University of Washington, School of Oceanography and Astrobiology Program, Seattle, WA, USA.
ISME J. 2012 Jan;6(1):11-20. doi: 10.1038/ismej.2011.76. Epub 2011 Jun 30.
Dramatic decreases in the extent of Arctic multiyear ice (MYI) suggest this environment may disappear as early as 2100, replaced by ecologically different first-year ice. To better understand the implications of this loss on microbial biodiversity, we undertook a detailed census of the microbial community in MYI at two sites near the geographic North Pole using parallel tag sequencing of the 16S rRNA gene. Although the composition of the MYI microbial community has been characterized by previous studies, microbial community structure has not been. Although richness was lower in MYI than in underlying surface water, we found diversity to be comparable using the Simpson and Shannon's indices (for Simpson t=0.65, P=0.56; for Shannon t=0.25, P=0.84 for a Student's t-test of mean values). Cyanobacteria, comprising 6.8% of reads obtained from MYI, were observed for the first time in Arctic sea ice. In addition, several low-abundance clades not previously reported in sea ice were present, including the phylum TM7 and the classes Spartobacteria and Opitutae. Members of Coraliomargarita, a recently described genus of the class Opitutae, were present in sufficient numbers to suggest niche occupation within MYI.
北极多年冰（MYI）范围的急剧减少表明，这种环境可能早在 2100 年就会消失，取而代之的是生态上截然不同的一年生冰。为了更好地了解这种损失对微生物生物多样性的影响，我们使用 16S rRNA 基因的平行标签测序，对北极附近两个地点的 MYI 中的微生物群落进行了详细的普查。虽然之前的研究已经描述了 MYI 微生物群落的组成，但尚未描述其群落结构。尽管 MYI 中的丰富度低于底层地表水，但我们发现使用 Simpson 和 Shannon 指数，多样性是可比的（对于 Simpson t=0.65，P=0.56；对于 Shannon t=0.25，P=0.84，学生 t 检验平均值）。蓝细菌占从 MYI 获得的读数的 6.8%，这是首次在北极海冰中观察到。此外，还存在一些以前未在海冰中报道过的低丰度类群，包括门 TM7 和类 Spartobacteria 和 Opitutae。最近描述的 Opitutae 类的 Coraliomargarita 属的成员数量充足，表明它们在 MYI 中占据了特定的生态位。
