水生植物腐解过程中溶解性有机质的释放特征

Release Characteristics of Dissolved Organic Matter during Decomposition of Aquatic Plants

通过室内模拟实验,研究了宛山荡生态修复示范区4种水生植物的腐解过程,并分析了其溶解性有机质(DOM)的释放特征。结果表明:4种水生植物腐解均可造成水中溶解性有机碳(DOC)浓度呈先增加再迅速下降的趋势;且随着腐解时间的增加,腐殖质和含不饱和C=C键的芳香族化合物含量升高。腐解前期,水鳖、穗花狐尾藻和水葫芦残体的DOM以富里酸为主,分别在第16、29和22天后以胡敏酸为主;而芦苇残体腐解水中的DOM始终以富里酸为主。利用三维荧光-平行因子法(EEMs-PARAFAC)分析可知,4种水生植物腐解过程中产生了3种荧光有机物,主要包括类腐殖质组分C1、C2和类蛋白质组分C3,且类腐殖质组分占主导地位。通过主成分分析识别到的两个主成分,分别占4种水生植物腐殖水总方差的79.9%、72.6%、83.0%和83.6%,反映了植物腐解过程对水体DOM特征、荧光组分等方面造成的差异。

The decomposition process of four different aquatic plants was investigated and the release characteristics of dissolved organic matter(DOM) in Wanshandang ecological restoration demonstration area was analyzed by laboratory simulation experiments. The concentration of dissolved organic carbon(DOC) in water increased first and then decreased rapidly due to the decomposition of four kinds of aquatic plants. The contents of humus and aromatic compounds containing unsaturated C=C bonds increased with the increase in decomposition time. The DOMs released from Hydrocharis dubia,Myriophyllum spicatum and Eichhornia crassipes residues were dominated by fulic acid in the early stage of decomposition, and humic acid was dominated after 16, 29 and 22 days, respectively. However, the DOM in decomposed water released from Phragmites australis residue was always dominated by fulic acid. According to the results of three-dimensional fluorescence and parallel factor analysis(EEMs-PARAFAC), three kinds of fluorescent organic compounds were produced during the decomposition of four kinds of aquatic plant, which mainly included humus-like components C1, C2 and protein-like components C3, and humus-like substances were dominant. The two principal components identified by principal component analysis accounted for 79.9%, 72.6%, 83.0% and 83.6% of the total variance of the four aquatic plants decomposed water, respectively, which showed the differences in DOM characteristics and fluorescence components of water caused by plant decomposition processes.