Fluxes of root-derived carbon into the nematode micro-food web of an arable soil
Fluxes of root-derived carbon into the nematode micro-food web of an arable soil
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DOI：
10.1016/j.fooweb.2016.05.001
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发表时间：
2016-12
期刊：
影响因子：
1.7
通讯作者：
J. Pausch;S. Hofmann;Anika Scharroba;Y. Kuzyakov;Liliane Ruess
中科院分区：
文献类型：
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作者：
J. Pausch;S. Hofmann;Anika Scharroba;Y. Kuzyakov;Liliane Ruess
从活根释放的有机碳（C）形成微生物控制能量、C途径以及因此控制食物网结构和动力学的主要资源。然而，知识的定量碳通量进入食物网车厢是稀缺的。线虫，在每个营养级的功能组，作为一个模型社区评估根碳通量进入微食物网。用14CO2脉冲标记种植在农田土芯上的玉米，然后在标记后2、5、10和16天取样。通过对线虫种群密度、群落结构、营养类群和14C活性的分析，共检测到线虫22科55属。密度最高的植食植物表现出最快和最高的根C掺入。细菌饲养者比真菌饲养者纳入更多的根衍生14 C。这与0.63的细菌与真菌饲养者比率和中等至低的通道指数（平均38）一致，这是一种线虫动物群指数，用于确定通过细菌或真菌通道的碳流大小，两者都表明细菌分解途径中的主要能量通量。14 C示踪与线虫分类鉴定相结合，可以定量分析根源碳向食物网各分区的迁移。根碳进入线虫的比例很小（约为微生物生物量的0.1%），但由于其连接微生物和动物食物网，因此是地下碳通道的重要组成部分。
Organic carbon (C) released from living roots forms a major resource for microorganisms controlling energy, C pathways and, hence, food web structure and dynamics. However, knowledge on quantitative C fluxes into food web compartments is scarce. Nematodes, with functional groups at each trophic level, served as a model community for assessing root C fluxes into the micro-food web. Maize, grown on soil cores from an arable field, was pulse-labeled with14CO2followed by sampling 2, 5, 10 and 16 days after labeling. Nematode population density, community structure, trophic groups and their14C activities were analyzed.Overall, 55 genera of 22 families were detected. Plant-feeders, which had the highest density, showed the fastest and highest incorporation of root C. Bacterial-feeders incorporated more root-derived14C than fungal-feeders. This was consistent with a bacterial- to fungal-feeder-ratio of 0.63 and a moderate to low Channel Index (average 38), a nematode faunal index that assigns the magnitude of carbon flow via the bacterial or fungal channel, both indicating a major energy flux in the bacterial decomposition pathway. Predators and omnivores showed low incorporation of root-derived C, pointing to a basal food web structure with short food chains and low energy transfer to higher trophic levels.Combining14C tracing with taxonomic identification of nematodes allowed quantification of root C fluxes into food web compartments. The incorporation of root C into nematodes was small (~ 0.1% of that in microbial biomass), yet forms an important part of belowground C channeling as it links microbial and faunal food web.