The spatial and seasonal variations of methane‐derived carbon contributions to Chironomus plumosus larvae and oligochaetes biomass at four stations in a polymictic, eutrophic lake were examined to determine which factors (CH₄ and/or dissolved oxygen) affect the methane‐derived carbon contributions, and quantify impacts of benthic methane‐derived carbon on the lake food web. Methane‐derived carbon contributions were estimated by a two‐source mixing model using δ¹³C values of monthly particulate organic matter ( −29.5 to −20.8‰) and methane‐oxidizing bacteria (−85.7‰). Large spatial and seasonal variability of methane‐derived carbon contributions to C. plumosus and oligochaetes within the lake (0–38% and 0–32%, respectively) were observed, where contributions varied spatially along a gradient of sediment CH₄ concentration, but not dissolved oxygen. The results suggest that for both C. plumosus and oligochaetes, spatial variabilities of the methane‐derived carbon contributions are regulated by CH₄. Seasonal variability of methane‐derived carbon contributions to C. plumosus revealed increases in summer and autumn following increases in CH₄. Methane‐derived biomass (methane‐derived carbon% × biomass) of C. plumosus were also higher in summer and autumn, suggesting transfer of methane‐derived carbon to higher trophic organisms may be larger during those seasons, and limited in winter and spring. Although oligochaetes did not show seasonal variability of methane‐derived carbon contributions, they provided a consistent source of methane‐derived biomass to higher trophic levels throughout the year. Our study demonstrates that two major macroinvertebrates complementarily contribute to fueling methane‐derived carbon cycling through trophic transfer in a polymictic lake.

中文翻译：

---

底栖甲烷源碳在一个多湖泊中随季节，生物和沉积梯度的变化

考察了富营养化湖泊中四个站甲烷源碳对Chi肉幼虫和低毛生物的碳贡献的空间和季节变化，以确定哪些因素（CH ₄和/或溶解氧）影响甲烷源碳的贡献，并量化底栖甲烷源碳对湖泊食物网的影响。甲烷来源的碳的贡献通过使用δ两源混合模型来估计^13倍的每月颗粒有机物（-29.5至-20.8‰）和甲烷氧化菌（-85.7‰）C的值。甲烷衍生的甲烷对碳的贡献的空间和季节变化很大并观察到湖中的低碳藻类（分别为0-38％和0-32％），其贡献沿沉积物CH ₄浓度的梯度在空间上变化，但没有溶解氧。结果表明，对于C. plumosus和oligochaetes，甲烷衍生碳贡献的空间变异性受CH ₄调节。甲烷衍生的碳对甲烷的贡献的季节变化表明，随着CH _4的增加，夏季和秋季都有增加。羽衣梭菌的甲烷衍生生物量（甲烷衍生碳％×生物量）在夏季和秋季也较高，这表明在这些季节中，甲烷衍生的碳向较高营养性生物的转移可能更大，而冬季和春季则有限。尽管低聚类没有显示甲烷衍生的碳贡献的季节性变化，但它们为全年的营养水平提供了一致的甲烷衍生生物量来源。我们的研究表明，两个主要的大型无脊椎动物通过在多学科湖泊中的营养转移，辅助促进了甲烷衍生的碳循环。