How does the gastrovascular system in perforate and imperforate corals affect physiological response to environmental stress?

有孔和无孔珊瑚的胃肠血管系统如何影响对环境压力的生理反应？

• 批准号: 1146056
• 负责人: Mark Patterson
• 金额: $ 55.28万
• 依托单位: College of William & Mary Virginia Institute of Marine Science
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2014-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1146056&HistoricalAwards=false
• 关键词: How; does; gastrovascular; system; perforate

Coral reefs are under siege from global environmental stresses including increased sea surface temperature and ocean acidification. But we still poorly understand how corals react to these stresses. We need to understand the stress response if we are to effectively plan conservation efforts to save corals on our changing planet, including the location and design of marine protected areas. Corals are colonial organisms, composed of repeating units (polyps) all connected in a colony. Each polyp has a central, gastrovascular cavity that is directly involved in many physiological functions, such as digestion and gas exchange. Scientists have known for a long time that there are two types of colony ?blueprints? for coral species: one where the gastrovascular cavities of all of the individual polyps in a colony are connected by a plumbing system that is open all the time (perforate), and another type (imperforate) in which the gastrovascular cavities of only adjacent polyps are connected by a tiny plumbing system that is only open when the polyps are expanded. Thus, perforate coral species have the potential to share nutrition continuously between all polyps in the colony because the internal plumbing connections function like a primitive circulatory system, with cilia driving flow inside these tiny pipes. The spatial and temporal extent of circulation in imperforate species is more limited. This research will be the first systematic examination of how perforate and imperforate corals respond to environmental stress. The initial experiments will use temperature stress because global warming is causing increasing coral mortality through more frequent coral bleaching events. The researchers have formulated a mathematical model patterned after an electrical network (where each node on the network is a single polyp) that predicts how dissolved oxygen and pH (a measure of acidity that affects photosynthesis, respiration, and calcification) will vary inside and around a coral colony. The predictions of the physiological model will be tested for colonies ranging in size from two polyps to thousands. Understanding how tiny young colonies react to thermal stress is important because continued growth of healthy reefs requires that juvenile colonies prosper and grow, which may not happen above certain threshold temperatures. The performance of large colonies is important to understand, as they produce a disproportionate share of coral larvae. The research will use sophisticated sensors and techniques, some of them borrowed from human medicine. The researchers will make measurements of a number of variables inside the gastrovascular system of individual polyps, and over the surface of the colony, to quantify physiological functions under normal and stressful temperatures. They will also take tissue samples from the polyps to measure heat shock proteins, protective compounds made by all life forms on Earth when under stress. This research will produce a tested general predictive model that should be usable to predict physiological response to stress in almost every coral species. This project will involve undergraduate and graduate students, and a postdoctoral scholar, some of whom are from groups underrepresented in science. There will also be significant K-12 educational efforts including classroom visits, public demonstrations, and lesson plans that will be available on the award-winning VIMS Bridge web site. There is also the possibility that new technology will be developed during the research that will be useful to physiologists who work with marine organisms.

珊瑚礁正受到全球环境压力的围困，包括海洋表面温度上升和海洋酸化。但我们仍然对珊瑚如何应对这些压力知之甚少。如果我们要有效地计划保护工作，以保护我们不断变化的星球上的珊瑚，包括海洋保护区的位置和设计，我们需要了解压力反应。珊瑚是群体生物体，由连接在一个群体中的重复单位(息肉)组成。每个息肉都有一个中央的胃血管腔，直接参与许多生理功能，如消化和气体交换。科学家们很早就知道有两种类型的殖民地？蓝图？对于珊瑚物种：一种是一个群体中所有单个息肉的胃血管腔由始终开放的管道系统连接(穿孔)，另一种类型是只有相邻息肉的胃血管腔由一个只有在息肉扩张时才开放的微小管道系统连接起来。因此，穿孔珊瑚物种有可能在群落中的所有息肉之间持续分享营养，因为内部管道连接的功能就像一个原始的循环系统，纤毛驱动这些微小管道内的流动。无孔物种的环流在空间和时间上的范围较为有限。这项研究将是第一次系统地研究穿孔和闭孔珊瑚如何应对环境压力。最初的实验将使用温度压力，因为全球变暖正在通过更频繁的珊瑚漂白事件导致珊瑚死亡增加。研究人员已经制定了一个数学模型，以电子网络(网络上的每个节点都是一个息肉)为模型，预测珊瑚群体内部和周围的溶解氧和pH(影响光合作用、呼吸作用和钙化的酸度指标)将如何变化。生理模型的预测将在大小从两个息肉到数千个的蜂群中进行测试。了解微小的年轻群体对温度压力的反应是很重要的，因为健康的珊瑚礁的持续生长需要年轻群体的繁荣和增长，而这可能不会发生在特定的阈值温度以上。理解大群体的表现很重要，因为它们产生了不成比例的珊瑚幼虫。这项研究将使用复杂的传感器和技术，其中一些是借鉴人类医学的。研究人员将对单个息肉的胃血管系统内和菌落表面的一些变量进行测量，以量化正常和紧张温度下的生理功能。他们还将从息肉中提取组织样本，以测量热休克蛋白，这是地球上所有生命形式在压力下产生的保护性化合物。这项研究将产生一个经过测试的通用预测模型，该模型应该可以用来预测几乎所有珊瑚物种对压力的生理反应。这个项目将涉及本科生和研究生，以及一名博士后学者，其中一些人来自科学界代表性不足的群体。还将有重要的K-12教育努力，包括课堂访问、公共演示和课程计划，这些将在获奖的VIMS Bridge网站上提供。也有可能在研究过程中开发出对研究海洋生物的生理学家有用的新技术。