Spatial and temporal variability of solar ultraviolet exposure of coral assemblages in the Florida Keys: Importance of colored dissolved organic matter
Spatial and temporal variability of solar ultraviolet exposure of coral assemblages in the Florida Keys: Importance of colored dissolved organic matter
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DOI：
10.4319/lo.2008.53.5.1909
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发表时间：
2008-09
影响因子：
4.5
通讯作者：
R. Zepp;G. Shank;E. Stabenau;Karen W. Patterson;M. Cyterski;W. Fisher;E. Bartels;S. Anderson
中科院分区：
文献类型：
--
作者：
R. Zepp;G. Shank;E. Stabenau;Karen W. Patterson;M. Cyterski;W. Fisher;E. Bartels;S. Anderson
太阳紫外线(UV)辐射可对热带和亚热带海洋环境中的珊瑚群落产生有害影响，但有关紫外线对珊瑚周围海域渗透的信息很少。在这里，我们提供了1998-2005年间在低键和中键以及干扭矩中获得的紫外域(280[en]400 nm)光学性质的广泛数据集。溶解有机碳的有色组分(DOC；有色溶解有机物质[CDOM])在紫外区的吸收系数比颗粒物的吸收系数大6×~25倍，表明CDOM控制着近岸海域和礁区的紫外线穿透。紫外区CDOM吸收系数(α、CDOM)和DOC值与漫射衰减系数(Kd)高度相关。使用系泊传感器的测量表明，紫外线在低位群岛珊瑚礁区域的穿透能力每天和每天都有很大的变化。日变化与潮汐流有关，潮流将CDOM输送到珊瑚礁区域。在夏季低风期间，第一类蓝水在珊瑚礁附近的层结导致的温度和紫外线穿透率高于混合条件下观察到的温度和紫外线穿透率。这一结果表明，在低风低气压条件下，伴随着海洋变暖而产生的较高紫外线暴露显著地促进了珊瑚的漂白。模拟结果表明，珊瑚礁上水下阳光衰减的变化对紫外线诱导的脱氧核糖核酸(DNA)损伤和珊瑚光合作用的抑制的影响比平流层臭氧层的变化更大。
Solar ultraviolet (UV) radiation can have deleterious effects on coral assemblages in tropical and subtropical marine environments, but little information is available on UV penetration into ocean waters surrounding corals. Here we provide an extensive data set of optical properties in the UV domain (280[en]400 nm) that were obtained during 1998‐2005 at sites located in the Lower and Middle Keys and the Dry Tortugas. Absorption coefficients of the colored component of the dissolved organic carbon (DOC; colored dissolved organic matter [CDOM]) were 6× to 25× larger than particulate absorption coefficients in the UV region, indicating that CDOM controls UV penetration in the inshore coastal waters and reef tract. CDOM absorption coefficients (αCDOM) and DOC were highly correlated to diffuse attenuation coefficients (Kd) in the UV spectral region. Measurements using moored sensors showed that UV penetration at the reef tract in the Lower Keys varies significantly from day to day and diurnally. The diurnal variations were linked to tidal currents that transport CDOM over the reef tract. Summertime stratification of Case 1 bluewaters near the reef tract during periods of low wind resulted in higher temperatures and UV penetration than that observed during well‐mixed conditions. This result suggests that higher UV exposure accompanying ocean warming during low‐wind doldrums conditions significantly contributes to coral bleaching. Modeling results indicate that changes in underwater sunlight attenuation over the coral reefs can affect UV‐induced deoxyribonucleic acid (DNA) damage and inhibition of coral photosynthesis much more strongly than changes in the stratospheric ozone layer.