BIOAVAILABILITY AND COMPONENT STRUCTURE OF DISSOLVED ORGANIC NITROGEN FROM CHICKEN MANURE AT DIFFERENT DEGRADATION STAGES IN NATURAL SEAWATER
Terrestrial dissolved organic nitrogen(DON)is an important nitrogen source in nearshore environments,and its impact on marine ecosystems is related to its inherent bioavailability,composition,and structure.However,it is difficult to characterize the constantly changing bioavailability and structure of DON during natural seawater aging.By focusing on a type of DON derived from chicken manure,a year-long natural seawater degradation experiment was performed to measure and characterize the physicochemical parameters and spectral features of DON across various degradation stages.Results show that of the total bioavailable DON(BDON)by culture time,the labile bioavailable DON(LBDON,0～12 days),half-labile bioavailable DON(HLBDON,12～80 days),and refractory bioavailable DON(RBDON,80～365 days)fractions occupied 51.41％,31.79％,and 2.63％,respectively.Notably,LBDON and HLBDON were mainly composed of three-dimensional fluorescent tryptophan T component and soil fulvic acid D component,and amine functional groups were the main components in structure.In contrast,RBDON was mainly composed of visible light fulvic acid C1 component,including amine,hydroxyl,aromatic,and carboxyl/ester functional groups.The refractory DON(RDON)consisted of mainly three-dimensional fluorescent ultraviolet region fulvic acid A component and humic acid like E component,including alkyne,aromatic ring,and carboxyl/ester groups in structure.Compared to BDON,RDON showed significant increases in aromaticity by 89.8％,hydrophobicity by 86.5％,and humification by 39.2％.This study contributed to a better understanding of the bioavailability and ecological impacts of terrestrial DON in the ocean.
dissolved organic nitrogen(DON)bioavailabilitycomponent structure characteristicsland sourceLaizhou Bay
万方数据
维普
