Highlights

• Comprehensive review explores how marine microorganisms influence rare earth element distribution and concentration in deep-sea environments.
• Western Pacific sediments contain up to 8000 µg/g rare earth elements, with microbial processes playing a critical role in their cycling and enrichment.
• Current research suggests potential for biotechnological deep-sea extraction, though commercial viability remains theoretical.

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A comprehensive review by Dr. Shun Liu and Dr. Yinan Deng from the MNR Key Laboratory of Marine Mineral Resources (Guangzhou Marine Geological Survey) published in the Journal of Marine Science and Engineering (July 31, 2025) offers one of the most complete assessments to date of how rare earth elements and yttrium (REY) cycle, concentrate, and potentially become mineable in deep-sea environments—with a special focus on the emerging role of marine microorganisms.

The MNR Key Laboratory of Marine Mineral Resources is a research facility affiliated with the Ministry of Natural Resources (MNR) of China, specifically focused on the study of mineral resources found in the ocean. These laboratories are involved in research related to the formation, exploration, and potential utilization of marine mineral resources.

The Study

The study highlights that deep-sea sediments, especially in the Western Pacific, can contain up to 8000 µg/g REY, rivaling or exceeding high-grade terrestrial deposits. While riverine and hydrothermal sources contribute REY to seawater, biological processes—including microbial biosorption, bioaccumulation, and bioleaching—are now recognized as key agents in REY cycling and sediment enrichment.

Importantly, REY-hosting phases such as biogenic apatite and clay minerals are formed and transformed in part through microbial mediation. A limited number of marine bacterial strains, including Sulfitobacter sp. and Leisingera methylohalidivorans, have shown the capacity to enrich or transport specific REY (e.g., Ce, Yb, Nd). However, fewer than six marine strains with proven REY absorption capability have been identified to date.

Core Findings

• Microbial processes influence REY distribution, transformation, and sequestration in marine sediments.
• Western Pacific sediments host the richest marine REY concentrations; four key deep-sea metallogenic belts have been mapped.
• Redox-sensitive REY, like Ce, exhibit unique spatial behaviors due to biological and geochemical cycling.
• Genetically engineered strains have shown promise for bioleaching on land—but marine applications lag behind.

Limitations

• The commercial viability of deep-sea microbial REY extraction remains theoretical. No pilot-scale trials or techno-economic assessments yet exist.
• Most current microbial data are derived from terrestrial strains or lab models (E. coli, B. subtilis, S. cerevisiae), not native marine extremophiles.
• There is a critical data gap on REY concentrations in marine pore water and on microbe-specific gene pathways involved in REY processing.

Outlook for Investors

Marine REY resources may one day diversify global supply—but the microbial tools needed to extract them remain in the Petri dish. Still, as terrestrial REY faces social and environmental constraints, biotechnological deep-sea extraction could emerge as a cleaner, scalable solution.

For now, this remains a scientific frontier—not a shovel-ready resource. But for investors watching the edge of innovation, this study marks a clear step toward biologically mediated mining of marine rare earths.

Liu, S., & Deng, Y. (2025). Marine Rare Earth Elements: Distribution Patterns, Enrichment Mechanisms and Microbial Interactions. Journal of Marine Science and Engineering, 13(8), 1471. https://doi.org/10.3390/jmse13081471 (opens in a new tab)

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