National Coral Reef Monitoring Program: Benthic Cover Derived from Analysis of Benthic Images Collected for Climate Stations across the Pacific Remote Island Areas from 2015-01-26 to 2015-04-27 (NCEI Accession 0159152)

The data described here result from benthic photo-quadrat surveys conducted along transects at climate stations and permanent sites identified by the Ocean and Climate Change team across the Pacific Remote Island Areas since 2014. Benthic habitat imagery were quantitatively analyzed using Coral Point Count with Excel extensions (CPCe; Kohler and Gill, 2006) software from 2010-2014 and a web-based annotation tool called CoralNet (Beijbom et al. 2016) from 2015 to present. In general, images are analyzed to produce three functional group levels of benthic cover: Tier 1 (e.g., hard coral, soft coral, macroalgae, turf algae, etc.), Tier 2 (e.g., Hard Coral = massive, branching, foliose, encrusting, etc.; Macroalgae = upright macroalgae, encrusting macroalgae, bluegreen macroalgae, and Halimeda, etc.), and Tier 3 (e.g., Hard Coral = Astreopora sp, Favia sp, Pocillopora, etc.; Macroalgae = Caulerpa sp, Dictyosphaeria sp, Padina sp, etc.).

Climate stations are 3-4 sites per island that were selected in a stratified random fashion to be roughly equally spaced around the island, along the 15 m contour, on hard bottom, and at least 1 km away from a river mouth or embayment. Once selected we assess multiple features of the coral reef environment including in-situ temperature (STR), seawater carbonate, net carbonate accretion (CAU), bioerosion (BMU), and cryptobiota diversity (ARMS).

本文所述数据集源自2014年以来，太平洋偏远岛屿区域海洋与气候变化团队在其划定的气候监测站及永久样地中沿样带开展的底栖照相样方调查。2010至2014年，研究团队采用带Excel扩展模块的珊瑚点计数软件（Coral Point Count with Excel extensions，简称CPCe；Kohler与Gill，2006）对底栖生境影像进行定量分析；2015年至今，则改用名为CoralNet的在线注释工具（Beijbom等，2016）开展相关分析。通常情况下，影像分析会生成三个功能组层级的底栖覆盖度数据：一级分类（如硬珊瑚、软珊瑚、大型藻类、藻席等）、二级分类（如硬珊瑚可分为团块状、分枝状、叶状、壳状等类群；大型藻类可分为直立型大型藻类、壳状大型藻类、蓝绿藻大型藻类以及仙掌藻属（Halimeda）等类群）、三级分类（如硬珊瑚包含星珊瑚属（Astreopora sp.）、蜂巢珊瑚属（Favia sp.）、杯形珊瑚属（Pocillopora）等类群；大型藻类包含蕨藻属（Caulerpa sp.）、网胰藻属（Dictyosphaeria sp.）、团扇藻属（Padina sp.）等类群）。

气候监测站在每个岛屿设置3至4个样地，采用分层随机抽样法选取，设置标准为：沿岛屿周边大致等距分布、位于15米等深线处、硬质底质环境，且距离河口或海湾至少1公里。样地选定后，研究人员会对珊瑚礁环境的多项特征开展评估，包括原位温度（STR）、海水碳酸盐体系、净碳酸盐沉积量（CAU）、生物侵蚀量（BMU）以及隐栖生物多样性（ARMS）。