厦门湾沉积物间隙水中CDOM的荧光特性及其分布研究

Fluorescence characteristics of chromophoric dissolved organic matter and its distribution in sediment pore waters from Xiamen Bay

研究了2003年4月从厦门湾九龙江口、西海域及同安湾采集的表层沉积物及柱状样间隙水中有色溶解有机物（CDOM）的荧光特性及其水平与垂直分布特征．结果表明，间隙水CDOM中均观测到类腐殖质与类色氨酸两类荧光．它们在表层沉积物间隙水中的相对含量均以九龙江口靠近浮宫红树林区的站位最高，同安湾及西海域养殖区各站位次之，分别反映了河口区红树林生态系以及养殖活动的影响；西海域靠近东渡码头的站位两类荧光的相对含量最低，系受疏浚活动影响所致．表层沉积物间隙水中两类荧光的相对含量均远高于底层水，暗示表层沉积物可成为上覆水体CDOM的一个重要来源．大多数站位间隙水中类腐殖质荧光的相对含量随深度增加而渐增，反映了CDOM在缺氧环境下的成岩作用过程．多数站位在3—6cm深度处出现类色氨酸荧光峰值，随后递减，反映了近表层沉积物中细菌等微生物活动对蛋白质的降解作用．

Fluorescence characteristics of chromophoric dissolved organic matter（CDOM） and its distribution in sediment pore waters collected from Xiamen Bay （Jiulongjiang Estuary, West Xiamen Harbor and Tong＇an Bay） in April 2003 were studied. Both humic-like and tryptophan-like fluorescence were observed in all pore water samples. The maximal relative intensities of both fluorescence in surface sediment pore water were found in the site close to Fugong mangrove zone in Jiulongjiang Estuary, and the sites near the aquaculture region of Tong＇ an Bay and West Xiamen Harbor also showed higher fluorescence intensities, reflecting the effects from the mangrove ecosystem and aquaculture activities, respectively. Both fluorescence intensities were lowest near to the Dongdu Harbor in West Xiamen Harbor, due to the influence of dredging activity. Both fluorescence intensities in surface sediment pore waters showed a factor of 7 -50 higher than the corresponding intensities in bottom waters, suggested that the sediment might be an important source of CDOM in its upper waters. Humic-like fluorescence increased with sediment depth at the most sites, indicating that CDOM undergoes diagenetic processes in anoxic environment. The tryptophan-like fluorescence had peak values at 3-6 cm depth and then showed decrease tendency for several sites, which suggests the effects of microorganism （e. g. bacteria） on the biologic degradation of protein near surface sediments.