Weitz Joshua S, Stock Charles A, Wilhelm Steven W, Bourouiba Lydia, Coleman Maureen L, Buchan Alison, Follows Michael J, Fuhrman Jed A, Jover Luis F, Lennon Jay T, Middelboe Mathias, Sonderegger Derek L, Suttle Curtis A, Taylor Bradford P, Frede Thingstad T, Wilson William H, Eric Wommack K
1] School of Biology, Georgia Institute of Technology, Atlanta, GA, USA [2] School of Physics, Georgia Institute of Technology, Atlanta, GA, USA.
Geophysical Fluid Dynamics Laboratory, NOAA, Princeton, NJ, USA.
ISME J. 2015 Jun;9(6):1352-64. doi: 10.1038/ismej.2014.220. Epub 2015 Jan 30.
Viral lysis of microbial hosts releases organic matter that can then be assimilated by nontargeted microorganisms. Quantitative estimates of virus-mediated recycling of carbon in marine waters, first established in the late 1990s, were originally extrapolated from marine host and virus densities, host carbon content and inferred viral lysis rates. Yet, these estimates did not explicitly incorporate the cascade of complex feedbacks associated with virus-mediated lysis. To evaluate the role of viruses in shaping community structure and ecosystem functioning, we extend dynamic multitrophic ecosystem models to include a virus component, specifically parameterized for processes taking place in the ocean euphotic zone. Crucially, we are able to solve this model analytically, facilitating evaluation of model behavior under many alternative parameterizations. Analyses reveal that the addition of a virus component promotes the emergence of complex communities. In addition, biomass partitioning of the emergent multitrophic community is consistent with well-established empirical norms in the surface oceans. At steady state, ecosystem fluxes can be probed to characterize the effects that viruses have when compared with putative marine surface ecosystems without viruses. The model suggests that ecosystems with viruses will have (1) increased organic matter recycling, (2) reduced transfer to higher trophic levels and (3) increased net primary productivity. These model findings support hypotheses that viruses can have significant stimulatory effects across whole-ecosystem scales. We suggest that existing efforts to predict carbon and nutrient cycling without considering virus effects are likely to miss essential features of marine food webs that regulate global biogeochemical cycles.
微生物宿主的病毒裂解会释放出有机物质，这些有机物质随后可被非靶向微生物吸收。20世纪90年代末首次建立的海水中病毒介导的碳循环定量估计，最初是根据海洋宿主和病毒密度、宿主碳含量以及推断的病毒裂解率推断出来的。然而，这些估计并没有明确纳入与病毒介导的裂解相关的一系列复杂反馈。为了评估病毒在塑造群落结构和生态系统功能中的作用，我们扩展了动态多营养生态系统模型，以纳入病毒成分，并针对海洋真光层中发生的过程进行了具体参数化。至关重要的是，我们能够通过解析求解这个模型，便于评估在许多替代参数化下的模型行为。分析表明，添加病毒成分促进了复杂群落的出现。此外，新兴多营养群落的生物量分配与表层海洋中已确立的经验规范一致。在稳态下，可以探究生态系统通量，以表征与假定的无病毒海洋表层生态系统相比病毒所产生的影响。该模型表明，有病毒的生态系统将具有：（1）增加的有机物质循环；（2）减少向更高营养级的转移；（三）提高净初级生产力。这些模型结果支持了病毒可以在整个生态系统尺度上产生显著刺激作用的假设。我们认为，现有的在不考虑病毒影响的情况下预测碳和养分循环的努力，很可能会忽略调节全球生物地球化学循环的海洋食物网的基本特征。
