SPATIO-TEMPORAL CHARACTERISTICS OF FUNGAL COMMUNITIES IN THE CHANGJIANG RIVER ESTUARY AND ITS ADJACENT SEA AREA
To understand the spatial-temporal distribution of fungal communities in the seawater of the Changjiang(Yangtze)River estuary and its adjacent waters,we investigated the variations in fungal abundance and community structure in surface and bottom seawater in the spring,summer and autumn of 2022 through an ITS rDNA absolute quantification and high-throughput amplicon sequencing.Results show that the fungal abundance significantly increased in autumn[surface:(3.02×108±6.09×107)copies/L;bottom:(2.56× 108±3.61 × 107)copies/L]compared to spring[surface:(1.38× 108±3.02×107)copies/L;bottom:(1.71×108±3.78×107)copies/L]and summer[surface:(1.14×108±3.64×107)copies/L;bottom:(1.11×108±2.55×107)copies/L,P<0.05].Although the difference between the surface and bottom seawater was not significant,it showed an offshore decaying pattern.The analysis of community structure revealed that the class Sordariomycetes of the phylum Ascomycota dominated in the seawater and the relative abundance significant increased in autumn.Diversity analysis indicated that there was significant seasonal variation in the fungal community.The diversity of fungal communities in surface and bottom seawater was inconsistent,with more pronounced seasonality in the bottom seawater.RDA analysis showed that the changes of fungal communities were influenced mainly by dissolved oxygen and temperature.Therefore,there were spatial-temporal variations in the fungal abundance and diversity in the estuary and its adjacent waters,which provide a basis for further in-depth analysis of the ecological functions of fungi in estuarine ecosystems.