Abstract
Fungal communities perform essential functions in biogeochemical cycles. However, knowledge of fungal community structural changes in river ecosystems is still very limited. In the present study, we combined culture-dependent and culture-independent methods to investigate fungal distribution and diversity in sediment on a regional scale in the Songhua River catchment, located in North-East Asia. A total of 147 samples over the whole river catchment were analyzed. The results showed that compared to the mainstream, the tributaries have a higher fungal community organization and culturable fungal concentration, but possess lower community dynamics as assessed by denaturing gradient gel electrophoresis (DGGE). Furthermore, phylogenetic analysis of DGGE bands showed that Ascomycota and Basidiomycota were the predominant community in the Songhua River catchment. Redundancy analysis revealed that longitude was the primary factor determining the variation of fungal community structure, and fungal biomass was mainly related to the total nutrient content. Our findings provide new insights into the characteristics of fungal community distribution in a temperate zone river at a regional scale, and demonstrate that fungal dispersal is restricted by geographical barriers in a whole river catchment.
Highlights
Sediment and their attached microbes make a substantial contribution to the biogeochemical processes of river ecosystems (Rastogi et al, 2011; Sanchez-Andrea et al, 2011), such as nutrient transformations, energy flow, food web and self-purification (Gerbersdorf et al, 2011)
It was concluded that arbuscular mycorrhizal fungi (AMF) community composition is significantly changed with the geographical distance at the regional scale (250 km), while environmental heterogeneity was the major factor in determining turnover of AMF taxa at the landscape scale
The fungal community structure, composition and their response to extrinsic factors were investigated in the sediment of the whole Songhua River catchment at the succession and regional scale using both culture independent and dependent techniques
Summary
Sediment and their attached microbes make a substantial contribution to the biogeochemical processes of river ecosystems (Rastogi et al, 2011; Sanchez-Andrea et al, 2011), such as nutrient transformations, energy flow, food web and self-purification (Gerbersdorf et al, 2011). The driving factors of microbial community, which maintain biodiversity on the Fungal diversity in freshwater sediment earth, have mainly been discussed in terms of contemporary disturbances (environmental heterogeneity) and historical contingencies (geographical distance) (Green and Bohannan, 2006; Ge et al, 2008; Vanormelingen et al, 2008; Schauer et al, 2010; Lindstrom and Langenheder, 2012; Hazard et al, 2013; Wu et al, 2013). It was concluded that arbuscular mycorrhizal fungi (AMF) community composition is significantly changed with the geographical distance at the regional scale (250 km), while environmental heterogeneity was the major factor in determining turnover of AMF taxa at the landscape scale (van der Gast et al, 2011).
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