Trade-off between microbial carbon use efficiency and specific nutrient-acquiring extracellular enzyme activities under reduced oxygen

• Reduced oxygen increased microbial metabolic quotient (qCO2). enhanced specific C-, N- and P-acquiring enzyme activity. C relative to N P limitation. Specific activity was positively related qCO2 under reduced oxygen. Mangroves are one of the most ecologically sensitive ecosystems global climate change, which have cascading impacts on soil carbon (C), nitrogen (N) phosphorus (P) cycling. Moreover, mangroves experiencing increasing loadings availability due intensified change human activities. However, both direct interactive effects these perturbations microbially mediated C, cycling poorly understood. Here, we simultaneously investigated biomass, respiration, extracellular activities (EEAs) in mangrove soils. We calculated (qCO2), is regarded as a useful inverse metric use efficiency (CUE). Our results show that significantly increases EEAs (enzyme per unit biomass) for P-acquisition regardless or loadings. Furthermore, found correlated with oxygen, whereas no clear relationship detected ambient These suggest at expense respiration indicating higher energy cost production.