We evaluated how eutrophication and humification impacted nutrient cycles and the efficiency of carbon transfer in the planktonic food webs of 12 lakes in north-eastern Poland that differed in trophic state. Our results indicated that the effectiveness of carbon transfer between phytoplankton and zooplankton varied from 0.0005% to 0.14%, which is much lower than the theoretical 10%. The highest efficiency of carbon transfer occurred in the mesotrophic lakes due to the higher hypolimnetic zooplankton production, while the lowest efficiency was observed in the dystrophic lakes and in one eutrophic lake that was dominated by cyanobacteria. Inedible algae (e.g. Gonyostomum semen ) and cyanobacteria appeared to be the main factors reducing the efficiency of the transfer of matter in pelagic food webs. The results of our study showed that plankton communities are a key component of the nutrient cycle in freshwater food webs. Phytoplankton were a very effective nitrogen sink, and in the mesotrophic lakes, up to 99% of the total nitrogen was sequestrated in phytoplankton. As a result, there was a depletion of inorganic nitrogen in the upper water layer. Furthermore, zooplankton were an important phosphorus sink, thus significantly influencing the nutrient cycles.

中文翻译：

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富营养化和腐殖化对淡水食物网中营养循环和物质转移效率的影响

我们评估了富营养化和腐殖化如何影响营养状态不同的波兰东北部 12 个湖泊的浮游食物网中的营养循环和碳转移效率。我们的研究结果表明，浮游植物和浮游动物之间的碳转移效率从 0.0005% 到 0.14% 不等，远低于理论值的 10%。碳转移效率最高的发生在中营养型湖泊，因为下水层浮游动物产量较高，而在营养不良型湖泊和一个以蓝藻为主的富营养化湖泊中观察到的碳转移效率最低。不可食用的藻类（例如 Gonyostomum semen）和蓝藻似乎是降低远洋食物网中物质转移效率的主要因素。我们的研究结果表明，浮游生物群落是淡水食物网营养循环的关键组成部分。浮游植物是一种非常有效的氮汇，在中营养湖泊中，高达 99% 的总氮被浮游植物吸收。结果，上层水层中的无机氮耗尽。此外，浮游动物是重要的磷汇，从而显着影响营养循环。