Spatial and temporal variability of colored dissolved organic matter absorption properties in the Taiwan Strait

• Published in: Acta oceanologica Sinica 2012-09, Vol.31 (5), p.98-106
• Main Authors: Lin, Hui, Guo, Weidong, Hu, Minghui, Lin, Cai, Ji, Weidong
• Format: Article
• Language: English
• Subjects: Absorption; Absorption coefficient; Absorptivity; Aromaticity; Biological activity; Chemistry; Climatology; Coastal currents; Colour; Dissolved organic matter; Distribution; Earth and Environmental Science; Earth Sciences; Ecology; Engineering Fluid Dynamics; Environmental Chemistry; Hydrology; Marine; Marine & Freshwater Sciences; Mass movement; Molecular weight; Oceanography; Offshore; Optical properties; Rivers; Seasonal variation; Seasonal variations; Seawater; Straits; Summer; Temporal variations; Variability; Water masses; Wavelengths; Winter; 台湾海峡; 吸收特性; 吸收系数; 季节性变化; 时间; 溶解有机物; 空间; 近海地区
• ISSN: 0253-505X; 1869-1099
• DOI: 10.1007/s13131-012-0240-x

Spatial and temporal variability of the absorption properties of colored dissolved organic matter （CDOM） in the Taiwan Strait was investigated in summer （July to August of 2006） and winter （from December 2006 to January of 2007） seasons. The CDOM absorption coefficient at 280 nm （a 280 ） showed a decreasing trend from nearshore to offshore areas while the spectral slope coefficient parameter calculated between wavelengths 275–295 nm （S 275 295 ） showed an increase, indicative of decreasing aromaticity and molecular weight of the CDOM. The average a 280 in winter （1.47 ± 0.50 m ^-1 ） was significantly higher than in summer （1.10 ± 0.41 m ^-1 ）, while the average S 275 295 in winter （26.7 ± 5.2 μm^- 1 ） was significantly lower than in summer （30.6 ± 5.5 μm^- 1 ）, demonstrating clear seasonal variation in CDOM abundance and properties in the Taiwan Strait. A three-end- member conservative mixing model showed that local terrestrial CDOM inputs from several rivers along the western coast were small （〈5%）. However, the distribution of CDOM in the Taiwan Strait is mainly controlled by water mass movement [i.e., the Zhe-min Coastal Current （ZCC） and the Kuroshio Branch Current （KBC） in winter and the South China Sea Water （SCSW） in summer]. Biological activity was also an important factor affecting the distribution of CDOM in the offshore region in summer months.