Sebastián Marta, Giner Caterina R, Balagué Vanessa, Gómez-Letona Markel, Massana Ramon, Logares Ramiro, Duarte Carlos M, Gasol Josep M
Department of Marine Biology and Oceanography, Institut de Ciències del Mar, CSIC. Pg Marítim de la Barceloneta 37-49, Barcelona, Catalunya E08003, Spain.
Instituto de Oceanografía y Cambio Global, Universidad de Las Palmas de Gran Canaria, Parque Científico Tecnológico Marino de Taliarte, s/n, Telde, Las Palmas 35214, Spain.
ISME Commun. 2024 Jan 23;4(1):ycae015. doi: 10.1093/ismeco/ycae015. eCollection 2024 Jan.
A persistent microbial seed bank is postulated to sustain the marine biosphere, and recent findings show that prokaryotic taxa present in the ocean's surface dominate prokaryotic communities throughout the water column. Yet, environmental conditions exert a tight control on the activity of prokaryotes, and drastic changes in these conditions are known to occur from the surface to deep waters. The simultaneous characterization of the total (DNA) and active (i.e. with potential for protein synthesis, RNA) free-living communities in 13 stations distributed across the tropical and subtropical global ocean allowed us to assess their change in structure and diversity along the water column. We observed that active communities were surprisingly more similar along the vertical gradient than total communities. Looking at the vertical connectivity of the active vs. the total communities, we found that taxa detected in the surface sometimes accounted for more than 75% of the active microbiome of bathypelagic waters (50% on average). These active taxa were generally rare in the surface, representing a small fraction of all the surface taxa. Our findings show that the drastic vertical change in environmental conditions leads to the inactivation and disappearance of a large proportion of surface taxa, but some surface-rare taxa remain active (or with potential for protein synthesis) and dominate the bathypelagic active microbiome.
据推测，一个持久的微生物种子库维持着海洋生物圈，最近的研究结果表明，海洋表层存在的原核生物类群主导着整个水柱中的原核生物群落。然而，环境条件对原核生物的活动施加了严格的控制，而且已知从表层到深水这些条件会发生剧烈变化。对分布在热带和亚热带全球海洋的13个站点的总（DNA）和活跃（即具有蛋白质合成潜力的RNA）自由生活群落进行同步表征，使我们能够评估它们在水柱中结构和多样性的变化。我们观察到，活跃群落沿垂直梯度的相似性出人意料地高于总群落。观察活跃群落与总群落的垂直连通性时，我们发现表层检测到的类群有时占深海中层水域活跃微生物组的75%以上（平均为50%）。这些活跃类群在表层通常很稀少，仅占所有表层类群的一小部分。我们的研究结果表明，环境条件的剧烈垂直变化导致很大一部分表层类群失活和消失，但一些在表层稀少的类群仍然活跃（或具有蛋白质合成潜力）并主导着深海中层活跃微生物组。
