Adaptive strategies of high and low nucleic acid prokaryotes in response to declining resource availability and selective grazing by protozoa  

作　　者：Chen HU Liuqian YU Xiaowei CHEN Jihua LIU Yao ZHANG John BATT Xilin XIAO Qiang SHI Rui ZHANG Tingwei LUO Nianzhi JIAO Dapeng XU 

机构地区：[1]College of the Environment and Ecology,Xiamen University,Xiamen 361102,China [2]State Key Laboratory of Marine Environmental Science,College of Ocean and Earth Sciences,Fujian Key Laboratory of Marine Carbon Sequestration,Xiamen University,Xiamen 361102,China [3]Joint Lab for Ocean Research and Education(LORE)of Dalhousie University,Canada,and Shandong University and Xiamen University,Xiamen 361102,China [4]Earth,Ocean and Atmospheric Sciences Thrust,The Hong Kong University of Science and Technology(Guangzhou),Guangzhou 510000,China [5]Institute of Marine Science and Technology,Shandong University,Qingdao 266237,China [6]Department of Oceanography,Dalhousie University,Halifax,Nova Scotia B3H 4R2,Canada [7]Institute for Advanced Study,Shenzhen University,Shenzhen 518060,China [8]Carbon Neutral Innovation Research Center,Xiamen University,Xiamen 361102,China

出　　处：《Science China Earth Sciences》2024年第6期1872-1884,共13页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.42188102,41861144018);the Natural Science Foundation of Fujian Province of China(Grant No.2023J05017);the Marine Economic Development Special Fund Project of Fujian Province of China(Grant No.FJHJF-L-2022-11);supported by the China Postdoctoral Science Foundation(Grant No.2021M691863);supported by the Innovation Team Project of Universities in Guangdong Province(Grant No.2023KCXTD028);supported by the Ph.D.Fellowship of the State Key Laboratory of Marine Environmental Science at Xiamen University。

摘　　要：Prokaryotes play a fundamental role in global ocean biogeochemical cycles.However,how the abundance and metabolic activity of ecologically distinct subgroups(i.e.,high nucleic acid(HNA)and low nucleic acid(LNA)cells),and their regulating factors,change in response to changing marine environmental conditions remains poorly understood.Here,we delved into the time-evolving dynamic responses of the HNA and LNA prokaryotic subgroups to declining resource availability and selective grazing by protozoa by conducting a 73-day incubation experiment in a large-volume(117,000 L)macrocosm that facilitates community-level exploration.We found that the metabolic activity of the HNA subgroup was higher than that of the LNA subgroup when the macrocosm was resource replete but that the HNA subgroup declined more rapidly than the LNA subgroup as the resources became increasingly scarce,leading to a steadily increasing contribution of LNA cells to prokaryotic activity.Meanwhile,as resources in the macrocosm became limited,protozoan grazing preference shifted from the HNA to the LNA subgroup and the contributions of the LNA subgroup to the carbon flow within the macrocosm increased.The findings highlight the resilience of LNA cells in resource-limited environments,illuminate the critical role of selective grazing by protozoa in balancing distinct prokaryotic subgroups under changing resource conditions,and demonstrate the complex and adaptive interactions between protozoa and prokaryotes across diverse environmental contexts.

关 键 词：Microbial loop Macrocosm experiment PROKARYOTE Top-down and bottom-up controls Carbon flow 

分 类 号：Q-0[生物学]