Peatland reservoirs are global hotspots for drinking water provision and are likely to become more important as demand per capita rises and the climate changes. Dissolved organic carbon (DOC) is associated with harmful disinfection byproducts and reduced aesthetic quality, and its removal is the major treatment cost. Littoral zones are known to be disproportionately important for DOC production through macrophyte inputs, and such communities are predicted to expand with warming in northern regions. However, little is known about autochthonous DOC contributions and their response to climatic change. Here we exposed mesocosms to elevated CO₂ (eCO₂), warming and a combined treatment across a trophic gradient. Regression analysis indicated that while sediments, macrophytes, and phytoplankton are important DOC sources (P < 0.05), benthic algal biomass showed the strongest relationship with DOC (P < 0.05), suggesting it is an underestimated source. DOC removal indicators, namely phenol oxidase (depolymerization) and respiration (mineralization) were inversely related to DOC concentration in oligohumic (P < 0.05) and oligotrophic (P < 0.1) systems, suggesting heterotrophic processes are important in DOC removal. DOC concentrations increased across all systems (P < 0.05), irrespective of trophic status, due to increased photoautotrophic inputs (macrophyte, pelagic, and benthic algae) under eCO₂, warming, and combined scenarios, with inhibited depolymerization and mineralization under eCO₂, even when combined with warming (P < 0.05 and P < 0.05 excepting the oligo-mesotrophic reservoir P < 0.1 respectively). Increased DOC loads of all fractions, regardless of provenance, are predicted in a future climate and, thus, investment in techniques to remove a greater range of DOC fractions is proposed to help “future proof” drinking water supplies.

中文翻译：

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气候变化对泥炭地水库的影响：DOC 的观点

泥炭地水库是全球饮用水供应热点，随着人均需求的增加和气候变化，泥炭地水库可能变得更加重要。溶解有机碳 (DOC) 与有害的消毒副产物和降低的美学质量有关，其去除是主要的处理成本。众所周知，沿海地区对通过大型植物投入生产 DOC 的重要性不成比例，预计这些群落会随着北部地区的变暖而扩大。然而，对本土 DOC 的贡献及其对气候变化的反应知之甚少。在这里，我们将中胚层暴露于升高的 CO ₂ (eCO ₂），变暖和跨越营养梯度的联合治疗。回归分析表明，沉积物、大型植物和浮游植物是重要的 DOC 来源（P  < 0.05），底栖藻类生物量与 DOC 的关系最强（P  < 0.05），表明它是一个被低估的来源。DOC 去除指标，即酚氧化酶（解聚）和呼吸（矿化） 与贫腐（P < 0.05）和贫营养（P  < 0.1）系统中的DOC 浓度呈负相关，表明异养过程在 DOC 去除中很重要。所有系统中的 DOC 浓度均增加（P <0.05），而不论营养状态，由于生态下增加的光自养输入（水生植物，浮游，和底栖藻类）₂，升温，并结合场景中，用Eco下抑制解聚和矿化₂，即使当用温热（组合P  < 0.05 和P  < 0.05，除了贫中营养水库P  < 0.1 分别）。在未来的气候中，预测所有馏分的 DOC 负荷增加，无论其来源如何，因此，建议投资于去除更大范围 DOC 馏分的技术，以帮助“面向未来”的饮用水供应。