Alan J. Jamieson, Gaelen T. Giles, Heather A. Stewart
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引用次数: 0
Abstract
The hadal zone (water depths > 6000 m) are unlike the overlying shallower marine regions (bathyal and abyssal) as it does not follow a continuum from the continental shelves to abyssal plains, but rather exhibits a globally disjunct series of discrete deep-sea habitats confined within geomorphological features. From an ecological perspective, hadal communities are often endemic to individual or adjacent features and are partitioned and isolated by geomorphological structures. To examine the size, shape, depth and degree of isolation of features where hadal fauna inhabit, this study explores the broad seafloor geomorphology, and distinctly partitioned hadal areas, across the Southwest Pacific and East Indian oceans using global bathymetric datasets. This research revealed the area occupied by hadal depths to be 716,915 km2 of which 58% are accounted for by trenches, 37% in basins and troughs, and 5% fracture zones. The largest feature in terms of area > 6000 m depth is the Wharton Basin with 218,030 km2 spanning 376 discrete areas. The largest continuous hadal habitats were the Kermadec and Tonga trenches at 145,103 and 111,951 km2 respectively, whereas features such as the Java Trench comprise two hadal components partitioned by a bathymetric high. Conversely, no physical barrier exists between the New Britain and Bougainville trenches thus any literature pertaining to hadal species or habitats from these trenches can be merged. This study highlights that the hadal zone mainly comprises two main geomorphological features (trenches and basins) that differ in size, depth and complexity. Hadal basins cover vast, generally shallower areas, comparable to abyssal plains, whereas trenches, despite a lesser footprint, represent greater depth ranges and complexity. As such, sampling designs and interpretation of ecological data must differ and hadal basins likely play an increasingly important role in understanding ecological shifts from abyssal to hadal ecosystems.
期刊介绍:
Well-established international journal presenting marine geophysical experiments on the geology of continental margins, deep ocean basins and the global mid-ocean ridge system. The journal publishes the state-of-the-art in marine geophysical research including innovative geophysical data analysis, new deep sea floor imaging techniques and tools for measuring rock and sediment properties.
Marine Geophysical Research reaches a large and growing community of readers worldwide. Rooted on early international interests in researching the global mid-ocean ridge system, its focus has expanded to include studies of continental margin tectonics, sediment deposition processes and resulting geohazards as well as their structure and stratigraphic record. The editors of MGR predict a rising rate of advances and development in this sphere in coming years, reflecting the diversity and complexity of marine geological processes.