Effects of Ultraviolet Radiation on the Biology of Caribbean Reef Corals

最近的研究表明，紫外线辐射可以穿透热带珊瑚礁的相当深的地方。长期的海面平静造成的持续高水平的紫外线穿透，已显示会引起压力，导致共生虫黄藻在造礁珊瑚中丧失（即白化）。这些条件可能在很大程度上促成了1987年和1990年在加勒比观察到的区域性大规模珊瑚白化事件。这项计划将继续监测紫外线辐射的穿透情况、海水温度，以及受紫外线辐射的珊瑚的复原情况。此外，该项目将扩大，以评价紫外线辐射对主要珊瑚品种的早期生活史阶段，即浮藻幼虫和新吸收的幼体的影响。虽然在低纬度地区，紫外线辐射的增加预计是最小的，但全球变暖所预测的平静海况增加的频率将导致水柱清晰度提高和紫外线穿透率提高，从而对珊瑚礁珊瑚产生负面影响。该项目通过实验确定幼虫和幼珊瑚可耐受的最大紫外线强度，将深入了解当前紫外线辐射强度在限制招募和塑造后续珊瑚群落结构方面所起的作用。

Recent studies indicate that ultraviolet radiation can penetrate to considerable depths on tropical reefs. Persistent high levels of UV penetration, resulting from extended periods of calm sea conditions, have been shown to induce stress leading to the loss of symbiotic zooxanthellae (i.e., bleaching) in reef-building corals. These conditions may have contributed significantly to the regional mass coral bleaching events observed in the Caribbean during 1987 and 1990. This project will continue monitoring penetration of UV radiation, sea temperatures, and recovery of coral exposed to UV radiation. In addition, the project will be expanded to evaluate the effects of UV radiation on the early life-history stages, namely planula larvae and newly-recruited juveniles, of predominant coral species. While increases in UV radiation are predicted to be minimal at low latitudes, increased frequency of calm sea conditions predicted by global warming will lead to enhanced water column clarity and high UV penetration with subsequent negative effects on reef corals. This project, by experimentally defining the maximum UV intensities that can be tolerated by larval and juveniles corals, will provide insight into the role that current intensities of UV radiation play in limiting recruitment and shaping subsequent coral community structure.