The utilization of first-order information about seafloor morphology, derived from multibeam sonar data, has become common in the investigation of deep-sea benthic habitats. When combined with complementary datasets, these data can be used to study deep-sea coral ecosystems and predict environments that are favorable for fish spawning, larval nurseries, and juvenile fish habitats. The identification and protection of these environments is critical where biodiversity is vulnerable or unique in order to rehabilitate or maintain ecological communities and encourage higher fecundity. In August of 2019, the expedition Deep Connections: Exploring Atlantic Canyons and Seamounts was conducted to explore understudied deep-sea environments aboard the NOAA Ship Okeanos Explorer off the coast of the United States and Canada (EX1905L1 and EX1905L2). This expedition included multibeam mapping and seafloor exploration with a Remotely Operated Vehicle (ROV). Observations from ROV dives include several fish species including multiple sightings of Atlantic halibut (Hippoglossus hippoglossus), which is considered endangered on the International Union for Conservation of Nature Red List of Threatened Species. Identifying and classifying the habitats where Atlantic halibut is observed would facilitate future endeavors of protection or rehabilitation. Spawning events are known to coincide with areas of increased seafloor slope associated with high energy systems such as canyons. Utilizing multibeam data included in the Global Multi-Resolution Topography (GMRT) Synthesis, we characterize canyons at the edges of George’s and Brown’s Banks based on morphology, roughness, and seafloor slope and aspect. We combine these data with observations of Atlantic halibut from ROV video to seek correlations that can be used to identify potential habitats. This information can be used to guide further exploration and characterization of the seafloor to better understand the spatial extent of Atlantic halibut habitat in the region.

The Global Multi-Resolution Topography (GMRT) Synthesis is an elevation model that includes curated deep-water multibeam bathymetry data at ~100 m resolution covering more than 9% of the ocean. GMRT is built with a scalable tiled raster architecture that efficiently stores and presents high-resolution elevation data nested within low resolution data. A set of tools are available for users to access the compilation through simple user interfaces (e.g. GMRT MapTool) and web services, while also providing full attribution and access to source swath files. The availability of raw/unprocessed multibeam sonar data in the National Centers for Environmental Information (NCEI) archive has increased dramatically over the last decade, but transforming these data into high-quality integrated products suitable for use by scientists and the public alike requires significant effort. The GMRT Team has built workflows and tools for data preparation and review that are optimized for cleaning and integrating sparse globally distributed multibeam data, enabling the addition of ~60-80 research cruises per year. Once raw swath data files are cleaned and corrected, they are gridded/tiled with the GMRT Tiling tools so they can be reviewed and quality controlled in the context of other data in the GMRT Synthesis. Working with processed swath files generated by the community, we have observed that this process frequently reveals issues that are overlooked during data processing. In order to accelerate the rate of data integration and leverage the data processing efforts of the community, GMRT Tiling tools are being adapted for distributed use. Ocean Exploration Trust is an initial partner in this effort, and all processed swath files from the 2017-2019 Nautilus field seasons were prepared with GMRT Tiling tools and reviewed by the OET team. This revealed problems in processed swath data files from several cruises that were addressed prior to submission to NCEI, thereby improving the quality of data in the archive. We are now working to include the GMRT Tiling tools into at-sea standard operating procedures of the Nautilus as a testbed for broader community distribution, to ensure consistent quality of processed multibeam data, and to accelerate the production of high-quality integrated data products including GMRT and Seabed 2030.