Riquelme Cristina, Rigal François, Hathaway Jennifer J M, Northup Diana E, Spilde Michael N, Borges Paulo A V, Gabriel Rosalina, Amorim Isabel R, Dapkevicius Maria de Lurdes N E
Food Science and Health Group (CITA-A), Universidade dos Açores, Departamento de Ciências Agrárias, Rua Capitão João d'Ávila, São Pedro, 9700-042 Angra do Heroísmo, Terceira, Azores, Portugal.
cE3c - Centre for Ecology, Evolution and Environmental Changes/Azorean Biodiversity Group and Universidade dos Açores - Departamento de Ciências Agrárias, Rua Capitão João d'Ávila, São Pedro, 9700-042 Angra do Heroísmo, Terceira, Azores, Portugal Environment and Microbiology Team, MELODY group, Université of Pau et des Pays de l'Adour, IPREM UMR CNRS 5254, BP 1155, 64013 Pau Cedex, France.
FEMS Microbiol Ecol. 2015 Dec;91(12). doi: 10.1093/femsec/fiv141. Epub 2015 Nov 11.
Processes determining diversity and composition of bacterial communities in island volcanic caves are still poorly understood. Here, we characterized colored microbial mats in 14 volcanic caves from two oceanic islands of the Azores using 16S rRNA gene sequences. Factors determining community diversity (α) and composition (β) were explored, namely colored mats, caves and islands, as well as environmental and chemical characteristics of caves. Additive partitioning of diversity using OTU occurrence showed a greater influence of β-diversity between islands and caves that may relate to differences in rare OTUs (singletons and doubletons) across scales. In contrast, Shannon diversity partitioning revealed the importance of the lowest hierarchical level (α diversity, colored mat), suggesting a dominance of cosmopolitan OTUs (>1%) in most samples. Cosmopolitan OTUs included members involved in nitrogen cycling, supporting the importance of this process in Azorean caves. Environmental and chemical conditions in caves did not show any significant relationship to OTU diversity and composition. The absence of clear differences between mat colors and across scales may be explained by (1) the geological youth of the cave system (cave communities have not had enough time to diverge) or/and (2) community convergence, as the result of selection pressure in extreme environments.
决定岛屿火山洞穴中细菌群落多样性和组成的过程仍知之甚少。在此，我们利用16S rRNA基因序列对亚速尔群岛两个大洋岛屿上14个火山洞穴中的有色微生物垫进行了表征。我们探究了决定群落多样性（α）和组成（β）的因素，即有色微生物垫、洞穴和岛屿，以及洞穴的环境和化学特征。使用OTU出现情况进行的多样性加性划分表明，岛屿和洞穴之间的β多样性影响更大，这可能与不同尺度上稀有OTU（单例和双例）的差异有关。相比之下，香农多样性划分揭示了最低层次水平（α多样性，有色微生物垫）的重要性，表明在大多数样本中，世界性OTU（>1%）占主导地位。世界性OTU包括参与氮循环的成员，这支持了该过程在亚速尔群岛洞穴中的重要性。洞穴中的环境和化学条件与OTU多样性和组成没有任何显著关系。垫子颜色之间以及不同尺度上没有明显差异，这可能是由于（1）洞穴系统地质年代较新（洞穴群落没有足够时间分化）或/和（2）群落趋同，这是极端环境中选择压力的结果。
