The aim of this study was to determine the effect of drainage on peat properties, porewater chemistry, and peat decomposition proxies in an ombrogenous peatland in the Hudson Bay Lowland (HBL). We anticipated that drainage would change peatland hydrology, vegetation, and biogeochemistry, leading to an increase in peat decomposition. As indicators of peat biogeochemical change and potential proxies for peat decomposition, we compared peat porewater chemistry and in situ nutrient availability of different microforms in a pristine ombrogenous bog, with a bog that has been subject to gradual lowering of the water table by 20 to 80 cm for approximately 7 years prior to, and during, our study. We also examined the chemical composition of peat and peat leachates (organic matter) from Sphagnum and lichen-covered hummocks at each site. Nutrient availability was greater in pools at the drained bog, indicating mineralisation of the dry and bare peat surface. However, our results did not show evidence of significant peat biogeochemical change or advanced decomposition in hummocks at the drained bog, with no difference in nutrient availabilities, peat porewater chemistry, or peat leachate chemistry at the drained and pristine bog. We also found no significant difference in enzyme activity (phenol oxidases) in hummocks at each site, proposed to be an important factor for C loss from peatland ecosystems in drier conditions. Overall, the effects of drainage on peat properties, porewater chemistry, and peat chemical composition at our sites were small and varied for different vegetation-microform types. Although decomposition in drained peatlands is likely constrained by cool temperatures in the HBL, our results suggest that ecohydrological feedbacks at the microform scale may also be important in slowing decomposition in these peatlands.

中文翻译：

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排水对北方泥炭地泥炭特性、孔隙水化学和泥炭分解代理的有限影响

本研究的目的是确定排水对哈德逊湾低地 (HBL) 泥炭地的泥炭特性、孔隙水化学和泥炭分解代理的影响。我们预计排水会改变泥炭地水文、植被和生物地球化学，导致泥炭分解增加。作为泥炭生物地球化学变化的指标和泥炭分解的潜在替代指标，我们比较了原始杂质沼泽中不同微形态的泥炭孔隙水化学和原位养分可用性，沼泽的地下水位逐渐降低了 20 到 80 cm 在我们的研究之前和研究期间大约 7 年。我们还检查了来自每个地点的泥炭和地衣覆盖的小丘的泥炭和泥炭渗滤液（有机物）的化学成分。排干沼泽的水池中的养分利用率更高，表明干燥和裸露的泥炭表面矿化。然而，我们的研究结果并未显示排水沼泽丘陵泥炭生物地球化学发生显着变化或深度分解的证据，排水沼泽和原始沼泽的养分可用性、泥炭孔隙水化学或泥炭渗滤液化学没有差异。我们还发现每个地点的小丘的酶活性（酚氧化酶）没有显着差异，这被认为是干燥条件下泥炭地生态系统碳损失的重要因素。总体而言，排水对我们场地的泥炭特性、孔隙水化学和泥炭化学成分的影响很小，并且对于不同的植被微形态类型来说是不同的。