Mangroves are one of the most ecologically sensitive ecosystems to global climate change,which have cascading impacts on soil carbon(C),nitrogen(N)and phosphorus(P)cycling.Moreover,mangroves are experiencing increasin...Mangroves are one of the most ecologically sensitive ecosystems to global climate change,which have cascading impacts on soil carbon(C),nitrogen(N)and phosphorus(P)cycling.Moreover,mangroves are experiencing increasing N and P loadings and reduced oxygen availability due to intensified climate change and human activities.However,both direct and interactive effects of these perturbations on microbially mediated soil C,N and P cycling are poorly understood.Here,we simultaneously investigated the effects of N and P loadings and reduced oxygen on microbial biomass,microbial respiration,and extracellular enzyme activities(EEAs)in mangrove soils.We calculated the microbial metabolic quotient(qCO_(2)),which is regarded as a useful inverse metric of microbial C use efficiency(CUE).Our results show that reduced oxygen significantly increases both qCO_(2) and microbial specific EEAs(enzyme activity per unit of microbial biomass)for C-,N-and P-acquisition regardless of N or P loadings.Furthermore,we found that qCO_(2) positively correlated with microbial specific EEAs under reduced oxygen,whereas no clear relationship was detected under ambient oxygen.These results suggest that reduced oxygen increases microbial specific EEAs at the expense of increasing microbial respiration per unit biomass,indicating higher energy cost per unit enzyme production.展开更多
基金funding from EU H2020 Marie SkłodowskaCurie Actions(No.839806)Aarhus Universitets Forskningsfond(AUFF-E-2019-7-1)+3 种基金Danish Independent Research Foundation(1127-00015B)Nordic Committee of Agriculture and Food Researchsupported by Natural Environment Research Council(NERC)EAO Doctoral Training Partnership(NE/L002469/1)supported by a Ramon Areces Foundation research Fellowship and BBSRC Discovery Fellowship(BB/S010661/1).
文摘Mangroves are one of the most ecologically sensitive ecosystems to global climate change,which have cascading impacts on soil carbon(C),nitrogen(N)and phosphorus(P)cycling.Moreover,mangroves are experiencing increasing N and P loadings and reduced oxygen availability due to intensified climate change and human activities.However,both direct and interactive effects of these perturbations on microbially mediated soil C,N and P cycling are poorly understood.Here,we simultaneously investigated the effects of N and P loadings and reduced oxygen on microbial biomass,microbial respiration,and extracellular enzyme activities(EEAs)in mangrove soils.We calculated the microbial metabolic quotient(qCO_(2)),which is regarded as a useful inverse metric of microbial C use efficiency(CUE).Our results show that reduced oxygen significantly increases both qCO_(2) and microbial specific EEAs(enzyme activity per unit of microbial biomass)for C-,N-and P-acquisition regardless of N or P loadings.Furthermore,we found that qCO_(2) positively correlated with microbial specific EEAs under reduced oxygen,whereas no clear relationship was detected under ambient oxygen.These results suggest that reduced oxygen increases microbial specific EEAs at the expense of increasing microbial respiration per unit biomass,indicating higher energy cost per unit enzyme production.
