Zhao Li, Brugel Sonia, Ramasamy Kesava Priyan, Andersson Agneta
Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden.
Umeå Marine Sciences Centre, Umeå University, Hörnefors, Sweden.
Front Microbiol. 2022 Feb 16;12:726844. doi: 10.3389/fmicb.2021.726844. eCollection 2021.
Global warming scenarios indicate that in subarctic regions, the precipitation will increase in the future. Coastal bacteria will thus receive increasing organic carbon sources from land runoff. How such changes will affect the function and taxonomic composition of coastal bacteria is poorly known. We performed a 10-day experiment with two isolated bacteria: from a seaside location and sp. from a river mouth, and provided them with a plankton and a river extract as food substrate. The bacterial growth and carbon consumption were monitored over the experimental period. and consumed 40% and 30% of the plankton extract, respectively, while the consumption of the river extract was low for both bacteria, ∼1%. showed the highest bacterial growth efficiency (BGE) (12%) when grown on plankton extract, while when grown on river extract, the BGE was only 1%. showed low BGE when grown on plankton extract (< 1%) and slightly higher BGE when grown on river extract (2%). The cell growth yield of was higher than that of when grown on river extract. These results indicate that is more adapted to terrestrial organic substrates with low nutritional availability, while is adapted to eutrophied conditions. The different growth performance of the bacteria could be traced to genomic variations. A closely related genome of was shown to harbor genes for the sequestration of autochthonously produced carbon substrates, while contained genes for the degradation of relatively refractive terrestrial organic matter. The results may reflect the influence of environmental drivers on bacterial community composition in natural aquatic environments. Elevated inflows of terrestrial organic matter to coastal areas in subarctic regions would lead to increased occurrence of bacteria adapted to the degradation of complex terrestrial compounds with a low bioavailability.
全球变暖情景表明，在亚北极地区，未来降水量将会增加。沿海细菌因此将从陆地径流中获得越来越多的有机碳源。然而，这种变化将如何影响沿海细菌的功能和分类组成却鲜为人知。我们用两种分离出的细菌进行了为期10天的实验：一种来自海边地点，另一种来自河口，我们为它们提供浮游生物和河水提取物作为食物底物。在实验期间监测细菌的生长和碳消耗情况。第一种细菌和第二种细菌分别消耗了浮游生物提取物的40%和30%，而两种细菌对河水提取物的消耗量都很低，约为1%。第一种细菌在以浮游生物提取物为食时表现出最高的细菌生长效率（BGE）（12%），而在以河水提取物为食时，BGE仅为1%。第二种细菌在以浮游生物提取物为食时表现出较低的BGE（<1%），而在以河水提取物为食时BGE略高（2%）。当以河水提取物为食时，第一种细菌的细胞生长产量高于第二种细菌。这些结果表明，第一种细菌更适应营养可用性低的陆地有机底物，而第二种细菌则适应富营养化条件。细菌不同的生长表现可追溯到基因组变异。与第一种细菌密切相关的基因组显示含有用于封存本地产生的碳底物的基因，而第二种细菌含有用于降解相对难分解的陆地有机物质的基因。这些结果可能反映了环境驱动因素对天然水生环境中细菌群落组成的影响。亚北极地区沿海地区陆地有机物质流入量增加将导致适应降解生物可用性低的复杂陆地化合物的细菌出现频率增加。
