Abstract

We assessed the efficiency of the transfer of essential substances (carbon, phosphorus, nitrogen, and fatty acids (FA), including polyunsaturated fatty acids (PUFAs)) from phytoplankton to planktonic crustaceans in experimental mesocosms in the presence and absence of fish. The experiments were conducted under mesotrophic conditions in 300 L mesocosms. We have found that transfer efficiencies from producers to consumers are different for different substances. In particular, FA, including PUFAs, are transferred less efficiently than carbon. In contrast, the efficiency of nutrient transfer, especially phosphorus, is higher than that of carbon. This evidences that zooplankton can accumulate nutrients, increasing their quality as a resource for higher trophic levels. Fish significantly reduced the efficiency of carbon transfer from phytoplankton to zooplankton per unit of water volume, but did not affect the transfer of substances per unit of biomass. Thus, the quality of zooplankton as a food resource for higher trophic levels did not decrease in the presence of fish, despite the decline in the efficiency of the transfer of the essential substances per unit of water volume under their influence. Since the efficiency of essential substances transfered from phytoplankton to zooplankton determines the functioning of the entire trophic web, we should seek ways to increase it.

中文翻译：

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中营养条件下浮游植物向浮游甲壳类动物中基本物质转移的效率

摘要

我们评估了在有鱼和无鱼的情况下，实验性中观皮层中必需物质（碳，磷，氮和脂肪酸（FA），包括多不饱和脂肪酸（PUFA））从浮游植物向浮游甲壳类动物转移的效率。实验在中营养条件下在300 L的中等规模环境中进行。我们发现，对于不同的物质，从​​生产者到消费者的转移效率是不同的。特别是，包括PUFA在内的FA的转移效率不及碳。相反，养分转移的效率，尤其是磷，要比碳高。这表明浮游动物可以积累营养，从而提高营养水平，成为更高营养水平的一种资源。鱼类显着降低了每单位水量碳从浮游植物到浮游动物的碳转移效率，但不影响每单位生物量物质的转移。因此，尽管存在鱼类，浮游动物作为营养水平较高的食物资源的质量在鱼类存在的情况下并没有降低，尽管在它们的影响下每单位水量的基本物质的转移效率有所下降。由于从浮游植物转移到浮游动物的基本物质的效率决定了整个营养网的功能，因此我们应该寻求增加营养网的方法。尽管在其影响下每单位水量的基本物质转移效率有所下降。由于从浮游植物转移到浮游动物的基本物质的效率决定了整个营养网的功能，因此我们应该寻求增加营养网的方法。尽管在其影响下每单位水量的基本物质转移效率有所下降。由于从浮游植物转移到浮游动物的基本物质的效率决定了整个营养网的功能，因此我们应该寻求增加营养网的方法。