Department of Botany, The Natural History Museum, London, UK.
FEMS Microbiol Ecol. 2012 Nov;82(2):356-66. doi: 10.1111/j.1574-6941.2012.01380.x. Epub 2012 Apr 30.
The Pyramid Trough (Lat 78°S) has recently gained protection under the Antarctic Treaty system, owing to its wetland values. Here, we describe the microbial diversity of this system, with emphasis on cyanobacteria, and evaluate environment-biota relationships. Geochemistry separates ponds along hydrological gradients receiving recent inflows of dilute meltwater, from a second group that is rarely inundated and where chemistry is dominated by evaporation. Cyanobacteria-based microbial mats dominated the biota throughout. Mats were characterized by light-microscopy, pigment analysis, automated ribosomal intergenic spacer analysis and 16S rRNA gene clone libraries. A total of 17 morphotypes and 21 ribotypes were identified, mostly Oscillatoriales and several taxa that are usually rare in continental Antarctica, including Chroococcales and scytomin-rich Calothrix/Dichothrix, were abundant. There was a general decline in cyanobacterial diversity with increasing conductivity, but weak support for either differences in community composition between the two groups of ponds or sorting of taxa along the hydrological gradients with the pond groups. This implies a broad environmental tolerance and a prevalence of neutral assembly mechanisms in cyanobacterial communities of Antarctic wetland ecosystems.
金字塔槽（南纬 78°）由于其湿地价值，最近在南极条约体系下受到保护。在这里，我们描述了这个系统的微生物多样性，重点是蓝藻，并评估了环境与生物群的关系。地球化学将沿着接受最近稀释融水流入的水文梯度的池塘与第二组池塘分开，第二组池塘很少被淹没，其化学性质主要由蒸发决定。以蓝藻为基础的微生物垫在整个生物群中占主导地位。通过光学显微镜、色素分析、自动核糖体基因间隔区分析和 16S rRNA 基因克隆文库对垫子进行了表征。总共鉴定出 17 种形态和 21 种核糖体类型，主要是颤藻目和几个通常在南极洲大陆很少见的类群，包括色球藻目和富含 scytomin 的念珠藻/束丝藻，非常丰富。随着电导率的增加，蓝藻的多样性普遍下降，但对两组池塘之间群落组成的差异或沿水文学梯度与池塘群的分类的支持较弱。这意味着在南极湿地生态系统的蓝藻群落中存在广泛的环境耐受性和中性组装机制。
