The oxygen isotope composition (δ¹⁸O) of aquatic cellulose extracted from lake sediment cores has long been used to reconstruct past hydrological responses to climate variation and anthropogenic (e.g. mining, agriculture, forestry) disturbance. Application of this method depends upon a constant oxygen isotope fractionation factor between aquatic cellulose and lake water, often reported as α¹⁸O_cell-lw = 1.028. Prior field-based assessments of α¹⁸O_cell-lw, however, commonly relied on one-time measures of lake water δ¹⁸O, which introduces uncertainties because values may not represent lake water δ¹⁸O at the time of cellulose synthesis. We field-tested the use of α¹⁸O_cell-lw = 1.028 across a broad hydrological gradient of lakes within the Peace-Athabasca Delta (PAD), west-central Canada, where we constrained cellulose production by periphyton on artificial substrates to bracketed measurements of lake water δ¹⁸O collected in late May 2015 and late June 2015. Cellulose-inferred lake water δ¹⁸O, calculated using α¹⁸O_cell-lw of 1.028 ± 0.0015, corresponded with the range of measured lake water δ¹⁸O in 36 of 52 (75%) of our study lakes. Agreement improved to 86% for ‘clean cellulose’ samples that appeared to be of higher quality (i.e. those with minimal minerogenic material). Mean apparent α¹⁸O_cell-lw calculated for clean cellulose samples, using both May lake water δ¹⁸O (1.0286) and the May–June mean lake water δ¹⁸O (1.0275), did not differ significantly from 1.028, but was significantly, albeit slightly, below 1.028 using June lake water δ¹⁸O (1.0264). Closer correspondence of apparent α¹⁸O_cell-lw, calculated using May and May–June average lake water δ¹⁸O, suggested rapid and early colonization and cellulose production by periphyton. For samples that were a mixture of cellulose and minerogenic material, mean apparent α¹⁸O_cell-lw was significantly below 1.028 for these corresponding lake water δ¹⁸O measurements, but differences were small and would potentially lead to under-estimation of cellulose-inferred lake water δ¹⁸O by only 1–2‰ in sediment stratigraphic records. Overall, strong agreement observed between the cellulose-inferred and directly measured lake water δ¹⁸O supports application of α¹⁸O_cell-lw = 1.028 ± 0.0015 and lends confidence to paleohydrological reconstructions using this method in lakes of the PAD and elsewhere.

从湖泊沉积物核心中提取的水生纤维素的氧同位素组成 (δ ¹⁸ O) 长期以来一直被用于重建过去对气候变化和人为（例如采矿、农业、林业）干扰的水文响应。这种方法的应用取决于水生纤维素和湖水之间的恒定氧同位素分馏因子，通常报告为 α ¹⁸ O _cell-lw  = 1.028。然而，之前对 α ¹⁸ O _{cell-lw 的}实地评估通常依赖于对湖水 δ ¹⁸ O的一次性测量，这引入了不确定性，因为值可能不代表湖水 δ ¹⁸纤维素合成时的O。我们在加拿大中西部和平-阿萨巴斯卡三角洲 (PAD) 内广泛的湖泊水文梯度中对 α ¹⁸ O _cell-lw = 1.028的使用进行了现场测试，在那里我们将附生生物在人造基质上的纤维素生产限制为括号测量2015 年 5 月下旬和 2015 年 6 月下旬收集的湖水 δ ¹⁸ O。纤维素推断的湖水 δ ¹⁸ O，使用 α ¹⁸ O _{cell-lw 计算}为 1.028 ± 0.0015，与实测湖水 δ ¹⁸的范围一致O 在我们研究的 52 个湖泊中的 36 个（75%）中。对于看起来质量更高的“清洁纤维素”样品（即具有最少成矿物质的样品），一致性提高到 86%。使用 5 月湖水 δ ¹⁸ O (1.0286) 和 5 月至 6 月平均湖水 δ ¹⁸ O (1.0275)计算清洁纤维素样品的平均表观 α ¹⁸ O _cell-lw与 1.028 没有显着差异，但有显着差异，尽管略低于 1.028，使用六月湖水 δ ¹⁸ O (1.0264)。表观 α ¹⁸ O _{cell-lw 的}更紧密对应，使用 5 月和_5-6月平均湖水 δ ^{18 计算}O，建议附生生物快速和早期定植和纤维素生产。对于纤维素和成矿物质混合物的样品，对于这些相应的湖水 δ ¹⁸ O 测量，平均表观 α ¹⁸ O _cell-lw显着低于 1.028 ，但差异很小，可能会导致对纤维素推断的低估在沉积物地层记录中，湖水 δ ¹⁸ O 仅相差 1–2‰。总体而言，在纤维素推断和直接测量的湖水 δ ¹⁸ O之间观察到的强烈一致性支持 α ¹⁸ O _{cell-lw 的应用} = 1.028 ± 0.0015，并为在 PAD 和其他地方的湖泊中使用这种方法进行古水文重建提供了信心。