Concentration and chemical composition of dissolved organic carbon (DOC) influence several lake functions; greenhouse gas exchange, nutrient cycling, food webs, and water treatability. To assess spatial and inter-annual controls on DOC characteristics, 34 lakes were sampled annually for 8 years on the Boreal Plains, Western Canada—a region with heterogeneous surficial geology, and a sub-humid climate with pronounced inter-annual wet-dry periods. Large spatial variability in long-term average DOC concentration (10–49 mg C L⁻¹) and aromaticity (SUVA₂₅₄: 1.2–3.9 L mg⁻¹ C m⁻¹) among lakes was found. Higher DOC concentrations and aromaticity were associated with lakes in watersheds with fine-textured surficial geology and with relatively large contributions through shallow, organic-rich flow paths. Lake DOC aromaticity was also higher in lakes with lower evaporative enrichment, regardless of surficial geology, indicating shorter lake water residence times and less within-lake degradation of allochthonous DOC. High inter-annual variability for both DOC and aromaticity was observed, with coefficients of variation at 10.9 ± 4.6% and 11.1 ± 2.5% among lakes, respectively. Inter-annual variability in DOC concentrations had low synchronicity among lakes, with patterns of variability linked to surficial geology and primarily responsive to short-term cumulative precipitation. Conversely, inter-annual variability in aromaticity had high synchronicity among lakes, driven by longer-term cumulative precipitation and shifts in lake water residence times. Our study shows it is necessary to consider lake hydrogeomorphic setting and climate to understand spatial and inter-annual variability in lake DOC characteristics and associated lake functions, and that Boreal Plains lakes have high climate sensitivity.

中文翻译：

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北方湖泊溶解有机碳特征：景观属性和干湿期控制的高空间和年际变化

溶解有机碳 (DOC) 的浓度和化学成分会影响湖泊的多种功能；温室气体交换、养分循环、食物网和水处理能力。为了评估对 DOC 特征的空间和年际控制，在 8 年内每年对加拿大西部北部平原的 34 个湖泊进行采样，该地区地表地质异质，半湿润气候，年际干湿期明显. 长期平均 DOC 浓度 (10–49 mg CL ^-1 ) 和芳香性 (SUVA ₂₅₄ : 1.2–3.9 L mg ^-1  C m ^-1 ) 的空间变异性很大) 在湖泊中被发现。较高的 DOC 浓度和芳香性与流域中的湖泊有关，这些湖泊具有精细的地表地质，并且通过浅层、富含有机物的流动路径具有相对较大的贡献。无论地表地质如何，蒸发富集较低的湖泊中，湖泊 DOC 的芳香性也较高，这表明湖水停留时间较短，外来 DOC 的湖内降解较少。观察到 DOC 和芳香性的高年际变异性，湖泊之间的变异系数分别为 10.9 ± 4.6% 和 11.1 ± 2.5%。DOC 浓度的年际变化在湖泊之间具有低同步性，变化模式与地表地质有关，主要对短期累积降水做出反应。反过来，由于长期累积降水和湖水停留时间的变化，芳香性的年际变化在湖泊之间具有高度同步性。我们的研究表明，有必要考虑湖泊水文地貌环境和气候，以了解湖泊 DOC 特征和相关湖泊功能的空间和年际变化，并且北方平原湖泊具有较高的气候敏感性。