Submersed macrophytes play a key role in structuring bacterioplankton community composition in the large, shallow, subtropical Taihu Lake, China
Submersed macrophytes play a key role in structuring bacterioplankton community composition in the large, shallow, subtropical Taihu Lake, China
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DOI：
10.1111/j.1462-2920.2007.01388.x
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发表时间：
2007-11-01
影响因子：
5.1
通讯作者：
Hahn, Martin W.
中科院分区：
文献类型：
--
作者：
Wu, Qinglong L.;Zwart, Gabriel;Hahn, Martin W.
在大型浅水亚热带太湖（面积2338平方千米，最大深度<3米）中，对浮游细菌群落组成（BCC）的湖内水平异质性进行了研究。2004年8月和9月，沿着从中营养到富营养区域的营养梯度，在17个位点采集了样本。这些位点涵盖了浅水湖泊的两种交替稳定状态，其基本特征是沉水植物占优势或缺乏沉水植物。就太湖而言，以沉水植物为主的状态具有水体清澈和沉积物稳定的特点，而基本缺乏沉水植物的状态则以浮游植物占优势、频繁的风力驱动的沉积物再悬浮以及高浊度为特征。采用了三种不同的方法，即变性梯度凝胶电泳（DGGE）、针对17个淡水细菌类群的探针进行的反向线杂交（RLB）以及16S rRNA基因克隆和测序，对BCC进行分析。BCC在两种交替的生态状态之间差异很大，但在以浮游植物为主的位点之间差异不太明显，即使叶绿素a浓度梯度从16.5微克/升（中营养）到229.8微克/升（富营养）。代表浑浊水体状态的16S rRNA基因文库包含许多与先前从土壤或淡水沉积物样本中获得的序列密切相关的序列。此外，从所研究的样本中获得了代表两个新的淡水放线菌谱系的序列。对沿所研究的生态梯度的BCC进行的比较统计分析表明，沉水植物的优势是对BCC最具影响力的因素，是太湖中观察到的BCC生境内异质性的主要原因。
Within-lake horizontal heterogeneity of bacterioplankton community composition (BCC) was investigated in the large and shallow subtropical Taihu Lake (2338 km(2), maximum depth < 3 m). Samples were collected at 17 sites along a trophic gradient ranging from mesotrophic to hypertrophic areas in August and September 2004. These sites cover two alternative stable states of shallow lakes, which are basically characterized by the dominance or the lack of submerged macrophytes. In the case of Taihu Lake, the macrophyte-dominated state is characterized by clear water and immobilized sediment, and the state largely lacking macrophytes is characterized by the dominance of phytoplankton, frequent wind-driven re-suspension of sediments, and a high turbidity. Three different methods, i.e. denaturing gradient gel electrophoresis (DGGE), reverse line blot hybridization (RLB) with probes targeting 17 freshwater bacterial groups, and 16S rRNA gene cloning and sequencing, were used for analysis of BCC. The BCC varied strongly between the two alternative ecological states, but less pronounced between phytoplankton-dominated sites even spanning chlorophyll a gradients from 16.5 (mesotrophic) to 229.8 mu g l(-1) (hypertrophic). The 16S rRNA gene library representing the turbid water state contained many sequences closely related to sequences previously obtained from soil or freshwater sediment samples. Furthermore, sequences representing two new lineages of freshwater Actinobacteria were obtained from the investigated samples. Comparative statistical analyses of BCC along the investigated ecological gradients revealed that the dominance of submersed macrophytes was the most influential factor on BCC, responsible for a major part of the observed within-habitat heterogeneity of BCC in Taihu Lake.