The importance of bacterivorous protists in the decomposition of stream leaf litter
The importance of bacterivorous protists in the decomposition of stream leaf litter
复制标题
食菌原生生物在溪流落叶分解中的重要性
DOI：
10.1111/j.1365-2427.2005.01338.x
复制
发表时间：
2005
影响因子：
2.7
通讯作者：
D. W. Coats
中科院分区：
文献类型：
--
作者：
S. Ribblett;M. Palmer;D. W. Coats
1.异地有机质，以衰老的叶子的形式，是支持碎屑食物网的主要碳来源。虽然研究记录了细菌和真菌在落叶分解过程中的作用，但关于原生生物在分解过程中的作用的信息很少。2.我们验证了这样一个假说，即溪流栖息的食菌原生动物的存在通过对细菌的放牧压力导致叶片分解速度的增加。我们从美国弗吉尼亚州北部(鹅溪)的一条溪流中采集的腐烂树叶中分离出活的原生动物，并建立了常见的食菌原生动物的实验室培养。3.通过室内微宇宙试验，研究了细菌、细菌+鞭毛虫、细菌+鞭毛虫+纤毛虫、高压灭菌溪水4种处理对枯枝落叶分解速率的影响。分别在第0、7、14、30、60和120天测定各重复的叶片干重、细菌丰度、鞭毛虫丰度和纤毛虫丰度。4.原生生物处理的叶片腐解率显著高于不加原生生物的处理，细菌丰度显著低于不加细菌的处理。与单独使用细菌的处理相比，在有原生生物存在的情况下，鞭毛虫存在时的体重损失是单独使用细菌处理的三到四倍。这些结果提供了实验证据，证明原生生物可以在河流的碎屑过程中发挥重要作用。
1. Allochthonous organic matter, in the form of senesced leaves, is a major source of carbon supporting detrital food webs. While studies have documented the role of bacteria and fungi in the decomposition of leaf litter, little information is available regarding the role of protists in the decomposition process. 2. We tested the hypothesis that the presence of stream-dwelling bacterivorous protists leads to an increased rate of leaf decomposition through grazing pressure on bacteria. We isolated live protists from decomposing leaves collected in a stream in Northern Virginia, U.S.A. (Goose Creek) and established laboratory cultures of common bacterivorous protists. 3. Recently senesced leaves from the field were used in laboratory microcosm experiments to determine if the rate of litter decomposition differed between four treatments: bacteria only, bacteria + flagellates, bacteria + flagellates + ciliates, autoclaved stream water (control). We determined the dry weight of leaf remaining, bacterial abundance, flagellate abundance and ciliate abundance for each replicate on days 0, 7, 14, 30, 60 and 120. 4. The rate of leaf decomposition was significantly higher in treatments with protists than without and bacterial abundance declined in protist treatments compared with bacteria only treatment. Weight loss in the presence of flagellates was three to four times higher when protists were present compared with treatments with bacteria alone. These results provide experimental evidence that protists could play a significant role in the detrital processes of streams.