How microbial populations interact influences the availability and flux of organic carbon in the ocean. Understanding how these interactions vary over broad spatial scales is therefore a fundamental aim of microbial oceanography. In this study, we assessed variations in the abundances, production, virus and grazing induced mortality of heterotrophic prokaryotes during summer along a meridional gradient in stratification in the North Atlantic Ocean. Heterotrophic prokaryote abundance and activity varied with phytoplankton biomass, while the relative distribution of prokaryotic subpopulations (ratio of high nucleic acid fluorescent (HNA) and low nucleic acid fluorescent (LNA) cells) was significantly correlated to phytoplankton mortality mode (i.e., viral lysis to grazing rate ratio). Virus-mediate morality was the primary loss process regulating the heterotrophic prokaryotic communities (average 55% of the total mortality), which may be attributed to the strong top-down regulation of the bacterivorous protozoans. Host availability, encounter rate, and HNA:LNA were important factors regulating viral dynamics. Conversely, the abundance and activity of bacterivorous protozoans were largely regulated by temperature and turbulence. The ratio of total microbial mediated mortality to total available prokaryote carbon reveals that over the latitudinal gradient the heterotrophic prokaryote community gradually moved from a near steady state system regulated by high turnover in subtropical region to net heterotrophic production in the temperate region.

中文翻译：

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病毒活性对调节东北大西洋沿子午线梯度的异养原核生物群落动力学的意义

微生物种群之间的相互作用方式会影响海洋中有机碳的利用率和通量。因此，了解这些相互作用在广泛的空间尺度上如何变化是微生物海洋学的基本目标。在这项研究中，我们评估了北大西洋沿层状子午线梯度在夏季丰度，产量，病毒和放牧引起的异养原核生物死亡率的变化。异养原核生物的丰度和活性随浮游生物量的变化而变化，而原核亚群的相对分布（高核酸荧光（HNA）和低核酸荧光（LNA）的比例）与浮游植物的死亡率模式（即病毒裂解为放牧率比）。病毒介导的道德是调节异养原核生物群落的主要损失过程（平均占总死亡率的55％），这可能归因于对细菌原生动物的强烈自上而下的调节。宿主可用性，遭遇率和HNA：LNA是调节病毒动力学的重要因素。相反，细菌原生动物的丰度和活性在很大程度上受温度和湍流的调节。总微生物介导的死亡率与总可用原核生物碳的比值表明，在纬度梯度上，异养原核生物群落逐渐从由亚热带地区高周转所调节的近稳态系统转变为温带地区的净异养产量。这可能归因于细菌原生动物的强烈的自上而下的调节。宿主可用性，遭遇率和HNA：LNA是调节病毒动力学的重要因素。相反，细菌原生动物的丰度和活性在很大程度上受温度和湍流的调节。总微生物介导的死亡率与总可用原核生物碳的比值表明，在纬度梯度上，异养原核生物群落逐渐从由亚热带地区高周转所调节的近稳态系统转变为温带地区的净异养产量。这可能归因于细菌原生动物的强烈的自上而下的调节。宿主可用性，遭遇率和HNA：LNA是调节病毒动力学的重要因素。相反，细菌原生动物的丰度和活性在很大程度上受温度和湍流的调节。总微生物介导的死亡率与总可用原核生物碳的比值表明，在纬度梯度上，异养原核生物群落逐渐从由亚热带地区高周转所调节的近稳态系统转变为温带地区的净异养产量。细菌原生动物的丰度和活性在很大程度上受温度和湍流的调节。总微生物介导的死亡率与总可用原核生物碳的比值表明，在纬度梯度上，异养原核生物群落逐渐从由亚热带地区高周转所调节的近稳态系统转变为温带地区的净异养产量。细菌原生动物的丰度和活性在很大程度上受温度和湍流的调节。总微生物介导的死亡率与总可用原核生物碳的比值表明，在纬度梯度上，异养原核生物群落逐渐从由亚热带地区高周转所调节的近稳态系统转变为温带地区的净异养产量。