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首页> 外文期刊>Turkish Journal of Fisheries & Aquatic Sciences >Quantification of the synergistic effects of eutrophication, apex predator pressure, and internal processes on the Black Sea ecosystem.
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Quantification of the synergistic effects of eutrophication, apex predator pressure, and internal processes on the Black Sea ecosystem.

机译：对黑海生态系统富营养化，尖顶捕食者的压力和内部过程的协同效应进行量化。

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摘要

In the present study, a model of the lower-trophic pelagic food web of the Black Sea is considered in order to provide a quantitative understanding of the marked changes in the food web structure in response to changing top-down and bottom-up control mechanisms due to eutrophication, overfishing, and climatic changes. The simulations consider three particular parameters controlling the changes in the ecosystem structure due to these stressors; (i) the magnitude of the nitrate flux into the euphotic layer from the chemocline layer (enrichment due to eutrophication), (ii) the magnitude of predation control introduced by the planktivorous fish on mesozooplankton (fishery), (iii) the magnitude of the Q10 parameter controlling temperature dependence of the Mnemiopsis growth (changing climatic conditions). A simulation assessing the level of enrichment on the ecosystem indicates a shift of the major trophic energy flow towards Noctiluca and Aurelia and thus showing how the ecosystem would degrade when a critical level of enrichment is passed. Increasing predation pressure of the planktivorous fish during the enrichment phase is shown to reduce the mesozooplankton biomass that in turn declines its predation pressure on Noctiluca population and thus allows Noctiluca biomass to increase, considering that mesozooplanton is assumed to feed on Noctiluca (at a level of 15% food preference) in the current model. Noctiluca then acts as a major consumer and a critical element of the degraded food web structure. The overfishing of planktivorous fish stocks allows Mnemiopsis biomass to increase considerably under changing (warmer) climatic conditions at the end of 1980s, following a decade-long intense cooling phase. Thus, our results suggest that overfishing would not alone be able to promote a Mnemiopsis population outburst in the absence of warming.
机译：在本研究中，考虑使用黑海中低层上层食物网的模型，以定量了解食物网结构响应自上而下和自下而上的控制机制而发生的显着变化由于富营养化，过度捕捞和气候变化。这些模拟考虑了三个特定参数，这些参数控制着这些压力因素导致的生态系统结构的变化。 （i）从趋化层进入富营养层的硝酸盐通量（由于富营养化引起的富集），（ii）浮游鱼类在中型浮游动物（渔业）上引入的捕食控制量，（iii） Q 10 参数控制着拟南芥生长的温度依赖性（气候条件的变化）。评估生态系统富集水平的模拟表明，主要营养能量流向Noctiluca和Aurelia转移，从而显示了通过临界富集水平后生态系统将如何退化。研究表明，在富集阶段，浮游鱼类的捕食压力增加会降低中层浮游生物的生物量，进而降低其对夜光藻种群的捕食压力，从而使夜光藻的生物量增加，考虑到假定中层浮游植物以夜光藻为食（水平为15％的食物偏好）。夜光藻随后成为降解食物网结构的主要消费者和关键元素。在长达十年的强烈冷却阶段之后，1980年代末，浮游性鱼类种群的过度捕捞使Mnemiopsis生物量在变化（较暖）的气候条件下显着增加。因此，我们的结果表明，在没有变暖的情况下，过度捕捞并不能单独促进Mnemiopsis种群的爆发。

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