of heavy metals.
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