神农架大九湖泥炭地孔隙水溶解有机碳特征及其影响因素

溶解性有机碳（Dissolved Organic Carbon, DOC）是泥炭地碳循环的重要组成部分。以往的研究大多集中在北方泥炭地，而对亚热带季风区泥炭地DOC动力学的认识十分有限。利用紫外可见光光谱（UV-Vis）和三维荧光光谱结合平行因子分析法（EEM-PARAFAC）研究了神农架大九湖泥炭地孔隙水的DOC浓度与化学组成及其影响因素。EEM-PARAFAC的结果表明：大九湖泥炭地孔隙水DOC主要包含3种类腐殖质组分。紫外可见光和荧光指标表明，泥炭孔隙水DOC表观分子较小，而芳香度较高。深度剖面数据表明，泥炭孔隙水DOC浓度随深度降低，0~10 cm深度浓度最高为24.16 mg/L，150~160 cm深度浓度最低为9.72 mg/L，并且深层DOC以微生物代谢产生的新鲜有机物为主，具有较低的腐殖化度。此外，氧化还原电位（ORP）与DOC浓度及化学性质关系密切。以上结果表明，在亚热带泥炭地中，微生物来源或受微生物改造的有机物是泥炭孔隙水DOC的重要组成部分；垂向输送或选择性保存是影响该亚热带亚高山泥炭地DOC动力学的重要因素。

Characteristics of Dissolved Organic Matter in Pore Water from the Dajiuhu Peatland,Central China

Dissolved organic carbon (DOC) is an active component in the peatland carbon cycle. While previous studies mostly focus on the northern peatlands, knowledge of the DOC dynamics in peatlands located at the subtropical monsoon region is quite limited. In this study, we investigated the DOC concentration and chemistry in the peat pore water extracted from 15 long term monitoring sites in the Dajiuhu peatland, a typical subtropical peatland in central China, using ultraviolet visible spectrum (UV-Vis) and PARAFAC modeling of excitation emission matrix (EEM). EEM data are fitted into three humic like components. The UV visible and fluorometric indices reveal that the peat pore water samples have relatively small apparent molecular size and high aromaticity. The vertical patterns further indicate that DOC in deeper layers has a relatively important contribution from microbe derived fresh organic matter that is less humified. These results highlight that microbe derived or microbe processed organic matter is an important component of peat pore water in subtropical peatlands, and vertical transport or selective preservation of DOC is an important factor affecting the carbon dynamics in this subtropical sub alpine peatland.