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

珊瑚礁正受到全球环境压力的困扰，包括海面温度上升和海洋酸化。但我们仍然不太了解珊瑚对这些压力的反应。我们需要了解压力反应，如果我们要有效地规划保护工作，以拯救我们不断变化的地球上的珊瑚，包括海洋保护区的位置和设计。珊瑚是群体生物，由重复单位（珊瑚虫）组成，所有这些单位都连接在一个群体中。每个息肉都有一个中央胃血管腔，直接参与许多生理功能，如消化和气体交换。科学家早就知道有两种类型的殖民地？蓝图珊瑚种类：一种是群体中所有个体息肉的胃血管腔通过一个一直开放的管道系统连接（即，开放式），另一种是仅相邻息肉的胃血管腔通过一个微小的管道系统连接（即，开放式），该管道系统仅在息肉扩张时才开放。因此，珊瑚虫物种有可能在殖民地的所有珊瑚虫之间持续分享营养，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。在不受限制的物种的空间和时间的循环范围是有限的。 这项研究将是第一次系统地研究珊瑚和非珊瑚对环境压力的反应。最初的实验将使用温度压力，因为全球变暖通过更频繁的珊瑚漂白事件导致珊瑚死亡率增加。研究人员已经制定了一个数学模型，该模型以电气网络（网络上的每个节点都是一个单一的息肉）为模式，预测溶解氧和pH值（影响光合作用，呼吸和钙化的酸度测量）在珊瑚群落内部和周围的变化。生理模型的预测将被测试为从两个息肉到数千个大小不等的菌落。了解微小的年轻殖民地如何应对热应力是很重要的，因为健康的珊瑚礁的持续增长需要年轻的殖民地繁荣和成长，这可能不会发生在一定的阈值温度以上。大型殖民地的表现是重要的理解，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，其中一些是从人类医学中借鉴来的。研究人员将测量个体息肉的胃血管系统内部以及殖民地表面的一些变量，以量化正常和压力温度下的生理功能。他们还将从珊瑚虫中提取组织样本，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，该模型应可用于预测几乎所有珊瑚物种对压力的生理反应。该项目将涉及本科生和研究生，以及博士后学者，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教育工作，包括课堂参观，公开演示和课程计划，将在屡获殊荣的VIMS Bridge网站上提供。在研究过程中也有可能开发出对从事海洋生物研究的生理学家有用的新技术。

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.