This study compared soil organic carbon (SOC) in wetlands dominated by native and one invasive plant specie to better understand how short-term Spartina alterniflora colonization affected carbon circulation in the Yellow River Delta (YRD). Freshwater marsh dominated by Phragmites australis (FM) had the highest SOC, total nitrogen (TN), and water-extractable organic carbon (WEOC) contents, whereas SOC contents varied only slightly among salt marshes covered by Suaeda salsa (SM2), S. alterniflora (SM3) and bare flat (MD). Invasion by S. alterniflora substantially changed the molecular characteristics of SOC. The spectral characteristics of Fourier-transform infrared spectroscopy (FTIR) of humic acids (HAs) were similar from 4000 to 1800 cm⁻¹ but differed greatly from 1800 to 1000 cm⁻¹ among four wetlands. Pyrolysis-gas chromatography/mass spectrometry technology (Py-GC/MS) was used to characterize molecular fingerprints of HAs. Aliphatics (27.38%), lignin (16.64%), nitrogen-containing compounds (Nc) (16.16%), polysaccharides (16.93%), and phenol (13.42%) were dominant in FM, and aliphatics, alkyl, and Nc were primary in HAs from MD, SM2, and SM3. Lignin moieties were only found in HAs from FM and SM3, which accounted for about 16.64% and 1.6% of the total ion current, respectively. The absorption bands of the FTIR spectrum around 3340 and 1650 cm⁻¹ in FM samples were much larger than those in the other three wetlands. However, the ratio of the peak areas at 1620 and 2930 cm⁻¹ (R_1620/2930) in SM3, was lower than that in MD and SM2, and it meant carbon in SM3 was less stable. Proportions of lignin and phenol moieties to total ion counts (TIC) in MD and SM2 were 3.3% and 3.4%, while these proportions in FM and SM were 30% and 7.5%, respectively. It showed S. alterniflora invasion into salt marsh would increase SOC contents and its stability, while it will inverse if freshwater marsh was supplanted by S. alterniflora in the YRD.

这项研究比较了以原生物种和一种入侵植物为主的湿地中的土壤有机碳（SOC），以更好地了解互花米草的短期定殖如何影响黄河三角洲（YRD）的碳循环。以芦苇（FM）为主的淡水沼泽具有最高的SOC，总氮（TN）和水可提取的有机碳（WEOC）含量，而SOC含量仅在Suaeda salsa（SM2），S覆盖的盐沼中变化很小。互花米草（SM3）和裸露扁平草（MD）。互花米草的入侵大大改变了SOC的分子特性。腐殖酸（HAs）的傅立叶变换红外光谱（FTIR）的光谱特征在4000至1800 cm ^-1之间相似，但在四个湿地之间在1800至1000 cm ^-1之间有很大差异。热解-气相色谱/质谱技术（Py-GC / MS）用于表征HA的分子指纹。脂肪族化合物（27.38％），木质素（16.64％），含氮化合物（Nc）（16.16％），多糖（16.93％）和苯酚（13.42％）在FM中占主导地位，而脂肪族，烷基和Nc是主要的在MD，SM2和SM3中的HA中。木质素部分仅在FM和HA中发现SM3分别占总离子流的约16.64％和1.6％。围绕3340和1650厘米FTIR光谱的吸收带^-1在FM样品比那些在其他三个湿地大得多。但是，SM3中在1620和_2930cm ^-1（R _1620/2930）处的峰面积比低于MD和SM2中的峰面积比，这意味着SM3中的碳不稳定。木质素和酚部分在MD和SM2中占总离子数（TIC）的比例分别为3.3％和3.4％，而FM和SM中的比例分别为30％和7.5％。表明互花米草浸入盐沼中会增加土壤有机碳含量及其稳定性，而如果长三角地区的互花米草替代淡水沼泽则会相反。