湖泊沉积物有机质的连续提取与荧光光谱特征分析

采用化学连续提取与三维荧光光谱相结合的方法研究了蠡湖沉积物中可提取有机质的组成、结构和空间分布特征,并探讨了可提取态有机质组分与可交换态氮和弱吸附态磷之间的相关关系.结果表明,蠡湖沉积物中有机质含量为5.59~22.11 g·kg~(-1)(以C计),均值为12.28g·kg~(-1),其中水可提取态有机质(WSOM)、富里酸(FA)、胡敏酸(HA)和胡敏素(HM)的比例分别为5.14%、11.81%、9.63%和73.42%,空间上呈现由西向东逐渐递增,湖岸大于湖心的分布趋势.WSOM鉴别出3个荧光组分,以类氨基酸荧光峰(W-C1)占优势,占总荧光强度的比例为42.49%;FA鉴别出2个荧光组分,以富里酸荧光峰(F-C2)为主,比例为67.63%;HA的3个荧光峰中,以类胡敏酸荧光峰(H-C1和H-C3)为主,两者之和的比例为71.55%.多元回归统计表明,可提取有机质组分与游离态氮和易解析态磷含量之间均显著正相关,且与氮的相关性系数大于与磷,反映了可提取有机质与可交换态氮的关系更为密切,可用于指示沉积物生物可利用性氮磷的污染状况.

Sequential extractions and fluorescene spectroscopy characterization of organic matter in the Lake Sediment

Chemical sequential extractions and three dimensional fluorescence spectroscopy were applied to analyze the composition, structure and spatial distribution of the extractable organic matter of sediment in Lihu lake. the relationship between the exchangeable nitrogen, the weak adsorbed phosphorus and extractable organic matter component are further discussed. The results show that the organic matte contents in the sediment ranged from 5.59~22.11 g ·kg^-1, with the mean value of 12.28 g·kg^-1. The water soluble organic matter (WSOM), fulvic acid (FA), humic acid (HA) and humin (HM) accounted for the total organic matter were in the proportion of 5.14%, 11.81%, 9.63% and 5.14%, respectively. In spatial, WSOM, FA, HA and HM contents decrease from east to west in Lihu Lake, and the intensity in the lakeside area is higher than that in the center area. There are three fluorescence components identified of WSOM, while amino-like fluorescence (W-C1) mainly existed with 42.49% of the total fluorescence intensity. There were two fluorescence components identified of FA, while fulvic acid fluorescence (F-C2) is predominant at 67.63%. There are three fluorescence components in the HA, in which the humic acid fluorescence (H-C1 and H-C3) is the primary componentwith the abundance of 71.55%. Depending on the multiple regression analysis, extractable organic matter components are significantly correlated with the exchangeable nitrogen and the weak adsorbed phosphorus. The correlation coefficient between exchangeable nitrogen and extractable organic matter fluorescent components is greater than that between weak adsorbed phosphorus and extractable organic matter. In conclusion, the extractable organic matter is more closely related to the exchangeable nitrogen, provides to indicate the pollution status of the bioavaliable Nitrogen and Phosphorus in sediments.