Effects of resources and food web structure on bacterioplankton production in a tropical humic lagoon
Effects of resources and food web structure on bacterioplankton production in a tropical humic lagoon
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资源和食物网结构对热带腐殖质泻湖浮游细菌生产的影响
DOI：
10.1093/plankt/fbr049
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发表时间：
2011
影响因子：
2.1
通讯作者：
V. Farjalla
中科院分区：
文献类型：
--
作者：
E. S. Fonte;L. Carneiro;Adriano Caliman;R. Bozelli;F. Esteves;V. Farjalla
大多数关于浮游细菌过程调节机制的研究都集中在评估营养盐和捕食的孤立效应上。然而，在自然生态系统中，微生物可能与较大的生物体以一系列复杂的、直接的和间接的相互依赖关系强烈地相互作用。在这项工作中，我们报告了一个现场围隔实验的结果，在这个实验中，我们评估了资源可用性（N和P添加）的个体和相互作用的影响，以及来自杂食性鱼类（Hyphessobrycon bifasciatus）对浮游细菌生产（BP）的间接影响。营养物添加和鱼类存在对BP都有个体正效应，但自下而上的控制效应强于间接自上而下的控制效应。营养盐对BP的正效应主要是通过增加无机N和P的有效性而直接产生的，鱼与营养盐之间没有明显的相互作用。杂食性鱼类对BP的正的间接自上而下效应可能与鱼类介导的浮游动物群落结构变化和鱼类介导的跨生境营养更新有关。我们的研究结果表明，食物网结构的变化，由于存在或不存在脊椎动物巨消费者，也可以影响异养微生物的过程。关键词：营养相互作用;无机营养盐;杂食性鱼类;微生物食物网;围隔
The majority of studies of mechanisms regulating bacterioplankton processes havefocused on assessing the isolated effects of nutrients and predation. However, innatural ecosystems, microorganisms may interact strongly with larger organisms inan array of complex, direct and indirect interdependencies. In this work, wereport the results of a field mesocosm experiment in which, over 7 weeks, we eval-uated the individual and interactive effects of resource availability (N and Paddition) and indirect effects originating from the presence of an omnivorous fishspecies (Hyphessobrycon bifasciatus) on bacterioplankton production (BP). Nutrientaddition and fish presence both had individual positive effects on BP, but bottom-up control effects were stronger than indirect top-down control effects. The posi-tive effect of nutrients on BP was mainly direct, through increasing the availabilityof inorganic N and P. There was no significant interaction between fish and nutri-ents. The positive indirect top-down effects of omnivorous fish on BP were prob-ably related to both fish-mediated changes in the zooplankton communitystructure and fish-mediated cross-habitat nutrient regeneration. Our results showthat changes in food web structure, due to the presence or absence of vertebratemacroconsumers, can also affect heterotrophic microbial processes.KEYWORDS: trophic interactions; inorganic nutrients; omnivorous fish;microbial food web; enclosures