Roth Rosenberg Dalit, Haber Markus, Goldford Joshua, Lalzar Maya, Aharonovich Dikla, Al-Ashhab Ashraf, Lehahn Yoav, Segrè Daniel, Steindler Laura, Sher Daniel
Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel.
Bioinformatics Program, Boston University, Boston, MA, USA.
Environ Microbiol. 2021 Aug;23(8):4295-4308. doi: 10.1111/1462-2920.15611. Epub 2021 Jun 10.
In the oceans and seas, environmental conditions change over multiple temporal and spatial scales. Here, we ask what factors affect the bacterial community structure across time, depth and size fraction during six seasonal cruises (2 years) in the ultra-oligotrophic Eastern Mediterranean Sea. The bacterial community varied most between size fractions (free-living (FL) vs. particle-associated), followed by depth and finally season. The FL community was taxonomically richer and more stable than the particle-associated (PA) one, which was characterized by recurrent 'blooms' of heterotrophic bacteria such as Alteromonas and Ralstonia. The heterotrophic FL and PA communities were also correlated with different environmental parameters: the FL population correlated with depth and phytoplankton, whereas PA bacteria were correlated primarily with the time of sampling. A significant part of the variability in community structure could, however, not be explained by the measured parameters. The metabolic potential of the PA community, predicted from 16S rRNA amplicon data using PICRUSt, was enriched in pathways associated with the degradation and utilization of biological macromolecules, as well as plastics, other petroleum products and herbicides. The FL community was enriched in predicted pathways for the metabolism of inositol phosphate, a potential phosphorus source, and of polycyclic aromatic hydrocarbons.
在海洋中，环境条件会在多个时间和空间尺度上发生变化。在此，我们探讨在超贫营养的东地中海进行的六个季节航次（历时两年）期间，哪些因素会影响不同时间、深度和粒径级分的细菌群落结构。细菌群落结构在粒径级分（自由生活型（FL）与颗粒附着型）之间变化最大，其次是深度，最后是季节。自由生活型群落比颗粒附着型（PA）群落在分类学上更丰富、更稳定，颗粒附着型群落的特征是异养细菌（如交替单胞菌属和罗尔斯通氏菌属）反复出现“水华”现象。自由生活型和颗粒附着型的异养群落也与不同的环境参数相关：自由生活型菌群与深度和浮游植物相关，而颗粒附着型细菌主要与采样时间相关。然而，群落结构中很大一部分变异性无法用所测量的参数来解释。利用PICRUSt从16S rRNA扩增子数据预测的颗粒附着型群落的代谢潜力，在与生物大分子以及塑料、其他石油产品和除草剂的降解与利用相关的途径中得到富集。自由生活型群落则在潜在磷源肌醇磷酸和多环芳烃代谢的预测途径中得到富集。
