Coral Reef Primary Production and Calcification: Quantitative Analysis of Sensitivity to Environmental Forcing using a Control Volume Approach

由于大气中二氧化碳含量增加的影响，海洋目前正在经历变暖和酸化，预计到2100年海洋表面pH值将下降至少0.3个pH单位。珊瑚礁尤其容易受到这两种因素的影响。在这项研究中，斯坦福大学的科学家将专注于酸化的影响，结合工程、物理海洋学和海洋生物地球化学领域的新方法和方法，对整个物理环境和健康珊瑚礁的不同群落的碳流进行定量了解。在位于大堡礁的Heron岛海洋站的四个野外季节中，他们将通过确定沿三维控制体积（CV）边界的水柱无机碳系统特性，首次同时和现场测量大型完整珊瑚礁带上的净群落生产/呼吸和净群落钙化/溶解。拟议研究的总体目标是：1)通过直接，原位测量碳系统通量，量化珊瑚礁与开放海洋之间以及不同珊瑚礁环境内的能量流动；2)描述初级生产和钙化的日、季节和年际变化及其对流动状态和碳酸盐饱和状态的依赖；3)对珊瑚礁系统对全球气候和碳循环持续扰动的相互作用进行预测评估。为了实现这些目标，pi将安装一系列电流计、波浪计和热敏电阻，以确定在10厘米的空间尺度和秒的时间尺度下控制体积内的水动力状态。然后，利用雷诺输运定理和水柱碳化学数据，他们将计算通过四个CV面和表面边界的净通量，从而确定底栖生物群落与上覆水体之间的净碳通量。更广泛的影响包括学生指导、国际合作和推广工作。斯坦福大学在澳大利亚有一个海外学习项目，将允许3 - 5名本科生参加这个项目，作为他们的荣誉论文。来自印度尼西亚、巴布亚新几内亚或其他西太平洋国家等发展中国家的科学家也将获得对沿海海洋进行地球化学监测的经验。pi还将与博物馆专家合作，开发一个关于海洋酸化和珊瑚礁的博物馆展览。

The oceans are currently experiencing both warming and acidification due to the effects of increasing atmospheric CO2 levels, with surface ocean pH expected to drop by at least 0.3 pH units by the year 2100. Coral reefs are especially vulnerable to both factors. In this research, scientists from Stanford University will focus on the effects of acidification, combining novel methods and approaches from the fields of engineering, physical oceanography, and marine biogeochemistry to develop a quantitative understanding of the flow of carbon throughout the physical environment and varied communities of a healthy coral reef. During four field seasons at Heron Island Marine Station, located on the Great Barrier Reef, they will make the first simultaneous and in situ measurements of Net Community Production/Respiration and Net Community Calcification/Dissolution on a large intact coral reef tract by determining water column inorganic carbon system properties along the boundaries of a 3-dimensional control volume (CV). The overall goals of the proposed research are to: 1) Quantify how energy flows between a coral reef and the open ocean, and within different reef environments, by direct, in situ measurements of carbon system fluxes; 2) Describe diurnal, seasonal, and interannual variability in primary production and calcification and their dependency on flow regime and carbonate saturation state; and 3) Develop predictive assessments regarding the interactive response of coral reef systems to ongoing perturbations of global climate and the carbon cycle. To achieve these goals, the PIs will install an array of current meters, wave gauges, and thermistors to determine the hydrodynamic regime within the control volume at a spatial scale of 10 cm and time scale of seconds. Then, using the Reynolds Transport Theorem and water column carbon chemistry data, they will calculate net fluxes through each of the four CV faces and the surface boundary, and thereby determine net carbon fluxes between the benthic community and the overlying water.Broader impacts includes student mentoring, international collaboration, and outreach efforts. Stanford University conducts an overseas study program in Australia that will permit 3 to 5 undergraduate students to participate in this project for their honors thesis. Scientists from developing nations, such as Indonesia, Papua New Guinea, or other western Pacific nations, will also gain experience in geochemical monitoring of the coastal ocean. The PIs will also work with museum experts to develop a museum exhibit on ocean acidification and coral reefs.