2005年夏季台湾海峡南部有色溶解有机物质吸收特征及其来源初探

Characteristics of Chromophoric Dissolved Organic Matter Absorption in the Southern Taiwan Strait During Summer 2005

2005年7月对台湾海峡南部有色溶解有机物质（CDOM）吸收特性的调查结果表明，CDOM在355nm波段的吸收值（ag（355）．紫外可见分光光度法）变化范围在0．02～0．27m^-1之间，平均0．13m^-,与大洋水体相近；光谱斜率Sg（拟合光谱范围300～500nm）为0．017～O．043nm^-1，平均0．022nm^-1,ag（355）的空间分布特征及其与盐度、叶绿素a的相关关系提示在本次观测期间．该海域有色溶解有机物质主要来源于现场生产，但东山以南近岸表层水中陆源影响为显著．与浮游生物活动有关的紫外区波段（300～350nm）强吸收信号的出现，进一步说明了该海域有色溶解有机物质现场生产机制的重要性．

An investigation of Chromophoric Dissolved Organic Matter（CDOM） in the southern Taiwan Strait （TWS） was carried up during summer 2005. It was found that CDOM absorption coefficients at 355 nm （ag （355）） ,determined by UV-visible spectro-photometer,ranged from 0.02～0.27 m^-1 ,similar to those observed in the open ocean. The spectral slope （Sg） （300～500 nm） varied from 0.017 to 0.043 nm^-1. ag （355） showed a linear,inverse relationship with salinity in the surface water near Dongshan Island. However,for most of the samples with salinity higher than 32（53 samples） ,ag （355） was highly correlated with chlorophyll a with a correlation coefficient（r^2） of 0. 53. Several samples showed obvious absorption peaks in UV-B bands （300～350 nm）, which was probably associated with MAAs released by planktons. It was thus demonstrated that during the period under investigation, CDOM was mainly originated from local production rather than terrestrial input.