Bleaching of Symbiotic Algae (Zooxanthellae) and their Invertebrate Hosts: Causes and Mechanisms

共生藻类（虫黄藻）及其无脊椎动物宿主的白化：原因和机制

• 批准号: 9203327
• 负责人: William Fitt
• 金额: $ 10万
• 依托单位: University of Georgia Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-06-01 至 1996-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9203327&HistoricalAwards=false
• 关键词: Bleaching; Symbiotic; Algae; Zooxanthellae; their

Bleaching, the loss of symbiotic dinoflagellates)="zooxanthellae" hereafter) of their pigments, of reef corals and other invertebrates has become a world-wide problem in tropical marine ecosystem, linked by some researchers to global warming. The results of bleaching have potentially devastating environmental, ecological and economic effects in the Caribbean, IndoPacific, an other tropical marine areas. Though there is some experimental work showing involvement of both higher than average temperature and light, the mechanisms involved in bleaching are not well understood this project will test three hypotheses. 1. Bleaching in nature is caused by high temperature stress coupled with high energy blue light (and possibly UV-A between 380-400nm). Preliminary evidence shows that while high temperature alone will induce bleaching, natural light exposure during high temperature treatment exacerbates the effect by lowering the temperature threshold and time to bleaching at a given temperature. this study will determine which component of light is responsible for this effect and the mechanisms of action. Early theories on bleaching had light playing a major role, but experimental evidence has not yet supported this contention. Potentially harmful chemical alterations associated with high energy wavelengths of blue light (and possibly some near-blue wavelengths of UV-A, that are not adsorbed by UV-protecting pigments found in corals) are not only consistent with field observations of bleaching, but are also supported by both laboratory and field-based preliminary experiments. 2. The mechanisms of temperature-light induced bleaching involves the irreversible dissociation of the chlorophyll-protein associations in the chloroplast. The harmful effects of high temperatures and light on algae include the irreversible separation or inactivation of the chlorophyll-protein complexes associated with reaction centers in the chloroplast. Electron transport activity and eventually carbon fixation decrease markedly. 3. High light and temperatures cause decreases in "protective" pigments which absorb ultraviolet light. The role of different wavelengths of light in conjunction with high temperature in determining concentrations of UV-screening pigments will be determined as well as their relationship with photosynthetic rates. These hypotheses will be tested using cultured and freshly isolated zooxanthellae, and intact hosts both in the laboratory and in field-based experiments.

漂白，共生甲藻的损失）=“虫黄藻” 它们的色素，珊瑚礁和其他 无脊椎动物已成为热带海洋中一个世界性问题 生态系统，一些研究人员将其与全球变暖联系起来。 的 漂白的结果具有潜在的破坏性环境， 生态和经济影响在加勒比，印度太平洋， 其他热带海域。 虽然有一些实验性的 工作表现出参与高于平均温度 和光，漂白的机制并不好 据了解，该项目将测试三个假设。 1. 自然界中的漂白是由高温应力引起的 与高能量蓝光（以及可能的UV-A）耦合， 380-400nm）。 初步证据显示， 温度本身会导致漂白，自然光 高温处理期间的暴露加剧了 通过降低温度阈值和时间， 在给定的温度下漂白。 本研究将确定 光的哪一部分是造成这种效应的原因， 行动机制。 早期的漂白理论 光起着主要作用，但实验证据并没有 但支持这一论点。 潜在有害化学品 与高能量波长的蓝光有关的变化 光（可能还有一些近蓝色波长的UV-A， 不会被珊瑚中的紫外线保护色素吸收） 不仅与现场观察到的白化现象相一致， 但也得到了实验室和实地的支持， 初步实验。 2. 温光致漂白的机制包括： 叶绿素蛋白的不可逆解离 叶绿体中的联系。 高血压的有害影响 温度和光照对藻类的影响包括 叶绿素蛋白的分离或失活 与叶绿体中的反应中心有关的复合物。 电子传递活性和最终的碳固定 明显下降。 3. 强光和高温会导致“保护性” 吸收紫外线的颜料。 的作用 不同波长的光与高强度的 确定紫外线屏蔽浓度的温度 颜料将被确定，以及他们的关系， 光合速率 这些假设将使用培养的和新鲜分离的 虫黄藻，和完整的主机都在实验室和 实地实验。