Mechanism and driving factors of phytoplankton community construction in the lower rea-ches of Yarlung Zangbo River
In order to explore phytoplankton community diversity and its driving factors in the lower reaches of the Yarlung Zangbo River,phytoplankton samples were collected at 34 sites in May 2022(spring),July 2023(summer)and September 2023(au-tumn).Phytoplankton species were identified by microscopy.Environmental factors during the studied period were investigated.Based on the measured data,the phytoplankton community structure was characterized.The diverse phytoplankton community in different seasons and its driving factors were explored.The results showed that:1)a total of 269 species and varieties of phyto-plankton were identified,belonging to 8 phyla,10 classes,22 orders,40 families and 87 genera.The order of cell abundance was spring＞summer＞autumn.the order of species number was autumn＞spring＞summer.The phytoplankton community structure as a whole showed diatom-green algae-cyanobacteria type.Twelve dominant species were selected,all of which were diatoms.2)Shan-non diversity index,Pielou evenness index,Simpson diversity index and Margalef richness index were lowest in summer.The prin-cipal coordinate analysis results showed that there were seasonal variations in phytoplankton community composition.By analyzing βdiversity and component decomposition of these three seasons,we found that this difference was mainly due to turnover,in particu-larly in spring.3)The neutral community model and the corrected random rate showed that the random process dominated the dy-namics of phytoplankton communities in the lower reaches of the Yarlung Zangbo River in these three seasons.The variance decom-position analysis showed that the explanation rate of geographic factors(10.13％)was greater than that of environmental factors(7.46％).Latitude and altitude were the main geographic factors affecting the dynamics of phytoplankton communities.Water tem-perature was the main environmental factor affecting the dynamics of phytoplankton community.4)The results of cooccurrence net-work analysis showed that phytoplankton interaction was mainly cooperative.The community structure in autumn was more concise and stable than that in spring and summer.
Phytoplanktoncommunity diversityneutral modelmodified stochsticity ratiostochastic processdriving factorsthe lower reaches of Yarlung Zangbo River
万方数据
维普
