| Popis: |
The high temperature and rainy climate conditions make the diatom community in tropical freshwater ecosystem significantly different from other regions, which has specific laws and differences. Taking the diatom community structure of Wanquan River in Hainan Island as the research object, the regularity and difference factors were analyzed. In this study, 18 water samples were collected from 9 sampling sites in Wanquan River of Hainan Island in dry season (February) and wet season (August). High-throughput sequencing of eukaryotic plankton in water samples was carried out by using 18S rDNA meta-barcoding, and diatom classification information was extracted from each sampling point in different seasons. In this study, a total of 67 species, 38 genera, 7 families, 5 orders, 4 classes of diatoms were obtained. The dominant diatoms in Wanquan River were Mediophyceae and Bacillariophyceae. According to Alpha and Beta analysis, the total number and species of diatom in dry season were more, and the diatom community difference in each sampling site was also greater than those in wet season. There were five diatom species with significant differences between two seasons (P > 0.05),,Thalassiosira, Guinardia, Gomphonema, Mediophyceae and Discostella. In addition, the influence degree and trend of different environmental variables on diatom community composition were also analyzed. Three environmental variables, temperature, wind speed and water temperature, had the greatest impact on the diatom community. Dissolved oxygen, chromium ion and total alkalinity, also had a certain impact on the diatom community distribution. The diatom community structure and influencing factors in tropical fresh water differs greatly from that in other regions. |
