呼伦湖水体悬浮颗粒物中有机质的赋存特征及来源解析

SPOM（suspended particulate organic matter，悬浮颗粒物中的有机质）是地表水体中有机质的重要组分之一，在全球碳循环和水体富营养化过程中发挥着重要作用.采用连续提取法、δ13C（碳稳定同位素）、三维荧光光谱和平行因子分析技术对呼伦湖夏季SPOM的含量、组分、荧光特性、污染来源及生物有效性进行系统研究.结果表明:①SPOM（以碳质量计）在14.4~31.5 g/kg之间，其中HM（提取残渣）为SPOM的主要组分，占SPOM总量的61.2%.②SPOM中WEOM（水提态有机质）含有类富里酸组分（C1）、类腐殖酸组分（C2）和类色氨酸组分（C3）3个荧光组分，类腐殖质组分（C1+C2）和类蛋白质组分（C3）对总荧光强度的贡献分别为70.4%和29.6%.③SPOM的C/N〔总有机碳（TOC）浓度与总氮（TN）浓度的比值〕和δ13C的值分别在7.53~15.2和-27.2‰~-26.1‰之间.利用C/N和δ13C端元混合模型计算陆源对SPOM的平均贡献率分别为67.2%和68.9%，结果相近.④WEOM的HIX值在4.09~7.40之间，腐殖化程度较高，生物可利用性较差.研究显示，呼伦湖中SPOM以难降解的腐殖质组分为主，腐殖化程度较强，生物可利用性较低，但随着温度升高，预估自生源SPOM的贡献将增大，可能导致其生物可利用性升高，需引起足够的重视. 

Characteristics and Sources of Suspended Particulate Organic Matter in Lake Hulun

Suspended particulate organic matter (SPOM) is one of the important components of organic matter in surface water, and plays an important role in the global carbon cycle and water eutrophication. Sequential extraction, carbon stable isotope (δ13C), three-dimensional excitation-emission matrix fluorescence spectra and parallel factor analysis methods were used to systematically study the content, components, fluorescence characteristics, sources and bioavailability of the SPOM in Lake Hulun in summer. The results indicated that the total amount of SPOM (measured by content of carbon) ranged from 14.4 to 31.5 g/kg, and extraction residue (HM) was the main component, accounting for 61.2% of the total SPOM. Three fluorescence components were found in water extracted organic matter (WEOM) in SPOM, including fulvic-like component C1, humic-like component C2 and tryptophan-like component C3. The contribution of humic component (C1+C2) and protein-like component C3 to the total fluorescence intensity was 70.4% and 29.6%, respectively. The values of C/N (ration of total organic carbon to nitrogen concentration) and δ13C in SPOM ranged from 7.53 to 15.2 and -27.2‰ to -26.1‰, respectively, indicating that the SPOM probably came from terrestrial sources. Based on the information of C/N and δ13C, similar results of the contributions of exogenous sources to SPOM (67.2% and 68.9%, respectively) were obtained. The HIX value of WEOM was between 4.09 and 7.40, with a strong degree of humification and poor bioavailability. However, the endogenous contribution to SPOM has gradually increased recently which may lead to enhanced bioavailability of SPOM and deserve more attention.