辽河东西支流与干流水体光学特性和组分对比研究

通过对东、西辽河和辽河干流有色溶解有机物(CDOM)吸收特性和荧光特征以及溶解有机碳(DOC)浓度的分析,对比研究不同子流域CDOM的光学特性差异,并分析影响CDOM与DOC浓度的主要因素.对比研究发现,辽河干流CDOM与DOC相关性(R=0.89,P0.01)高于西辽河(R=0.81)与东辽河(R=0.75).总悬浮物浓度(TSM)和总碱度与不同子流域CDOM/DOC相关性较高.不同流域内CDOM与DOC的浓度变化较大,西辽河CDOM和DOC浓度明显高于东辽河和辽河干流.流域内土地利用、气候条件对两者浓度的影响显著,林地和CDOM及DOC浓度存在显著负相关(R=-0.41,-0.56),即林地面积越大,CDOM和DOC浓度越低;而农田与两者存在正相关(R=0.40,0.32),农田面积越大,相应的CDOM和DOC浓度越高;降雨量与CDOM和DOC呈现明显的负相关(R=-0.53,-0.38),说明降雨对河流CDOM的稀释作用较大.对于CDOM荧光强度Fn(355)与CDOM浓度来说,在每个子流域两者均存在较好的相关性,特别是西辽河流域(R=0.96,P0.01).CDOM的三维荧光光谱发现,东、西辽河及辽河干流均表现出较强的类腐殖酸荧光峰(A峰和C峰),同时辽河干流表现出很强的类蛋白质峰(T峰).CDOM的吸收斜率(S)以及基于荧光光谱的FI和HIX表明东、西辽河和辽河干流CDOM的主要来源是外源高等植物输入的大分子量DOM,但是,西辽河和辽河干流CDOM的分子量要小于东辽河CDOM组成物质.

Comparative characterization of optically active components in waters from the east/west tributaries and the stem of Liaohe River

Comparative analyses about the differences of optical characteristics and composition of riverine waters in the East/West tributaries and the stem of Liaohe River were conducted and the influenced factors impacting on chromophoric dissolved organic matter (CDOM) and dissolve organic carbon (DOC) in different sub-watersheds were examined based on the absorption and fluorescent optical properties. Relationship between CDOM absorption and DOC concentration in the stem of Liaohe River exhibited the best (R = 0.89, P < 0.01) compared with that in the East Liaohe River (R = 0.75) and the West Liaohe River (R = 0.81). Close relationships between two water qualities (total suspended matter TSM] and total alkalinity) and ratios of CDOM and DOC (CDOM/DOC) were obtained in this investigation. CDOM and DOC concentrations showed great variability in different sub-watersheds. CDOM and DOC concentrations in West Liaohe River were higher than that in East and the stem of Liaohe River. Land use/cover and climate conditions exerted great influences on CDOM and DOC. Significant negative correlations were obtained between forest area and CDOM and DOC, with the R = -0.41 and -0.56respectively. Positive correlations were observed between cropland area and CDOM and DOC (R = 0.40 for CDOM and R =0.32 for DOC). Furthermore, negative correlations were obtained between precipitations and CDOM and DOC, with the R = -0.53 and -0.38 respectively, which demonstrated that dilute effect of rainfall exhibited great influence on CDOM and DOC concentrations. Moreover, relationships between Fn (355) and CDOM absorption in different sub-watersheds showed strong correlations, especially in the West Liaohe River (R = 0.96, P < 0.01). All the samples exhibited fairly strong humic-like fluorophore (fluorophore A and fluorophore C) in the fluorescence excitation-emission matrices (EEMs). Meantime, samples in the main stem of Liaohe River showed strong protein-like fluorophore (fluorophore T). Main sources of CDOM in the studied rivers were terrestrial (allochthonous) origins, which showed the high weight molecular substances based on the S, FI and HIX values. However, molecular weights in West Liaohe River and the main stem of Liaohe River were inclined to be lower than that in the East Liaohe River.