Ultraviolet Light and Temperature Effects on Reef-Building Corals

对1987年全加勒比大规模珊瑚礁的最新解释 漂白事件表明，海洋表面温度的升高 和增强紫外线穿透是主要的 促成因素。 本项目将对此进行调查 通过进行一系列实验， 划分了紫外线和温度的相对影响， 对珊瑚的生长和生存有什么影响 适当的实验 紫外线照射水平将基于以下数据：i） 1989年记录的长期紫外线通量测量，ii）初步 实地实验评估紫外线照射增强的影响，以及 ㈢在晴朗的热带海洋中进行紫外线测量 沃茨。 实验珊瑚（Montastrea annularis和Agaricia 拉马克）在户外举行的紫外线透明丙烯酸水族馆将 经受两种UV光方案：1）环境UV通量，基于 从既往长期监测（对照）中获得的值，以及 2)最大紫外线通量模拟发生在 1987年的白化事件（根据初步实地调查结果 确定导致珊瑚压力的紫外线水平的实验，或 处理，珊瑚将受到三个控制 温度范围：28 ℃（对照）、30 ℃和31 ℃（峰值或接近峰值） 1987年加勒比海珊瑚礁记录的最高温度） 长达两个月 将通过以下方式评估治疗效果： 量化菌落颜色，叶绿素浓度， 虫黄藻密度、有丝分裂指数和浓度 紫外线阻断色素形成珊瑚组织（使用HPLC）。 一 第二个实验将分离差异，并结合， UV-A和-B的影响 除了这些实验，我们 将在大开曼岛建立一个长期的紫外线监测计划 开曼岛（NOAA Aquarius栖息地计划所在地） 并将这些发现与观察到的内部和 种间差异的紫外线色素浓度， 沿着一个深度梯度的珊瑚礁。 这些数据将构成 这是一个重要的基线，可用于记录每年的情况， 紫外线强度的十年变化， 消除平流层臭氧。

Recent explanations for the 1987 Caribbean-wide, mass coral bleaching event suggest that increased sea surface temperatures and enhanced ultraviolet light penetration were major contributing factors. This project will investigate this hypothesis by conducting a series of experiments designed to partition the relative effects that UV light and temperature have on coral growth and survivorship. Appropriate experimental levels for UV irradiation will be based on data derived from: i) long-term UV flux measurements recorded in 1989, ii) preliminary field experiments assessing effects of enhanced UV exposures, and iii) UV measurements to be taken in clear tropical oceanic waters. Experimental corals (Montastrea annularis and Agaricia lamarcki) held outdoors in UV-transparent acrylic aquaria will be subject to two UV light regimes: 1) ambient UV flux, based on values obtained form prior long-term monitoring (controls), and 2) maximum UV flux simulating the conditions that occurred during the 1987 bleaching event (based on results from preliminary field experiments identifying UV levels leading to coral stress, or on treatment, corals will be subjected to three controlled temperature regimes: 28oC (control), 30oC and 31oC (peak or near- peak temperatures recorded on reefs in the Caribbean during 1987) for up to two months. Treatment effects will be assessed by quantifying changes in colony color, chlorophyll concentration, zooxanthellae densities, mitotic indices and the concentrations of UV blocking pigments form coral tissues (using HPLC). A second experiment will separate the differential, and combined, effects of UV-A and -B. In addition to these experiments, we will establish a long- term UV monitoring program on Grand Cayman Island, Cayman Island (site of the NOAA Aquarius habitat program) and will relate these findings to observed intra- and interspecific differences in concentrations of UV pigments in reef corals along a depth gradient. These data will constitute an important baseline that can be used to document yearly and decadal changes in UV light levels resulting from continued deletion of stratospheric ozone.