Free viruses are the most abundant type of biological particles in the biosphere, but the lack of quantitative knowledge about their consumption by heterotrophic protists and bacterial degradation has hindered the inclusion of virovory in biogeochemical models. Using isotope-labeled viruses added to three independent microcosm experiments with natural microbial communities followed by isotope measurements with single-cell resolution and flow cytometry, we quantified the flux of viral C and N into virovorous protists and bacteria and compared the loss of viruses due to abiotic vs biotic factors. We found that some protists can obtain most of their C and N requirements from viral particles and that viral C and N get incorporated into bacterial biomass. We found that bacteria and protists were responsible for increasing the daily removal rate of viruses by 33% to 85%, respectively, compared to abiotic processes alone. Our laboratory incubation experiments showed that abiotic processes removed roughly 50% of the viruses within a week, and adding biotic processes led to a removal of 83% to 91%. Our data provide direct evidence for the transfer of viral C and N back into the microbial loop through protist grazing and bacterial breakdown, representing a globally significant flux that needs to be investigated further to better understand and predictably model the C and N cycles of the hydrosphere.

中文翻译：

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沿海细菌和原生生物吸收病毒的碳和氮


游离病毒是生物圈中最丰富的生物颗粒类型，但缺乏关于异养原生生物消耗和细菌降解的定量知识，阻碍了将病毒纳入生物地球化学模型。使用添加到具有天然微生物群落的三个独立微观实验中的同位素标记病毒，然后用单细胞分辨率和流式细胞术进行同位素测量，我们量化了病毒 C 和 N 进入病毒原生生物和细菌的通量，并比较了由于非生物与生物因素引起的病毒损失。我们发现一些原生生物可以从病毒颗粒中获得大部分 C 和 N 需求，并且病毒 C 和 N 被整合到细菌生物量中。我们发现，与单独的非生物过程相比，细菌和原生生物分别负责将病毒的每日清除率提高 33% 至 85%。我们的实验室孵化实验表明，非生物过程在一周内去除了大约 50% 的病毒，而添加生物过程导致去除了 83% 到 91% 的病毒。我们的数据为病毒 C 和 N 通过原生生物放牧和细菌分解转移回微生物回路提供了直接证据，代表了一个全球显着的通量，需要进一步研究，以更好地理解和预测水圈的 C 和 N 循环。