water@leeds, School of Geography, University of Leeds, LS2 9JT, UK.
Biological and Environmental Sciences, University of Stirling, FK9 4LA, UK.
Sci Total Environ. 2016 Mar 1;545-546:84-94. doi: 10.1016/j.scitotenv.2015.12.101. Epub 2015 Dec 31.
Natural open-water pools are a common feature of northern peatlands and are known to be an important source of atmospheric methane (CH4). Pool environmental variables, particularly water chemistry, vegetation community and physical characteristics, have the potential to exert strong controls on carbon cycling in pools. A total of 66 peatland pools were studied across three regions of the UK (northern Scotland, south-west Scotland, and Northern Ireland). We found that within-region variability of pool water chemistry was low; however, for many pool variables measured there were significant differences between regions. PCA analysis showed that pools in SW Scotland were strongly associated with greater vegetative cover and shallower water depth which is likely to increase dissolved organic carbon (DOC) mineralisation rates, whereas pools in N Scotland were more open and deeper. Pool water DOC, particulate organic carbon and dissolved CH4 concentrations were significantly different between regions. Pools in Northern Ireland had the highest concentrations of DOC (mean=14.5 mg L(-1)) and CH4 (mean=20.6 μg C L(-1)). Chloride and sulphate concentrations were significantly higher in the pools in N Scotland (mean values 26.3 and 2.40 mg L(-1), respectively) than elsewhere, due to a stronger marine influence. The ratio of UV absorbance at 465 nm to absorbance at 665 nm for pools in Northern Ireland indicated that DOC was sourced from poorly humified peat, potentially increasing the bioavailability and mineralisation of organic carbon in pools compared to the pools elsewhere. This study, which specifically aims to address a lack of basic biogeochemical knowledge about pool water chemistry, clearly shows that peatland pools are highly regionally variable. This is likely to be a reflection of significant regional-scale differences in peatland C cycling.
天然开阔水域是北方泥炭地的常见特征，已知是大气甲烷（CH4）的重要来源。池塘环境变量，特别是水化学、植被群落和物理特征，有可能对池塘中的碳循环产生强烈的控制作用。本研究共对英国三个地区（苏格兰北部、苏格兰西南部和北爱尔兰）的 66 个泥炭池进行了研究。我们发现，区域内池塘水化学的变异性较低；然而，对于测量的许多池塘变量，区域之间存在显著差异。PCA 分析表明，苏格兰西南部的池塘与更大的植被覆盖和更浅的水深密切相关，这可能会增加溶解有机碳（DOC）的矿化率，而苏格兰北部的池塘则更开阔和更深。区域间池塘水 DOC、颗粒有机碳和溶解 CH4 浓度存在显著差异。北爱尔兰的池塘具有最高的 DOC（平均值为 14.5mg/L）和 CH4（平均值为 20.6μg C/L）浓度。由于海洋影响较强，苏格兰北部池塘的氯和硫酸盐浓度（分别为 26.3 和 2.40mg/L）明显高于其他地区。北爱尔兰池塘的 465nm 处紫外线吸光度与 665nm 处吸光度的比值表明，DOC 来自未充分腐殖化的泥炭，与其他地区相比，可能会增加池塘中有机碳的生物利用度和矿化度。本研究专门针对缺乏有关池塘水化学的基本生物地球化学知识的问题，清楚地表明泥炭池具有高度的区域变异性。这很可能反映了泥炭地 C 循环在显著的区域尺度上存在差异。
