Underwater acoustic data is important for understanding the oceans and how sound affects the marine environment. To record underwater sounds produced by, for instance, marine mammals, waves, and ships, and to capture the complexity and interactions of the marine soundscape, hydrophones and other acoustic recording devices are used. These devices capture massive amounts of unstructured data, which is difficult to manage. In addition, sound propagation models produce gridded data that are often used to visualize the propagation of noise over time.
To improve discoverability, accessibility and reusability of underwater acoustic data we have developed and implemented a data discovery platform. This project consists of four major deliverables, which have been, or will be, released to the general public. These deliverables are:
- The development of a metadata standard to appropriately describe underwater acoustic data, while addressing the community’s needs (https://docs.meridian.cs.dal.ca/metadata/)
- The development and implementation of the technical backend (coming soon)
- A user-friendly information submission interface (https://discovery.meridian.cs.dal.ca/)
- A multi-layer search and discovery interface to ensure the data’s discoverability (http://discovery.meridian.cs.dal.ca/search, redesign planned).
Our metadata profile for underwater acoustic data is interoperable with many other profiles and conventions based on the ISO 19115 standard, such as the U.S. Integrated Ocean Observing System Metadata Convention for Passive Acoustic Recordings. The MERIDIAN metadata profile also incorporates the Darwin Core metadata standard for biological information, allowing easier integration with services such as the Ocean Biogeographic Information System (OBIS).
The initial release of the data discovery platform made use of GeoNetwork to manage and catalogue our metadata. This includes a MERIDIAN metadata profile plugin. The ElasticSearch integration of GeoNetwork was used to power our custom search and discovery interface. While GeoNetwork is widely used and supports many common types of metadata harvesting, its implementation does not fully meet our needs. This initial release is being replaced by a full redesign including a MongoDB document store, but the initial release is currently active and will continue to be accessible via our GitLab (https://gitlab.meridian.cs.dal.ca/Infrastructure/meridian-beta-catalog-service-public).
Rather than using GeoNetwork’s built-in submission interface, we have developed a custom submission interface to upload metadata records. This submission interface uses as much non-expert terminology as practicable as well as simple reusable HTML components in order to create a modular web form capable of reuse in multiple contexts.
We have also developed a customized user interface for searching and displaying metadata records to better reflect the requirements of the underwater acoustic community. The ElasticSearch (eventually MongoDB) back-end provides an API for querying record data, which is used to render search results and metadata records. Our service supports location-based searches, keyword-based searches, author searches, and searches by date. As it is populated by user-submitted records, it will allow researchers, data scientists, and other users to discover and access open data of relevance to marine acoustic research that are stored across Canada.