Department of Biology, Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
Arch Environ Contam Toxicol. 2011 Aug;61(2):211-9. doi: 10.1007/s00244-010-9610-6. Epub 2010 Oct 19.
Urbanization and industrial activities have contributed to widespread contamination by metals and polycyclic aromatic hydrocarbons, but the combined effects of these toxics on aquatic biota and processes are poorly understood. We examined the effects of cadmium (Cd) and phenanthrene on the activity and diversity of fungi associated with decomposing leaf litter in streams. Leaves of Alnus glutinosa were immersed for 10 days in an unpolluted low-order stream in northwest Portugal to allow microbial colonization. Leaves were then exposed in microcosms for 14 days to Cd (0.06-4.5 mg L(-1)) and phenanthrene (0.2 mg L(-1)) either alone or in mixture. A total of 19 aquatic hyphomycete species were found sporulating on leaves during the whole study. The dominant species was Articulospora tetracladia, followed by Alatospora pulchella, Clavatospora longibrachiata, and Tetrachaetum elegans. Exposure to Cd and phenanthrene decreased the contribution of A. tetracladia to the total conidial production, whereas it increased that of A. pulchella. Fungal diversity, assessed as denaturing gradient gel electrophoresis fingerprinting or conidial morphology, was decreased by the exposure to Cd and/or phenanthrene. Moreover, increased Cd concentrations decreased leaf decomposition and fungal reproduction but did not inhibit fungal biomass production. Exposure to phenanthrene potentiated the negative effects of Cd on fungal diversity and activity, suggesting that the co-occurrence of these stressors may pose additional risk to aquatic biodiversity and stream ecosystem functioning.
城市化和工业活动导致金属和多环芳烃广泛污染，但这些毒物对水生生物群和过程的综合影响还知之甚少。我们研究了镉 (Cd) 和菲对溪流中分解落叶相关真菌的活性和多样性的影响。将欧洲桤木 (Alnus glutinosa) 的叶子在葡萄牙西北部未受污染的低阶溪流中浸泡 10 天，以允许微生物定殖。然后，将叶子在微宇宙中暴露于 Cd（0.06-4.5mg/L）和菲（0.2mg/L）中 14 天，单独或混合暴露。在整个研究过程中，共有 19 种水生丝孢菌在叶子上产孢。优势种是四节孢属 (Articulospora tetracladia)，其次是美丽节丛孢属 (Alatospora pulchella)、长柄双曲孢属 (Clavatospora longibrachiata) 和拟青霉属 (Tetrachaetum elegans)。Cd 和菲的暴露降低了 A. tetracladia 对总分生孢子产生的贡献，而增加了 A. pulchella 的贡献。真菌多样性，通过变性梯度凝胶电泳指纹图谱或分生孢子形态评估，Cd 和/或菲的暴露降低了真菌多样性。此外，增加的 Cd 浓度降低了叶片分解和真菌繁殖，但并没有抑制真菌生物量的产生。暴露于菲增强了 Cd 对真菌多样性和活性的负面影响，表明这些胁迫物的共同存在可能对水生生物多样性和溪流生态系统功能构成额外风险。
