| Algae organic matters (AOMs) is composed by extracellular algae organic matters (EOMs) and intracellular algae organic matters (IOMs), which shows a significant influence on the composition of natural organic matters (NOMs) in natural water environment. It also shows some negaticve effects on the drinking water treatment. Therefore, it is essential to study the AOMs generation profiles under different environmental conditions to understand the composition and changing of NOMs under algae bloom condition. It is also necessary to provide theoretical supporting forthe development and optimization of drinking water treatment technology.In this study, a typical diatom as Nitzchia palea (N. palea) and a typical green algae as Scenedesmus quadricauda (S. quadricauda) were used as probles to study the AOMs under the differnent nutrition level. To make the medium reach to poor, rich and too rich nutrition level, the concentrations of nitrogen and phosphorus in the medium were changed. The effection of nutritional level and changes of organic components in AOMs have been studied, through the characterization of the total organic matter, spectral characteristics and composition of model compounds. The results showed that the ambient phosphorus was the main factor to promote the growth of N. palea. The ambient nitrogen was the main factor to promote the growth of S. quadricauda. The ambient phosphorus was beneficial to detect total organic carbon (TOC) of N. palea. And the ambient nitrogen was beneficial to detect TOC of S. quadricauda. The maximum value of TOC of N. palea and S. quadricauda reached to 1.3 mg/L and 2.8 mg/L in adaptation phase, respectively. And the ambient phosphorus was also the main factor of detection of N. palea’s amino acids in AOMs. The nitrogen was the main factor of detection of N. palea’s protein and carbohydrate in AOMs. For S. quadricauda, the ambient phosphorus was the main factor of detection of carbohydrate in AOMs and protein in EOMs. The nitrogen was the main factor of detection of amino acids in EOMs. In addition, the derivative method of phenyl isothiocyanate and the 9-fluorenylmethyl chloroformate were used to detect the amino acids compounds and fatty amine compounds in AOMs, respectively. Results showed that the the changes of nitrogen and phosphorus concentration was more significantly affected the detection of amino acids in AOMs of S. quadricauda, which was mainly reflected in the proline and tyrosine. Compared with S. quadricauda, the ambient nitrogen would more promote the using and consumption of fatty amine of N. palea in AOMs.The fluorescence was used to characterize the generation profiles of AOMs of N. palea and S. quadricauda. The excitation and emission matrix fluorescence spectroscopy (EEMs) showed that the aromatic protein substances Ⅰ, aromatic protein substances Ⅱ, fulvic acid, soluble microbial products (SMPs) and humic substances all existed in AOMs of N. palea and S. quadricauda. The aromatic protein substances Ⅰ, aromatic protein substances Ⅱ and SMPs were the main composition in AOMs of N. palea and S. quadricauda. In addition, unlike N. palea, the fulvic acid substance was also the main compositon in AOMs of S. quadricauda. For N. palea, the concentration of aromatic protein decreased with the SMPs concentration increased under different nitrogen and phosphorus. The ambient nitrogen was more beneficial for N. palea to form and detect SMPs in AOMs than that of S. quadricauda. The ambient phosphorus was more beneficial to form and detect fulvic acid. And the synchronous fluorescence result showed that the ambient nitrogen was more beneficial for S. quadricauda to change the aromatic structure of proteins-like and humic acids-like material in AOMs. In addition, the method of UV spectroscopy has been used to characterize the AOMs of N. palea, showing that carboxylic acid and ester, phenylacetic acid and 2,5-dihydroxyterephthalic existed in EOMs of N. palea. |
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