洱海沉积物孔隙水中溶解有机质的三维荧光光谱特征

THREE-DIMENSIONAL EXCITATION EMISSION MATRIX FLUORESCENCE SPECTROSCOPIC CHARACTERIZATION OF DISSOLVED ORGANIC MATTER IN SEDIMENT PORE WATER IN LAKE ERHAI

文章应用三维荧光光谱技术对洱海沉积物孔隙水中的溶解有机质进行了研究。结果表明,所有样品均含有4个明显的荧光峰,其中A和C为类腐殖酸荧光,B和D为类蛋白荧光。荧光强度在沉积物-水界面特别强,在1cm处急剧下降,之后随着沉积深度呈上升趋势。孔隙水溶解有机质均具有强的类蛋白荧光,揭示了溶解有机质中含有大量色氨酸、酪氨酸等芳环结构的类蛋白物质,并且在早期成岩过程中随着沉积深度呈积累趋势;类蛋白荧光与类腐殖酸荧光之间具有一定的相关关系,r(A,C)值在0.94-1.79之间,随着沉积深度逐渐下降,r(D,B)值在0.9-1.75之间,与r(A,C)值极为接近,且随着沉积深度有着类似的变化趋势,说明在洱海沉积物孔隙水中,r(D,B)与r(A,C)之间具有一定的相关性。

Three-dimensional excitation emission matrix fluorescence spectroscopy (3DEEM) was used to investigate the fluorescence properties of dissolved organic matter (DOM) in sediment pore water in Lake Erhai. Of all the samples analyzed in this study, pore water DOM was found to contain four fluorescence peaks. Peak A and C represent humic-like fluorescence, whereas peak B and D represent protein-like fluorescence. The fluorescence intensity of these peaks were all strong at the sediment-water interface with a sharp decrease at the depth of 1cm, then increased with depth. The strong protein-like fluorescence found in the sediment pore water DOM in lake Erhai indicated the existence of some protein-like substances that were released from sediment to pore water. Protein-like fluorescence increased with depth, suggesting that a conservative behavior during early diagenesis. The values of r(A,C) ranged 0.94-1.79, r(D,B) ranged 0.90 ~ 1.75. Both r(A,C) and r(D,B) decreased slightly with depth and their close values, suggesting a strong relationship between them for the DOM samples from sediment pore water in Lake Erhai.