Seamounts and raised seabed features of the Australian margin (NESP MaC 2.3)

Seamounts, elevated seabed features, and bathymetric highs constitute ecologically significant habitats for various marine species, often associated with unique ecosystems and heightened biodiversity. In Australia, the absence of a comprehensive and spatially accurate inventory of these underwater structures has been a notable gap. Existing broad-scale modelling efforts, including the Parks Australia Natural Values Ecosystems (NVE) map (https://seamapaustralia.org/map/#af207808-481a-4648-93d3-4011f2689461), have predominantly relied on coarse, global datasets. These datasets, characterized by low resolution, often fail to incorporate recent bathymetric data, leading to the omission or incorrect identification of features. This work aimed to address these limitations by developing an improved dataset of raised seabed features, specifically designed to enhance broad-scale modelling efforts like those used in the NVE mapping, and in support of the objectives of NESP Marine and Coastal Hub Project 2.3 (https://www.nespmarinecoastal.edu.au/project/2-3/).

Seamount features were extracted from a range of data sources (see 'lineage' section of this record) for the area surrounding the Australian continental margin. These were cross-referenced with GEBCO's 2023 global terrain model (15 arc-second interval grid) and any obviously erroneous features removed. This dataset includes all features located inside the Australian Exclusive Economic Zone (EEZ). Rather than cropping exclusively to this boundary, those features falling outside the Aus EEZ but in the approximate vicinity were also retained for context

Existing feature boundaries were redigitised for areas in which more recent high-resolution bathymetry was available, utilising the 'Bathymetry of Australian Marine Parks (2024)' compilation dataset and individual survey datasets available through the AusSeabed data portal (https://portal.ga.gov.au/persona/marine). Where available, fine-scale geomorphic mapping in which seamounts and pinnacles had been classified were extracted and merged with the larger-scale features. If fine-scale mapping disagreed with features classified in the broader-scale datasets, the finer-scale data was prioritised.

Where multiple features occurred immediately adjacent to each other, the digitised area represents the "footprint" of the features and as such, a single polygon may encompass multiple peaks. Where features could be uniquely identified (eg by a formal name/title), this attribute is included in the dataset.

This dataset will continue to be updated as more bathymetry data is collected, or until such time that a new authoritative seamounts dataset is released for the Australian margin.

海山（Seamounts）、隆起海底地貌（elevated seabed features）以及水深地形高地（bathymetric highs），是多种海洋物种的重要生态栖息地，通常与独特生态系统及更高水平的生物多样性密切相关。在澳大利亚，此类水下构造缺乏全面且空间精度达标的清查目录，这是一项显著的研究空白。
现有大规模建模工作——包括澳大利亚公园管理局自然价值生态系统（Natural Values Ecosystems, NVE）地图（链接：https://seamapaustralia.org/map/#af207808-481a-4648-93d3-4011f2689461）——主要依赖低分辨率的全球数据集。这类数据集分辨率较低，通常未能纳入最新水深地形数据，进而导致部分地貌特征被遗漏或识别错误。本研究旨在通过构建优化的隆起海底地貌数据集来弥补上述局限，该数据集专门用于改进NVE地图等大规模建模工作，同时支持NESP（国家环境科学计划，National Environmental Science Program）海洋与海岸枢纽项目2.3（链接：https://www.nespmarinecoastal.edu.au/project/2-3/）的目标实现。

本数据集针对澳大利亚大陆边缘周边海域，从多类数据源中提取海山地貌特征（详见本记录的“谱系（lineage）”章节）。随后将提取的特征与国际海洋水深测量委员会（General Bathymetric Chart of the Oceans, GEBCO）2023年全球地形模型（15角秒间隔网格）进行交叉比对，并移除所有明显存在错误的特征。本数据集涵盖澳大利亚专属经济区（Exclusive Economic Zone, EEZ）内的所有海山地貌特征。本数据集并未严格裁剪至该边界范围内，同时保留了澳大利亚专属经济区外但邻近区域的相关特征，以提供完整的背景信息。

针对拥有最新高分辨率水深地形数据的海域，本研究利用《澳大利亚海洋公园水深地形（2024）》整合数据集，以及通过AusSeabed数据门户（链接：https://portal.ga.gov.au/persona/marine）获取的各类勘测数据集，对原有地貌特征边界进行了重新数字化矢量化。若有可用的精细尺度地貌制图数据（其中已完成海山与尖峰地貌的分类），则将其提取并与大规模制图的特征进行融合。若精细尺度制图结果与大规模数据集的分类结果存在分歧，则优先采用精细尺度的数据。

当多个地貌特征彼此紧邻时，矢量化区域代表该类特征的“覆盖范围（footprint）”，因此单个多边形可能包含多个峰顶。若地貌特征可被唯一标识（例如通过正式名称/标题），则该属性信息将被纳入本数据集。

本数据集将持续更新，直至收集到更多水深地形数据，或针对澳大利亚大陆边缘发布新的权威海山数据集为止。