Pelagic-benthic coupling of the microbial food web modifies nutrient cycles along a cascade-dammed river  

作　　者：Nan Yang Linqiong Wang Li Lin Yi Li Wenlong Zhang Lihua Niu Huanjun Zhang Longfei Wang 

机构地区：[1]Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education,College of Environment,Hohai University,Nanjing 210098,China [2]College of Oceanography,Hohai University,Nanjing 210098,China [3]Department of Basin Water Environment,Changjiang River Scientific Research Institute,Wuhan 430010,China [4]Hubei Provincial Key Laboratory of Basin Water Resources and Ecological Environment Sciences,Changjiang River Scientific Research Institute,Wuhan 430010,China

出　　处：《Frontiers of Environmental Science & Engineering》2022年第4期125-137,共13页环境科学与工程前沿（英文）

基　　金：This work was supported by the National Natural Science Foundation of China(Grant Nos.51779076 and 51879079).

摘　　要：Cascade dams disrupt the river continuum,altering hydrology,biodiversity and nutrient flux.Describing the diversity of multi-trophic microbiota and assessing microbial contributions to the ecosystem processes are prerequisites for the restoration of these aquatic systems.This study investigated the microbial food web structure along a cascade-dammed river,paying special attention to the multi-trophic relationships and the potential role of pelagic-benthic coupling in nutrient cycles.Our results revealed the discontinuity in bacterial and eukaryotic community composition,functional group proportion,as well as a-diversity due to fragmentation by damming.The high microbial dissimilarity along the river,with the total multi-trophic P-diversity was 0.84,was almost completely caused by species replacement.Synchronization among trophic levels suggests potential interactions of the pelagic and the benthic groups,of which the p-diversities were primarily influenced by geographic and environmental factors,respectively.Dam-induced environmental variations,especially hydrological and nutrient variables,potentially influence the microbial food web via both top-down and bottom-up forces.We proposed that the cycles of carbon,nitrogen and phosphorus are influenced by multi-trophic groups through autotrophic and heterotrophic processes,predator-prey relationships,as well as the release of nutrients mainly by microfauna.Our results advance the notion that pelagic-benthic trophic coupling may intensify the accumulation of organic carbon,ammonium and inorganic phosphorus,thereby changing the biogeochemical patterns along river systems.As a consequence,researchers should pay more attention to the multi-trophic studies when assessing the environmental impacts,and to provide the necessary guidance for the ecological conservation and restoration of the dam-regulated systems.

关 键 词：RESERVOIR Multi-trophic Beta diversity PREDATOR-PREY Nutrient accumulation 

分 类 号：X55[环境科学与工程—环境工程]