Trophic Usability, Not Carbon Supply, Constrains Energy Transfer in Eutrophic Food Webs

IF 2.6 2区生物学 Q2 ECOLOGY

Freshwater Biology Pub Date : 2026-10-12 DOI:10.1111/fwb.70320

Hua Song, Fen Guo, David Dudgeon, Hui Jin, Zhenmin Yang, Feilong Li, Yuan Zhang

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引用次数: 0

Abstract

Trophic transfer efficiency (TTE) is commonly quantified from carbon fluxes, implicitly assuming that primary production is uniformly available to consumers. This assumption fails in many eutrophic lakes, where high phytoplankton biomass and carbon production coexist with weak secondary production, a paradox that carbon-centred frameworks have recognized but not mechanistically resolved.
Here, we propose that this mismatch may arise because trophic transfer is constrained not simply by production quantity, but by trophic usability. We applied a dual-currency framework to examine phytoplankton-to-zooplankton transfer in more and less eutrophic regions of two subtropical lakes. Transfer was quantified using bulk carbon and ω3 long-chain polyunsaturated fatty acids (ω3 LC-PUFA), together with information on plankton community composition and inferred trophic-network structure.
Our results show that the more eutrophic regions had higher phytoplankton carbon production and stronger cyanobacterial dominance, whereas the less eutrophic regions had higher phytoplankton ω3 LC-PUFA production and greater contributions of diatoms and cryptophytes. These contrasts coincided with higher zooplankton carbon and ω3 LC-PUFA production and higher TTE in the less eutrophic regions.
ω3 LC-PUFA-based TTE was generally higher than carbon-based TTE, although the difference was not statistically significant in every regional comparison. This metric is therefore best interpreted as a quality-weighted transfer and retention measure reflecting both trophic routing and selective biochemical conservation. Exploratory networks based on observed taxa contained more inferred links in the less eutrophic regions, consistent with regional differences in plankton community structure.
These findings support the view that trophic transfer in eutrophic lakes is associated with the quantity and biochemical quality of primary production, plankton community composition, and selective retention of essential molecules. Although based on a two-lake, single-season correlative comparison, the dual-currency framework provides a complementary approach for evaluating how eutrophication-related changes in basal resources are linked to consumer production and trophic transfer.

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营养可用性，而不是碳供应，限制了富营养化食物网的能量转移

营养转移效率（TTE）通常是通过碳通量来量化的，隐含地假设初级产品对消费者是统一的。这一假设在许多富营养化湖泊中是不成立的，在这些湖泊中，浮游植物生物量和碳产量较高，而次生产量较弱，这是一个以碳为中心的框架已经认识到但尚未从机制上解决的悖论。在这里，我们提出这种不匹配可能是因为营养转移不仅受到产量的限制，而且受到营养可用性的限制。我们应用双货币框架研究了两个亚热带湖泊富营养化程度较高和较低的区域浮游植物向浮游动物的转移。采用体积碳和ω3长链多不饱和脂肪酸（ω3 LC-PUFA）定量转移，并结合浮游生物群落组成信息和推断的营养网络结构。结果表明，富营养化程度越高的区域浮游植物产碳量越大，蓝藻优势越强，而富营养化程度越低的区域浮游植物ω3 LC-PUFA产量越高，硅藻和隐生植物贡献越大。这些对比与富营养化程度较低地区浮游动物碳和ω3 LC-PUFA产量较高以及TTE较高相吻合。ω3 lc - pufa基TTE普遍高于碳基TTE，但各区域比较差异无统计学意义。因此，该指标最好被解释为反映营养路径和选择性生化保护的质量加权转移和保留措施。在富营养化程度较低的地区，基于观察到的分类群的探索网络包含更多的推断联系，这与浮游生物群落结构的区域差异一致。这些发现支持了富营养化湖泊的营养转移与初级生产的数量和生化质量、浮游生物群落组成和必需分子的选择性保留有关的观点。虽然基于两湖、单季节的相关比较，但双货币框架为评估基础资源中与富营养化相关的变化如何与消费者生产和营养转移联系起来提供了一种补充方法。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Freshwater Biology 生物-海洋与淡水生物学

CiteScore

5.90

自引率

3.70%

发文量

162

审稿时长

2 months

期刊介绍： Freshwater Biology publishes papers on all aspects of the ecology of inland waters, including rivers and lakes, ground waters, flood plains and other freshwater wetlands. We include studies of micro-organisms, algae, macrophytes, invertebrates, fish and other vertebrates, as well as those concerning whole systems and related physical and chemical aspects of the environment, provided that they have clear biological relevance. Studies may focus at any level in the ecological hierarchy from physiological ecology and animal behaviour, through population dynamics and evolutionary genetics, to community interactions, biogeography and ecosystem functioning. They may also be at any scale: from microhabitat to landscape, and continental to global. Preference is given to research, whether meta-analytical, experimental, theoretical or descriptive, highlighting causal (ecological) mechanisms from which clearly stated hypotheses are derived. Manuscripts with an experimental or conceptual flavour are particularly welcome, as are those or which integrate laboratory and field work, and studies from less well researched areas of the world. Priority is given to submissions that are likely to interest a wide range of readers. We encourage submission of papers well grounded in ecological theory that deal with issues related to the conservation and management of inland waters. Papers interpreting fundamental research in a way that makes clear its applied, strategic or socio-economic relevance are also welcome. Review articles (FRESHWATER BIOLOGY REVIEWS) and discussion papers (OPINION) are also invited: these enable authors to publish high-quality material outside the constraints of standard research papers.