Effects of urbanization on fungal communities and their functions in the sediment of the Haihe River.

Purpose: Urbanization can severely damage the river ecosystem. This study investigated the effects of various types of urbanization, such as urban human activities, pollution by the chemical industry, port industry, and fungal communities in the sediment from the Haihe River to the Bohai Sea Estuary. Materials and methods: Based on the metagenomic sequencing results, the impact of urbanization on the river ecosystem in terms of fungal communities' composition, diversity, and function potential in the sediment was studied. Results and discussion: The results showed that the sediment in the urban area accumulated large amounts of N, P, and PAHs, thus increasing the abundance of the fungal genera Beauveria, Verticillium, Metarhizium, Tolypocladium, Tuber, and Coccidioides but decreasing the relative abundance of key rate-limiting enzymes in the pentose phosphate pathway while increasing the relative abundance of sulfur-activated genes. The effect of industrial pollution on the sediment was mainly reflected in the increase of salinity. In terms of fungal functions, industrial pollution inhibited the pentose phosphate pathway but promoted the sulfur reduction function. In addition, the content of salinity and nitrate nitrogen was relatively high but the fungal diversity was low in the port and estuary areas. KEGG results demonstrated that the fungi of these two sample areas had high glycolytic functions. Conclusions: The fungal community composition and function in the sediment of the Haihe River were reshaped under different urbanization types, suggesting the negative impact of urbanization on the river ecosystem and also providing a basis for the management and restoration of the sediment of the Haihe River. [ABSTRACT FROM AUTHOR]