Highlighting patterns of fungal diversity and composition shaped by ocean currents using the East China Sea as a model.

How ocean currents shape fungal transport, dispersal and more broadly fungal biogeography remains poorly understood. The East China Sea (ECS) is a complex and dynamic habitat with different water masses blending microbial communities. The internal transcribed spacer 2 region of fungal rDNA was analysed in water and sediment samples directly collected from the coastal (CWM), Kuroshio (KSWM), Taiwan warm (TWM) and the shelf mixed water mass (MWM), coupled with hydrographic properties measurements, to determine how ocean currents impact the fungal community composition. Almost 9k fungal operational taxonomic units (OTUs) spanning six phyla, 25 known classes, 102 orders and 694 genera were obtained. The typical terrestrial and freshwater fungal genus, Byssochlamys, was dominant in the CWM, while increasing abundance of a specific OTU affiliated with Aspergillus was revealed from coastal to open ocean water masses (TWM and KSWM). Compared with water samples, sediment harboured an increased diversity with distinct fungal communities. The proximity of the Yangtze and Qiantang estuaries homogenizes the surface water and sediment communities. A significant influence of ocean currents on community structure was found, which is believed to reduce proportionally the variation explained by environmental parameters at the scale of the total water masses. Dissolved oxygen and depth were identified as the major parameters structuring the fungal community. Our results indicate that passive fungal dispersal driven by ocean currents and river run-off, in conjunction with the distinct hydrographic conditions of individual water masses, shapes the fungal community composition and distribution pattern in the ECS.

[Diversity and niche of soil moniliaceous hyphomycetes in Taibai Mountain].

Sixteen genera of soil moniliaceous hyphomycetes were isolated from 40 soil samples collected from the southern and northern slopes of Taibai Mountain, and the indices Shannon-Wiener diversity index, evenness, niche breadth, and niche overlap were used to analyze the community structure and niche of soil moniliaceous hyphomycetes in different forest types on the southern and northern slopes of Taibai Mountain. The results showed that the distribution of soil moniliaceous hyphomycetes on the study area had an obvious environmental gradient pattern. Altitude and forest type were the main determinants of the fungal community distribution. The species richness and diversity index of soil moniliaceous hyphomycetes decreased significantly with increasing altitude, but the community evenness represented an increasing trend. Among the genera of soil moniliaceous hyphomycetes, Penicillium, Aspergillus, Verticillium, Paecilomyces and Acremonium had larger niche width and greater niche overlap with other genera, suggeting that these genera had wide distribution on the southern and northern slopes of Taibai Mountain. As for Trichothecium, Gliocladium and Metarhizium, their niche width was narrower, and their niche overlap with other genera was smaller, indicating that the distribution of these genera was more affected by altitude and vegetation, with the occurrence only in special forest types.

Diversity analysis of soil dematiaceous hyphomycetes from the Yellow River source area: I.

Twenty-four soil samples of eight ecosystem-types around the Yellow River source area were investigated for the number and specific composition of soil dematiaceous hyphomycetes by dilution plate technique. And then the co-relationship between genus species of soil dematiaceous hyphomycetes and ecosystem-types was analyzed. The results show that the amount and species distribution of soil dematiaceous hyphomycetes had an obvious variability in different ecosystem-types, and that the dominant genus species varied in the eight ecosystem-types studied, with Cladosporium being the dominant genus in seven of the eight ecosystem-types except wetland. The index of species diversity varied in different ecosystem-types. The niche breadth analysis showed that Cladosporium had the highest niche breadth and distributed in all ecosystem-types, while the genera with a narrow niche breadth distributed only in a few ecosystem-types. The results of niche overlap index analysis indicated that Stachybotrys and Torula, Doratomyces and Scolecobasidium, Cladosporium and Chrysosporium had a higher niche overlap, whereas Arthrinium and Gliomastix, Phialophora and Doratomyces, Oidiodendron and Ulocladium had no niche overlap.