运用三维荧光-平行因子分析(EEMs-PARAFAC)和室内生物培养实验, 分析了洪泽湖和骆马湖有色可溶性有机物(CDOM)生物降解特征对不同水文情景的响应。 结果表明, (1)平行因子分析得到3类荧光组分, 类腐殖质C1、 类色氨酸C2和类酪氨酸C3。 (2）经28天生物培养后, 枯水期洪泽湖、 骆马湖溶解性有机碳DOC生物可利用性(BDOC, 分别为17%±4%, 15%±4%)高于丰水期(分别为5%±5%, 10%±7%), 且枯水期%BDOC高值主要分布于入湖口区域。 (3）枯水期两湖泊比紫外吸收系数SUVA254和类腐殖质C1荧光强度显著高于培养前, 即ΔSUVA254和ΔC1为负值, 而类酪氨酸荧光强度显著低于培养前, 即ΔC3为正值, 表明了枯水期类酪氨酸生物可利用性较高, 产生了较为稳定的类腐殖质, 增加了样品的腐殖化程度。 (4）BDOC和%BDOC分别与ΔSUVA254有较好的负相关性, BDOC及%BDOC与ΔC3, %ΔC3均有较好的正相关性。 这意味着两个湖泊CDOM组成直接影响其生物可利用性。

We investigated the bioavailability characteristics of chromophoric dissolved organic matter (CDOM) in different hydrological scenarios of Lake Hongze and Lake Luoma using bio-incubation experiments coupled with excitation-emission matrices and parallel factor analysis (EEMs-PARAFAC). The results showed that (1) Three fluorescent components were obtained using PARAFAC, including a humic-like C1, a tryptophan-like C2 and a tyrosine-like C3. (2) After 28 days of bio-incubation, the bioavailability of dissolved organic carbon (BDOC) in Lake Hongze and Lake Luoma in dry season (17%±4% and 15%±4%) was higher than that in flood season (5%±5% and 10%±7%), and the high %BDOC values of the two lakes were mainly distributed in the inflowing river mouths. (3) The specific absorbance at 254 nm SUVA254 and humic-like components in the two lakes during dry season was significantly higher than that pre-bio-incubation, and ΔSUVA254 and ΔC1 were negative. The tyrosine-like component was significantly lower than that pre-bio-incubation and ΔC3 was positive, indicating that the microorganisms preferentially utilized the less stable tyrosine-like component in the dry season, and produced more stable humic-like C1 and also increased the humification of the samples collected from the two lakes. (4) There were significant negative correlations between BDOC, %BDOC and ΔSUVA254, ΔC3, %ΔC3, respectively. These results indicated that CDOM optical composition directly affects its bioavailability in the two lakes.