胶州湾典型陆源溶解有机氮的生物可利用性研究

Typical Land-Based Dissolved Organic Nitrogenbioavailability in Jiaozhou Bay

针对不同陆源溶解有机氮(DON)组成和生物可利用性的差异,选取大沽河、海泊河污水处理厂、啤酒厂和李村河等典型农业源、城镇生活源、工业源和城镇面源DON开展实验室培养实验。不同陆源DON生物可利用性存在显著差异(p<0.05),其中,城镇生活源和工业源DON生物可利用占比(41%±8%)和降解速率(啤酒厂(0.67±0.08)d^(-1),海泊河污水处理厂(0.51±0.08)d^(-1))最高,城镇面源DON生物可利用占比(37%±10%)和降解速率(0.32±0.03)d^(-1))均略低,而农业源DON生物可利用占比(29%±6%)和降解速率(0.29±0.06)d^(-1))均最低。不同来源DON生物可利用性的差异,反应在细菌生长状况上,二者显著正相关。SUVA_(254)可以用以表征DON的生物可利用性,二者负相关。利用三维荧光光谱可以将陆源DON分为类蛋白和类腐殖质组分,在培养过程中,类蛋白质组分含量逐渐降低,类腐殖质组分含量逐渐升高,说明前者在微生物降解DON中优先被利用,并有可能转化为后者,表现为腐殖化指数升高。

Inview of the differences in the composition and bioavailability of different terrestrial dissolved organic nitrogen(DON),typical agricultural sources,urban living sources,industrial sourcesand urban non-point source of Dagu River,Haibo River Sewage Treatment Plant,Tsingtao Brewery and Licun River DON were used toconductseawater cultureexperiment in JiaozhouBay.There was a significant difference in land-based DON bioavailability from different sources(p<0.05),Among them,urban living source and industrial source DON have the highest bioavailability(41±8)%and degradation rate(breweries(0.67±0.08)d-1,Haibo River sewage treatment plant(0.51±0.08)d-1),the proportion of bioavailable DON(37±10)%and degradation rate(0.32±0.03)d-1 of urban non-point source are all lower,while the proportion of bioavailable DON of agricultural source(29±6)%and degradation rate(0.29±0.06)d-1 were the lowest.The difference in bioavailability of DON from different sources was found to be positively related to the growth of bacteria.SUVA 254 from different sources of water are negatively related to their DON bioavailability and can be used to characterize the bioavailability of DON.Land-based DON can be classified into protein-like and humic-like components by three-dimensional fluorescence spectroscopy.During the culture process,protein-like components gradually decrease,and the content of humic-like components gradually increases,the former is preferentially utilized in microbial degradation of DON and may be converted to the latter,manifested as an increase in the humicification index.