Abstract
In 2017, the New South Wales (NSW) Office of Environment and Heritage (OEH) initiated a state-wide mapping program, SeaBed NSW, which systematically acquires high-resolution (2–5 m cell size) multibeam echosounder (MBES) and marine LiDAR data along more than 2000 km of the subtropical-to-temperate southeast Australian continental shelf. This program considerably expands upon existing efforts by OEH to date, which have mapped approximately 15% of NSW waters with these technologies. The delivery of high volumes of new data, together with the vast repository of existing data, highlights the need for a standardised, automated approach to classify seabed data. Here we present a methodological approach with new procedures to semi-automate the classification of high-resolution bathymetry and intensity (backscatter and reflectivity) data into a suite of data products including classifications of seabed morphology (landforms) and composition (substrates, habitats, geomorphology). These methodologies are applied to two case study areas representing newer (Wollongong, NSW) and older (South Solitary Islands, NSW) MBES datasets to assess the transferability of classification techniques across input data of varied quality. The suite of seabed classifications produced by this study provide fundamental baseline data on seabed shape, complexity, and composition which will inform regional risk assessments and provide insights into biodiversity and geodiversity.
Highlights
Understanding the form and nature of the seabed is a critical first step in managing coastal and marine ecosystems [1,2]
The methodologies and techniques presented here, developed from a 5-m multibeam echosounder (MBES) digital elevation models (DEMs), can be applied to the statewide marine LiDAR program currently being undertaken in New South Wales (NSW), as part of SeaBed NSW, and integrated with new and existing MBES data to produce a seamless classification for nearshore and offshore seabed environments
This study presents a methodological framework and new techniques for classifying seabed morphology and composition on continental shelf environments, exemplified with case study areas along the subtropical-temperate passive continental shelf of NSW, Australia
Summary
Understanding the form and nature of the seabed is a critical first step in managing coastal and marine ecosystems [1,2]. Bathymetry data, intensity data, and their derivatives can be integrated with ground-truthing data to predict distributions of biota and substrates across broad spatial scales and create continuous surfaces of predicted species of sediment distributions and categorical maps of geomorphic features and biotopes [1,6]. Such maps are integral for marine spatial planning [7,8], fisheries resource assessments [9], marine biodiversity assessments [10], and hazard risk assessments [11,12]. Global coverage of bathymetry data is available through derived altimetry methods, the resolution of these grids (30 arc-second grid cells, ~1 km at the equator) are considered too coarse for most regional or local management applications and it is estimated that less than 18% of the earth’s surface is mapped with echosounding equipment [14,15]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
