The deep sea –commonly accepted as the ocean realm below 200 meters- is the largest and one of the most diverse ecosystems on Earth. Our understanding of it is growing rapidly, especially with the recent interest in deep-seabed resources. While the deep-sea environment can be exceptionally harsh, with extreme pressure and no sunlight, recent studies have revealed that life is nonetheless abundant.
As exploration for deep-seabed minerals progresses in the international seabed area (the Area) and regulations for future exploitation of those minerals are being drafted, the taxonomic identification, classification and description of species that are found in areas potentially becoming open to exploitation, are essential to informing the development of adequate measures to protect deep-sea biodiversity and associated ecosystem services.
The need to strengthen the collective scientific knowledge of deep-sea biodiversity is highlighted in the International Seabed Authority (ISA)’s Strategic Plan and High-Level Action Plan for 2019-2023, as well as in its Action Plan in support of the United Nations Decade of Ocean Science for Sustainable Development, which identifies standardization of methodologies for deep-sea biodiversity assessment, including taxonomic identification and description in the Area, as one of its six strategic research priorities.
Building on the work undertaken by pioneer investors and exploration contractors over the last 40 years, ISA is working closely with contractors and taxonomists around the world to advance deep-sea taxonomy. Together, they strive to promote standardized methodologies; harness new technologies and create a global network of experts to support the development of a sound regulatory framework based on the best available data and information.
Areas Under Exploration, Habitats and Biodiversity
ISA has so far approved 31contracts to 22 to explore patches of the seabed in the Pacific, Indian and Atlantic Ocean for three types of mineral resources, which are associated with different types of habitats and, therefore, different biological communities. Polymetallic nodule fields are found in abyssal plains, cobalt-rich ferromanganese crusts are formed on seamounts, and polymetallic sulfides in mid-ocean ridge hydrothermal vent systems.
The contractors have been carrying out environmental surveys to characterize biological communities, from microbiota to megafauna, in their respective areas for many years. In some cases, for more than twenty years. This work has contributed greatly to improve the collective knowledge of deep-sea biodiversity in recent years. In the Clarion-Clipperton Zone, for example, thanks to this work, nearly 100 new organisms were formally described in a single year(2017-2018).
Challenges and Opportunities of Deep-Sea Taxonomy
The taxonomic work flow involves extensive and lengthy steps, from collection, preservation and archiving of biological samples, to identification and description of species, to archiving and sharing of taxonomic data. Advancing deep-sea taxonomy will require a heightened level of standardization of methods and protocols, increased funding, trained experts and collaboration among all institutions involved.
Collection, preservation and archiving of biological samples
Physical specimens are the prime samples for taxonomists. During environmental surveys, ISA contractors collect specimens in the water column and on/near the seabed and preserve them on board vessels. Methods of collection and preservation need to ensure the morphological and molecular integrity of samples. Once on shore, samples should be stored for the long term in curated biological collections, preferably public, at natural history museums for instance, for research and education purposes.