Geomorphology
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A high-resolution multibeam echosounder (MBES) dataset covering over 279,000 km2 was acquired in the southeastern Indian Ocean to assist the search for Malaysia Airlines Flight 370 (MH370) that disappeared on 8 March 2014. The data provided an essential geospatial framework for the search and is the first large-scale coverage of MBES data in this region. Here we report on geomorphic analyses of the new MBES data, including a comparison with the Global Seafloor Geomorphic Features Map (GSFM) that is based on coarser resolution satellite altimetry data, and the insights the new data provide into geological processes that have formed and are currently shaping this remote deepsea area. Our comparison between the new MBES bathymetric model and the latest global topographic/bathymetric model (SRTM15_plus) reveals that 62% of the satellite-derived data points for the study area are comparable with MBES measurements within the estimated vertical uncertainty of the SRTM15_plus model (± 100 m). However, > 38% of the SRTM15_plus depth estimates disagree with the MBES data by > 100 m, in places by up to 1900 m. The new MBES data show that abyssal plains and basins in the study area are significantly more rugged than their representation in the GSFM, with a 20% increase in the extent of hills and mountains. The new model also reveals four times more seamounts than presented in the GSFM, suggesting more of these features than previously estimated for the broader region. This is important considering the ecological significance of high-relief structures on the seabed, such as hosting high levels of biodiversity. Analyses of the new data also enabled sea knolls, fans, valleys, canyons, troughs, and holes to be identified, doubling the number of discrete features mapped. Importantly, mapping the study area using MBES data improves our understanding of the geological evolution of the region and reveals a range of modern sedimentary processes. For example, a large series of ridges extending over approximately 20% of the mapped area, in places capped by sea knolls, highlight the preserved seafloor spreading fabric and provide valuable insights into Southeast Indian Ridge seafloor spreading processes, especially volcanism. Rifting is also recorded along the Broken Ridge – Diamantina Escarpment, with rift blocks and well-bedded sedimentary bedrock outcrops discernible down to 2400 m water depth. Modern ocean floor sedimentary processes are documented by sediment mass transport features, especially along the northern margin of Broken Ridge, and in pockmarks (the finest-scale features mapped), which are numerous south of Diamantina Trench and appear to record gas and/or fluid discharge from underlying marine sediments. The new MBES data highlight the complexity of the search area and serve to demonstrate how little we know about the vast areas of the ocean that have not been mapped with MBES. The availability of high-resolution and accurate maps of the ocean floor can clearly provide new insights into the Earth's geological evolution, modern ocean floor processes, and the location of sites that are likely to have relatively high biodiversity. <b>Citation:</b> Kim Picard, Brendan P. Brooke, Peter T. Harris, Paulus J.W. Siwabessy, Millard F. Coffin, Maggie Tran, Michele Spinoccia, Jonathan Weales, Miles Macmillan-Lawler, Jonah Sullivan, Malaysia Airlines flight MH370 search data reveal geomorphology and seafloor processes in the remote southeast Indian Ocean, <i>Marine Geology</i>, Volume 395, 2018, Pages 301-319, ISSN 0025-3227, https://doi.org/10.1016/j.margeo.2017.10.014.
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The service contains the Australian Coastal Geomorphology Smartline, used to support a national coastal risk assessment. The 'Smartline' is a representation of the geomorphic features located within 500m of the shoreline, denoted by the high water mark. The service includes geomorphology themes and stability classes.
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This OGC Web Feature Service (WFS) contains geospatial seabed morphology and geomorphology information for Cairns Seamount within the Coral Sea Marine Park and are intended for use by marine park managers, regulators, the general public and other stakeholders. This web service uses the data product published in McNeil et al. (2023); eCat Record 147998.
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This ESRI map (web) service contains geospatial seabed morphology and geomorphology information for the Beagle Marine Park (South-east Marine Parks Network) and is intended for use by marine park managers, regulators and other stakeholders. This web service uses the data product published in Nanson et al. (2023); eCat Record 147976.
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The service contains the Australian Coastal Geomorphology Smartline, used to support a national coastal risk assessment. The 'Smartline' is a representation of the geomorphic features located within 500m of the shoreline, denoted by the high water mark. The service includes geomorphology themes and stability classes.
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This flythrough video highlights deep and mesophotic seabed environments within the Coral Sea Marine Park, offshore northeastern Australia. The mesophotic zone, commonly referred to as the ‘twilight zone’ represents the depth range below the brightly lit shallow waters down to the maximum depth that sunlight can penetrate for photosynthesis to occur (~ 30 to 150 meters beneath the sea surface). The featured Malay and North Flinders Reefs represent mid-ocean platform reefs and Cairns Seamount hosts a thriving coral reef community atop what is likely an extinct volcanic cone. These locations represent a range of benthic communities, which vary with depth and substrate type. Soft-sediments (sands, muds and oozes) dominate the deep seafloor, with evidence of water currents that produce bedforms showing active sediment transport at these depths. The walls and flanks of the platform reefs are very steep, with evidence of slope failure where rocky head walls have collapsed and deposited large blocks and boulders on the seafloor, which provide important habitat for sessile and mobile invertebrates including soft corals and sponges as well as cryptic octopus. Typical mesophotic habitats included vast Halimeda algal meadows and rhodolith beds interspersed with soft corals and sponges on soft-sediment. Hard substrates were typically colonised by plate and encrusting hard Scleractinian corals (e.g. Leptoseris and Montipora species), sponges and ascidians. Many large black corals (Antipatharia) and gorgonians (Octocorallia) also featured, with several black coral and carnivorous sponge observations representing new species. The reef community atop Cairns Seamount was highly diverse and included many demersal and pelagic fish species. A high abundance and diversity of gelatinous zooplankton were observed in the deep waters between reefs in the Coral Sea, with several new range extensions recorded. Bathymetry data and seafloor imagery for this flythrough were collected on RV Falkor, owned and operated by the Schmidt Ocean Institute (SOI), during surveys FK200830 and FK200902 in August and October 2020. These surveys were led by Geoscience Australia and James Cook University. Collaborative research partners included the Japan Agency for Marine-Earth Science and Technology, The University of Tokyo, Queensland University of Technology, Queensland Museum, The University of Sydney, University of Tasmania and the University of Wollongong.
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This OGC Web Feature Service (WFS) contains geospatial seabed morphology and geomorphology information for the Beagle Marine Park (South-east Marine Parks Network) and is intended for use by marine park managers, regulators and other stakeholders. This web service uses the data product published in Nanson et al. (2023); eCat Record 147976.
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This OGC Web Feature Service (WFS) contains geospatial seabed morphology and geomorphology information for Flinders Reefs within the Coral Sea Marine Park and are intended for use by marine park managers, regulators, the general public and other stakeholders. This web service uses the data product published in McNeil et al. (2023); eCat Record 147998.
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This ESRI map (web) service contains geospatial seabed morphology and geomorphology information for Cairns Seamount within the Coral Sea Marine Park and are intended for use by marine park managers, regulators, the general public and other stakeholders. This web service uses the data product published in McNeil et al. (2023); eCat Record 147998.
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This ESRI map (web) service contains geospatial seabed morphology and geomorphology information for Flinders Reefs within the Coral Sea Marine Park and are intended for use by marine park managers, regulators, the general public and other stakeholders. This web service uses the data product published in McNeil et al. (2023); eCat Record 147998.