Qian Zhenglu, Zhu Feng, Tan Xiang, Zhang Quanfa
Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, P. R. China.
University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
ISME Commun. 2025 Mar 23;5(1):ycaf051. doi: 10.1093/ismeco/ycaf051. eCollection 2025 Jan.
Periphyton, which is rich in polyunsaturated fatty acids (PUFA), serves as an indispensable high-quality basal resource for consumers in stream food webs. However, with global warming, how fatty acid composition of periphyton changes and consequent effects on their transfer to higher trophic level consumers remain unclear. By carrying out a manipulative mesocosm experiment with a 4°C increase, warming led to a significant decrease in the proportions of PUFA and Long-chain PUFA (LC-PUFA, >20 C) in periphyton from 13.32% to 9.90% and from 3.05% to 2.18%, respectively. The proportions of three PUFAs-α-linolenic acid (18:3ω3), arachidonic acid (ARA, 20:4ω6), and docosahexaenoic acid (22:6ω3)-also declined significantly ( < .05). Notably, the fatty acid profile of the consumer- reflected the changes in basal resources, with a decrease in PUFA from 40.14% to 36.27%, and a significant decrease in LC-PUFA from 34.58% to 30.11%. Although algal community composition in biofilms did not significantly change with warming, significant transcriptomic alterations were observed, with most differentially expressed genes related to fatty acid synthesis in lipid metabolism and photosynthesis down-regulated. Our findings indicate that warming may hinder the production and transfer of high-quality carbon evaluated by LC-PUFA to consumers, consequently affect the complexity and stability of stream food webs.
附着生物富含多不饱和脂肪酸（PUFA），是河流食物网中消费者不可或缺的优质基础资源。然而，随着全球变暖，附着生物的脂肪酸组成如何变化以及对其向更高营养级消费者转移的后续影响仍不清楚。通过进行一项温度升高4°C的控制中宇宙实验，变暖导致附着生物中PUFA和长链PUFA（LC-PUFA，>20个碳）的比例分别从13.32%显著下降到9.90%，从3.05%下降到2.18%。三种PUFA——α-亚麻酸（18:3ω3）、花生四烯酸（ARA，20:4ω6）和二十二碳六烯酸（22:6ω3）的比例也显著下降（P < 0.05）。值得注意的是，消费者的脂肪酸谱反映了基础资源的变化，PUFA从40.14%下降到36.27%，LC-PUFA从34.58%显著下降到30.11%。尽管生物膜中的藻类群落组成并未随变暖而显著变化，但观察到显著的转录组改变，大多数差异表达基因与脂质代谢和光合作用中脂肪酸合成相关且下调。我们的研究结果表明，变暖可能会阻碍以LC-PUFA评估的优质碳向消费者的产生和转移，从而影响河流食物网 的复杂性和稳定性。
