Treseder Kathleen K
Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.
Ecol Lett. 2008 Oct;11(10):1111-20. doi: 10.1111/j.1461-0248.2008.01230.x. Epub 2008 Jul 30.
Nitrogen (N) enrichment is an element of global change that could influence the growth and abundance of many organisms. In this meta-analysis, I synthesized responses of microbial biomass to N additions in 82 published field studies. I hypothesized that the biomass of fungi, bacteria or the microbial community as a whole would be altered under N additions. I also predicted that changes in biomass would parallel changes in soil CO2 emissions. Microbial biomass declined 15% on average under N fertilization, but fungi and bacteria were not significantly altered in studies that examined each group separately. Moreover, declines in abundance of microbes and fungi were more evident in studies of longer durations and with higher total amounts of N added. In addition, responses of microbial biomass to N fertilization were significantly correlated with responses of soil CO2 emissions. There were no significant effects of biomes, fertilizer types, ambient N deposition rates or methods of measuring biomass. Altogether, these results suggest that N enrichment could reduce microbial biomass in many ecosystems, with corresponding declines in soil CO2 emissions.
氮（N）富集是全球变化的一个因素，它可能影响许多生物的生长和数量。在这项荟萃分析中，我综合了82项已发表的田间研究中微生物生物量对氮添加的响应。我假设在添加氮的情况下，真菌、细菌或整个微生物群落的生物量会发生变化。我还预测生物量的变化将与土壤二氧化碳排放量的变化平行。在施氮条件下，微生物生物量平均下降了15%，但在分别研究每组的研究中，真菌和细菌没有显著变化。此外，在持续时间较长和添加氮总量较高的研究中，微生物和真菌数量的下降更为明显。此外，微生物生物量对施氮的响应与土壤二氧化碳排放的响应显著相关。生物群落、肥料类型、环境氮沉降速率或生物量测量方法没有显著影响。总之，这些结果表明，氮富集可能会减少许多生态系统中的微生物生物量，同时土壤二氧化碳排放量也会相应下降。
