Clarke Laurence J, Suter Léonie, King Robert, Bissett Andrew, Deagle Bruce E
Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Hobart, TAS, Australia.
Australian Antarctic Division, Kingston, TAS, Australia.
Front Microbiol. 2019 Jan 15;9:3226. doi: 10.3389/fmicb.2018.03226. eCollection 2018.
Host-associated bacterial communities have received limited attention in polar habitats, but are likely to represent distinct nutrient-rich niches compared to the surrounding environment. Antarctic krill () are a super-abundant species with a circumpolar distribution, and the krill microbiome may make a substantial contribution to marine bacterial diversity in the Southern Ocean. We used high-throughput sequencing of the bacterial 16S ribosomal RNA gene to characterize bacterial diversity in seawater and krill tissue samples from four locations south of the Kerguelen Plateau, one of the most productive regions in the Indian Sector of the Southern Ocean. Krill-associated bacterial communities were distinct from those of the surrounding seawater, with different communities inhabiting the moults, digestive tract and faecal pellets, including several phyla not detected in the surrounding seawater. Digestive tissues from many individuals contained a potential gut symbiont (order: Mycoplasmoidales) shown to improve survival on a low quality diet in other crustaceans. Antarctic krill swarms thus influence Southern Ocean microbial communities not only through top-down grazing of eukaryotic cells and release of nutrients into the water column, but also by transporting distinct microbial assemblages horizontally via migration and vertically via sinking faecal pellets and moulted exuviae. Changes to Antarctic krill demographics or distribution through fishing pressure or climate-induced range shifts will also influence the composition and dispersal of Southern Ocean microbial communities.
与宿主相关的细菌群落在极地栖息地受到的关注有限，但与周围环境相比，它们可能代表着截然不同的营养丰富的生态位。南极磷虾（）是一种分布于环极地的超级丰富物种，磷虾微生物群可能对南大洋的海洋细菌多样性做出重大贡献。我们利用细菌16S核糖体RNA基因的高通量测序来表征来自凯尔盖朗高原以南四个地点（南大洋印度洋区域最具生产力的地区之一）的海水和磷虾组织样本中的细菌多样性。与磷虾相关的细菌群落与周围海水的细菌群落不同，在蜕皮、消化道和粪便颗粒中栖息着不同的群落，包括在周围海水中未检测到的几个门。许多个体的消化组织中含有一种潜在的肠道共生菌（目：支原体目），在其他甲壳类动物中，这种共生菌已被证明能提高在低质量食物上的存活率。因此，南极磷虾群不仅通过自上而下捕食真核细胞并将营养物质释放到水柱中，而且还通过迁移水平运输不同的微生物组合以及通过下沉的粪便颗粒和蜕皮垂直运输不同的微生物组合，从而影响南大洋微生物群落。南极磷虾数量或分布因捕捞压力或气候引起的范围变化而发生的改变，也将影响南大洋微生物群落的组成和扩散。
