Top-down control of microbial activity and biomass in an Arctic soil ecosystem
Top-down control of microbial activity and biomass in an Arctic soil ecosystem
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DOI：
10.1111/j.1462-2920.2009.02104.x
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发表时间：
2010-03-01
影响因子：
5.1
通讯作者：
Lipson, David
中科院分区：
文献类型：
--
作者：
Allen, Bethany;Willner, Dana;Lipson, David
在全球范围内，土壤微生物控制着巨大的碳库，众所周知，微生物的生物量和活动都受到自下而上的控制，也就是说，受到营养和能量的限制。然而，有证据表明，原生动物的放牧对生物量施加了自上而下的控制。在这里，我们使用阿拉斯加巴罗(北纬71度，西经157度)附近的一个试验场，在2007年生长季期间研究了噬菌体对土壤微生物的自上而下的控制。土壤测量是从覆盖排水和融化的湖盆内的一系列微地形特征的地点进行的，包括高中心和低中心的冰楔多边形，以估计微生物获得碳和氮的情况。通过现场和实验室实验，我们成功地通过减少噬菌体数量增加了微生物生物量和呼吸作用。在土壤中添加碳和养分对生物量或呼吸作用没有显著影响，这表明缺乏自下而上的控制。此外，我们首次使用茶叶提取物作为土壤中的有效抗噬菌体制剂。我们的结果表明，自上而下的控制，如噬菌体捕食，对于调节北极土壤中的微生物活动至关重要。
P>Globally, soil microbes preside over vast carbon stores, and both microbial biomass and activity are known to be regulated by bottom-up controls, that is, limitation by nutrients and energy. However, there is evidence that grazing by protozoans exerts top-down controls on biomass. Here, we investigate top-down control by phage on soil microbes using an experimental site near Barrow, Alaska (71 degrees N, 157 degrees W) during the 2007 growing season. Soil measurements were taken from sites that covered a range of microtopographical features within a drained and thawed lake basin including high- and low-centred ice-wedge polygons to estimate the availability of carbon and nitrogen for microbes. Using both field and laboratory experiments, we successfully increased both microbial biomass and respiration by decreasing phage populations. The addition of carbon and nutrients to soils had no significant effects on biomass or respiration, indicating a lack of bottom-up controls. Additionally, we present the first use of tea extracts as a potent anti-phage agent in soils. Our results suggest that top-down controls, such as phage predation, are critical to regulation of microbial activities in Arctic soils.