Composition and spectroscopic characteristics of d

Authors: Yanping Li Shengrui Wang Li Zhang Haichao Zhao Lixin Jiao Yali Zhao Xiaosong He

Publish Date: 2014/05/29

Volume: 14, Issue: 9, Pages: 1599-1611

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Abstract

The content and composition of dissolved organic matter DOM in sediment directly affect nutrient cycling and material exchange in lake ecosystems This study investigated the content and composition of DOM and its fractions in sediments as well as the relationship between the different parameters and nitrogen N forms in DOM The main aim of this study was to evaluate the compositional characteristics of DOM hydrophobic bases HOB hydrophobic acids HOA hydrophobic neutral fractions HON and hydrophilic matter HIM in sediments from Erhai Lake ChinaSeven surface sediment samples with different environmental characteristics were collected The DOM in the sediment was fractionated into HOB HOA HON and HIM using XAD8 resin based on compound hydrophobicity The contents of DOM and its fractions were measured using a TOC analyzer The structural characteristics of DOM and its fractions were investigated using fluorescence spectroscopy and UV–Vis absorbance Correlation analyses were carried out to better understand the relationships between the parameters of the spectral characteristics and the contents of the different N forms in DOM and its fractionsThe content spatial distribution and structure of DOM and its fractions in Erhai Lake sediment were affected by water depth and aquatic plants The DOM content in sediment ranged from 02 to 05 g kg−1 HON accounted for 413 to 857  of DOM whereas HIM constituted 150 to 587  and was significantly negatively correlated with HON R 2  = 0856 P  001 HIM was more dominant than the hydrophobic matter in the southern site but was less abundant in the north and central sites Sediment DOM and its fractions comprised protein and humiclike substances The HOA and HIM comprised humiclike substances which were the most abundant in the southern site1 Hydrophobic fractions are the major components of DOM in the sediments from the seven sites in Erhai Lake 2 DOM and its fractions mainly originated from microbial sources 3 The A 253/A 203 ratio is useful for evaluating the contents of N forms The structure of DOM and its fractions are important in affecting the contents of DON Nitrate NO3N contributes to eutrophication and thus cannot be ignored from studies of Erhai Lake sediment

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