Leigh Marine Laboratory, University of Auckland, P.O. Box 349, Warkworth 0941, New Zealand.
Environ Sci Technol. 2010 Dec 1;44(23):8821-8. doi: 10.1021/es1012752. Epub 2010 Oct 29.
Depth and topography directly and indirectly influence most ocean environmental conditions, including light penetration and photosynthesis, sedimentation, current movements and stratification, and thus temperature and oxygen gradients. These parameters are thus likely to influence species distribution patterns and productivity in the oceans. They may be considered the foundation for any standardized classification of ocean ecosystems and important correlates of metrics of biodiversity (e.g., species richness and composition, fisheries). While statistics on ocean depth and topography are often quoted, how they were derived is rarely cited, and unless calculated using the same spatial resolution the resulting statistics will not be strictly comparable. We provide such statistics using the best available resolution (1-min) global bathymetry, and open source digital maps of the world's seas and oceans and countries' Exclusive Economic Zones, using a standardized methodology. We created a terrain map and calculated sea surface and seabed area, volume, and mean, standard deviation, maximum, and minimum, of both depth and slope. All the source data and our database are freely available online. We found that although the ocean is flat, and up to 71% of the area has a < 1 degree slope. It had over 1 million approximately circular features that may be seamounts or sea-hills as well as prominent mountain ranges or ridges. However, currently available global data significantly underestimate seabed slopes. The 1-min data set used here predicts there are 68,669 seamounts compared to the 30,314 previously predicted using the same method but lower spatial resolution data. The ocean volume exceeds 1.3 billion km(3) (or 1.3 sextillion liters), and sea surface and seabed areas over 354 million km(2). We propose the coefficient of variation of slope as an index of topographic heterogeneity. Future studies may improve on this database, for example by using a more detailed bathymetry, and in situ measured data. The database could be used to classify ocean features, such as abyssal plains, ridges, and slopes, and thus provide the basis for a standards based classification of ocean topography.
深度和地形直接或间接地影响着大多数海洋环境条件，包括光穿透和光合作用、沉积、海流和分层，以及因此的温度和氧气梯度。这些参数可能会影响海洋物种的分布模式和生产力。它们可以被认为是海洋生态系统标准化分类的基础，也是生物多样性指标（如物种丰富度和组成、渔业）的重要相关因素。虽然经常引用海洋深度和地形的统计数据，但很少引用它们的来源，除非使用相同的空间分辨率进行计算，否则得到的统计数据将不完全可比。我们使用最好的可用分辨率（1 分钟）全球测深图以及世界海洋和海洋国家专属经济区的开源数字地图，按照标准化方法提供这些统计数据。我们创建了地形地图，并计算了海面和海底的面积、体积以及深度和坡度的平均值、标准差、最大值和最小值。所有的原始数据和我们的数据库都可以在网上免费获得。我们发现，尽管海洋是平坦的，超过 71%的区域坡度小于 1 度，但它有超过 100 万个近似圆形的特征，这些特征可能是海山或海底山，也可能是显著的山脉或山脊。然而，目前可用的全球数据大大低估了海底坡度。这里使用的 1 分钟数据集预测有 68669 个海山，而之前使用相同方法但空间分辨率较低的数据预测有 30314 个海山。海洋体积超过 13 亿立方公里（或 13 万亿升），海面和海底面积超过 3540 万平方公里。我们提出用坡度的变异系数作为地形异质性的指标。未来的研究可以改进这个数据库，例如使用更详细的测深图和现场测量数据。这个数据库可以用来对海洋特征进行分类，例如深海平原、山脊和斜坡，从而为海洋地形的标准化分类提供基础。
