1. Coral growth rates vary significantly with environmental conditions and are thus important indicators of coral health and reef carbonate production. Despite the importance of this metric, data are sparse for most coral genera and species globally, including for many key reef‐building species. Traditional methods to obtain growth rates, such as coral coring or staining with Alizarin are destructive and only work for a limited number of species and morphological growth forms.
2. Emerging approaches, using underwater photogrammetry to create digital models of coral colonies, are providing novel and non‐invasive ways to explore colony‐scale growth patterns and to address existing knowledge gaps. We developed an easy‐to‐follow workflow to construct three‐dimensional (3D) models from overlapping photographs and to measure linear, radial and vertical extension rates of branching, massive and encrusting corals after aligning colony models from subsequent years.
3. The method presented here was applied to measure extension rates for 46 colonies of nine coral species in the remote Chagos Archipelago, Indian Ocean. Proposed image acquisition and software settings produced 3D models of consistently high resolution and detail (precision ≤ 0.2 mm) and variability in growth measurements was small despite manual alignment, clipping and ruler placement (SD ≤ 0.9 mm). Measured extension rates for the Chagos Archipelago are similar to published rates in the Indo‐Pacific where comparable data are available, and provide the first published rates for several species. For encrusting corals, the results emphasize the importance of differentiating between radial and vertical growth.
4. Photogrammetry and 3D model comparisons provide a fast, easy, inexpensive and non‐invasive method to quantify coral growth rates for a range of species and morphological growth forms. The simplicity of the presented workflow encourages its repeatability and permits non‐specialists to learn photogrammetry with the goal of obtaining linear coral growth rates. Coral growth rates are essential metrics to quantify functional consequences of ongoing community changes on coral reefs and expanded datasets for key coral taxa will aid predictions of geographic variations in coral reef response to increasing global stressors.

中文翻译：

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使用摄影测量和3D模型比较来快速，轻松，无创地定量珊瑚生长速率的方法

1. 珊瑚的生长速率随环境条件而变化很大，因此是珊瑚健康和碳酸盐碳酸盐生产的重要指标。尽管该指标很重要，但全球大多数珊瑚属和物种的数据稀少，包括许多重要的造礁珊瑚物种。传统的获取生长速率的方法（例如珊瑚取心或用茜素染色）具有破坏性，仅适用于有限数量的物种和形态生长形式。
2. 新兴的方法，使用水下摄影测量法创建珊瑚群落的数字模型，正在提供新颖且非侵入性的方法来探索群落规模的生长模式并解决现有的知识空白。我们开发了易于遵循的工作流程，以根据重叠的照片构建三维（3D）模型，并在调整了后续年份的菌落模型之后，测量了分支珊瑚，块状珊瑚和结壳珊瑚的线性，径向和垂直延伸率。
3. 本文介绍的方法用于测量印度洋偏远查戈斯群岛中9种珊瑚的46个殖民地的扩展率。提出的图像采集和软件的设置产生的3D模型中生长测量始终如一的高的分辨率和细节（精密≤/0.2毫米）和变性的小尽管手动对准，削波和直尺放置（SD  ≤0.9毫米）。查戈斯群岛测得的延展率与印度太平洋地区已公布的可比较数据相似，并提供了几种物种的首次公布率。对于包壳珊瑚，结果强调区分径向和垂直生长的重要性。
4. 摄影测量和3D模型比较提供了一种快速，简便，廉价且无创的方法，可以量化一系列物种和形态生长形式的珊瑚生长速度。所呈现工作流程的简单性鼓励了其可重复性，并允许非专业人士学习摄影测量法，以期获得线性珊瑚生长速率。珊瑚生长速率是量化社区不断变化对珊瑚礁的功能后果的重要指标，而关键珊瑚生物群的扩展数据集将有助于预测珊瑚礁对全球压力源不断增加的反应的地理变化。