Labile, recalcitrant, microbial carbon and nitrogen and the microbial community composition at two Abies faxoniana forest elevations under elevated temperatures
Labile, recalcitrant, microbial carbon and nitrogen and the microbial community composition at two Abies faxoniana forest elevations under elevated temperatures
复制标题
DOI：
10.1016/j.soilbio.2015.08.016
复制
发表时间：
2015-12
影响因子：
9.7
通讯作者：
Gang Xu;Juan Chen;F. Berninger;J. Pumpanen;Jingwen Bai;Lei-Ping Yu;B. Duan
中科院分区：
文献类型：
--
作者：
Gang Xu;Juan Chen;F. Berninger;J. Pumpanen;Jingwen Bai;Lei-Ping Yu;B. Duan
研究了海拔高度和人工增温对亚高山冷杉林土壤微生物群落结构的影响。在3000 m和3500 m两个海拔高度建立了开顶式气室（OTCs），测定了土壤微生物特征、有机碳（C）和氮（N）。通过磷脂脂肪酸（PLFA）分析定量微生物群落结构。采用两步硫酸水解法对土壤有机质中的活性碳和难降解碳组分进行了定量分析。结果表明，随着海拔升高，土壤中细菌和革兰氏阴性菌PLFA含量增加，真菌PLFA含量和菌/菌比值降低。相比之下，在低海拔的这些参数的变暖的影响是小的。土壤中易分解碳的比例较高，这可能是两个海拔高度土壤微生物群落组成不同的原因。RDA分析结果表明，土壤活性氮库（LP-N）、难溶性氮库（RP-N）、活性碳库（C）以及溶解性有机碳（DOC）和溶解性有机氮（DON）含量与土壤有机质特性（如LP-N、RP-N、DOC和DON）的变化有显著的相关性。研究结果还表明，随着海拔的升高，土壤活性碳和氮库逐渐增加，而氯仿熏蒸法测得的微生物生物量碳则呈下降趋势。变暖只增加了高海拔地区的柠檬酸C库。考虑到柠檬酸碳的平均停留时间较长，土壤有机碳库的规模也大得多，结果表明，在我们的情况下，温度升高会增加较高海拔地区的土壤碳库，至少在实验土壤变暖的早期阶段是这样。气候变暖还可能引起微生物群落组成和酶活性的变化，从而导致高海拔土壤生态系统过程的功能变化。
We investigated the interactions of altitude and artificial warming on the soil microbial community structure in a subalpineAbies faxonianaforest in southwestern China after four years of warming. Open top chambers (OTCs) at two elevations (3000 m and 3500 m) were established, and their soil microbial characteristics, organic carbon (C) and nitrogen (N) were measured. The microbial community structure was quantified by phospholipid fatty acid (PLFA) analysis. A two-step sulfuric acid hydrolysis was used to quantify the labile and recalcitrant C fractions in the soil organic matter. The results showed that bacterial PLFAs and gram-negative bacterial PLFAs increased and the fungal PLFAs and the fungi/bacteria ratio decreased with warming at the high altitude. By contrast, the warming effects on those parameters at low altitude were small. The higher proportion of labile easily decomposable soil C may explain the different responses of the microbial community composition at the two altitudes. An RDA analysis confirmed that the variations in the soil community structure were significantly associated with soil organic matter properties such as the sizes of the soil labile N pool (LP-N), the recalcitrant N pool (RP-N), and the labile C pool as well as dissolved organic C (DOC) and dissolved organic N concentrations (DON). Our results also showed that labile C and N pools increased with the altitude, but the microbial biomass C as measured with chloroform fumigation techniques decreased. Warming increased only the recalcitrant C pools at the high altitude. Given the longer mean residence time for recalcitrant C and the much greater size of this soil organic carbon pool, the results indicated that a rise in temperature in our case increased soil C pools at higher altitudes, at least during the early stages of experimental soil warming. Warming could also cause changes in the composition of the microbial community and enzyme activities, consequently leading to functional changes in soil ecosystem processes at the high altitude.