Underwater visual monitoring methods are used broadly to evaluate coral reef conditions in the natural environment, but quantitative measurements of the coral holobiont has been largely restricted to photophysiological assessment of the endosymbionts. An underwater respirometer has been designed to make routine, diver-operated, non-invasive measurements at coral surfaces, but the realistic in situ accuracy and precision capabilities of this device has not been critically assessed; an essential step if these measurements are to be useful for quantifying spatial and seasonal patterns of coral metabolism. We developed specific protocols for this system to survey shallow coral colonies and detect metabolic profiles (respiration, photosynthesis, and biocalcification), diel cycles (day and night), and photosynthesis-irradiance curves. Analysis of data from in situ and laboratory-controlled conditions showed good replication among coral colonies and high precision measurements of temperature, oxygen and pH fluxes over 15-min incubation times without noticeable detrimental effects on coral health. Moreover, marked differences were observed in coral calcification rates between estuarine-influenced and coastal marine conditions, despite the absence of significant differences in visual appearance or other health indicators, revealing the system’s potential for early detection of marginally adverse conditions for coral metabolism. Its ease of operation and rapid quantification of the physiological status of the corals make this respirometer well suited for use by reef scientists, monitoring agencies, and stakeholders in biogenic reefs conservation efforts. Moreover, the high spatial and temporal resolution of these underwater respirometer data will have the potential to discriminate the effects of local stressors on coral health from those generated by broader changes associated with climate drivers.

中文翻译：

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潜水员便携式呼吸测量系统，用于对珊瑚代谢健康和钙化率进行原位短期测量

水下视觉监测方法被广泛用于评估自然环境中的珊瑚礁状况，但对珊瑚全生物的定量测量在很大程度上仅限于对内共生体的光生理学评估。水下呼吸计的设计目的是在珊瑚表面进行常规的、潜水员操作的、非侵入性的测量，但该设备的真实原位精度和精度能力尚未得到严格评估；如果这些测量值有助于量化珊瑚代谢的空间和季节性模式，这是必不可少的一步。我们为此系统开发了特定的协议，以调查浅层珊瑚群落并检测代谢特征（呼吸、光合作用和生物钙化）、昼夜循环（白天和黑夜）和光合作用 - 辐照度曲线。对来自原位和实验室控制条件的数据的分析表明，珊瑚群之间的复制良好，并且在 15 分钟的孵化时间内对温度、氧气和 pH 值通量进行了高精度测量，而对珊瑚健康没有明显的不利影响。此外，尽管视觉外观或其他健康指标没有显着差异，但在受河口影响的和沿海海洋条件之间观察到珊瑚钙化率存在显着差异，这表明该系统有可能及早发现珊瑚代谢的轻微不利条件。其易于操作和对珊瑚生理状态的快速量化使这种呼吸计非常适合珊瑚礁科学家、监测机构和生物珊瑚礁保护工作的利益相关者使用。而且，