REEs exhibit unique physical, chemical, and light-emitting properties and are very much needed in developing and implementing clean energy technologies. Although relatively abundant in the Earth’s crust, economic REE deposits are rather rare. The REEs are divided into light and heavy. Rare earth elements (REEs) is the name for a group of 15 lanthanide elements however, we also include here the chemically similar elements yttrium and scandium in the designation REEs. A more efficient use of resources is needed along with the development of new green technologies to ensure that long-term global growth is environmentally sound. This growth will require increased food, energy, and raw materials, putting pressure on the environment. The world’s population is projected to grow from 7.8 × 10 9 in 2020 to 9.8 × 10 9 in 2050, according to a United Nations report. The world economy is predicted to grow at an average of just over 3 % per annum in the period 2014 to 2050 and nearly tripling by 2050. By protecting vulnerable areas, applying new technologies for deep-sea mineral exploration and mining, marine spatial planning, and a regulatory framework for minerals extraction, we may achieve sustainable management and use of our oceans. The development of a blue economy strategy needs a better knowledge of the environmental impacts. The global ocean is an immense source of food, energy, raw materials, clean water, and ecosystem services and suffers seriously by multiple stressors from anthropogenic sources. Furthermore, marine mining may cause conflicts with various stakeholders such as fisheries, communications cable owners, offshore wind farms, and tourism. Ecological impacts of rare earth element mining on deep-sea ecosystems are still poorly evaluated. The main concerns of deep-sea mining are related to its environmental impacts. Moreover, shallow-water resources, like placer deposits, represent another marine source for many critical minerals, metals, and gems.

In addition, zones for marine phosphorites exploration are located in Chatham Rise, offshore Baja California, and on the shelf off Namibia. Major areas with economic interest for seabed mineral exploration and mining are the following: nodules in the Penrhyn Basin-Cook Islands Exclusive Economic Zone (EEZ), the Clarion–Clipperton nodule Zone, Peru Basin nodules, and the Central Indian Ocean Basin seafloor massive sulfide deposits in the exclusive economic zones of Papua New Guinea, Japan, and New Zealand as well as the Mid-Atlantic Ridge and the three Indian Ocean spreading ridges cobalt-rich crusts in the Pacific Prime Crust Zone and the Canary Islands Seamounts and the Rio Grande Rise in the Atlantic Ocean and the rare earth element-rich deep-sea muds around Minamitorishima Island in the equatorial North Pacific. Marine mineral deposits with a great resource potential for transition, rare, and critical metals include mainly deep-sea mineral deposits, such as polymetallic sulfides, polymetallic nodules, cobalt-rich crusts, phosphorites, and rare earth element-rich muds. Because the demand for critical metals is increasing and land-based mineral deposits are being depleted, seafloor resources are seen as the next frontier for mineral exploration and extraction. The expected growth of the global economy and the projected rise in world population call for a greatly increased supply of materials critical for implementing clean technologies, such as rare earth elements (REEs) and other rare metals.

Deep blue marine