Polymetallic nodules primary resource
Naturally occurring marine iron-manganese oxide and hydroxide concretions, commonly occurring on abyssal sediments and containing variable nickel, copper, cobalt and other constituents. This resource identity denotes the nodules, not a pure mineral species, constituent element, processing residue or defined traded metal grade. It is distinguished from rock-surface ferromanganese crusts and the terrestrial mixed manganese ore curated separately. Collection, drying and grinding do not make this geological feed a secondary resource. No constituent criticality designation is inherited.
Microbial & Biochemical Mechanisms (3)
Metal mobilization from nodules in heterotrophic enrichment cultures
bioleaching
Microbial
A laboratory enrichment-culture experiment reported metal mobilization from ground Clarion-Clipperton Zone nodules. It supports culture-associated leachate measurements under the reported conditions. The design does not isolate a microbial increment over matched sterile chemical leaching, establish a particular taxon or molecular cause, or demonstrate a commercially recovered product.
Experimental Context & Analytical Limits:
The approximately 2 kg source sample was collected by trawl in 2014 from the IOM H22 exploration block, sample 3521-1-TR1, at 4265–4291 m depth. Nodules were dried at room temperature and bowl-milled to 0.1–1 mm for leaching. Living mixed heterotrophic cultures were enriched from natural Fe/Mn-weathering mud; collection sites were withheld as proprietary. The 16S amplicon profile describes the starting mud, not experimentally isolated causal strains or a verified final enrichment composition, so no taxon identifier is assigned. Methods 2.3 describes serial enrichment and an MD medium containing 4 g/L citric acid and sucrose, with enrichment variants at 10 or 20 g/L sucrose. Methods 2.4 uses 0.25, 2.5, 25 or 50 g nodules, 240 mL medium plus 10 mL inoculum (nominal 0.1, 1, 10 or 20% w/v), sealed butyl-stoppered bottles, 38 +/- 0.5 degrees C and nominal pH 5.5 +/- 0.5; observed pH varies outside this interval. Five leachate collections with 150 mL replacement are described. The exact final carbon concentration and timing are not fully consistent across Methods, Results and diagrams. Bottle 5 is a separately formulated tap-water/sucrose condition, not a demonstrated sterile control. A bottle being sealed does not itself quantify dissolved oxygen. Analytical repeat measurements are described, but independent biological replication and uncertainty for leachate series are not adequately resolved.
The approximately 2 kg source sample was collected by trawl in 2014 from the IOM H22 exploration block, sample 3521-1-TR1, at 4265–4291 m depth. Nodules were dried at room temperature and bowl-milled to 0.1–1 mm for leaching. Living mixed heterotrophic cultures were enriched from natural Fe/Mn-weathering mud; collection sites were withheld as proprietary. The 16S amplicon profile describes the starting mud, not experimentally isolated causal strains or a verified final enrichment composition, so no taxon identifier is assigned. Methods 2.3 describes serial enrichment and an MD medium containing 4 g/L citric acid and sucrose, with enrichment variants at 10 or 20 g/L sucrose. Methods 2.4 uses 0.25, 2.5, 25 or 50 g nodules, 240 mL medium plus 10 mL inoculum (nominal 0.1, 1, 10 or 20% w/v), sealed butyl-stoppered bottles, 38 +/- 0.5 degrees C and nominal pH 5.5 +/- 0.5; observed pH varies outside this interval. Five leachate collections with 150 mL replacement are described. The exact final carbon concentration and timing are not fully consistent across Methods, Results and diagrams. Bottle 5 is a separately formulated tap-water/sucrose condition, not a demonstrated sterile control. A bottle being sealed does not itself quantify dissolved oxygen. Analytical repeat measurements are described, but independent biological replication and uncertainty for leachate series are not adequately resolved.
Curated Evidence Points:
Support
Source:
styriakova2022
Methods 2.1, Tables 2 and 4, and Figure 1 establish the actual heterogeneous nodule substrate and origin. The input sample has 26.75 wt% Mn, 4.95% Fe, 1.11% Ni, 1.28% Cu and 0.18% Co by portable XRF. These are sample-specific concentrations, not universal grades or pure-mineral composition.
Support
Source:
styriakova2022
Results 3.3 and Figures 2A and 5 report 2120 mg/L Mn in the fourth leachate collection of the nominal 10% w/v run (sample 3). This is a reported leachate concentration, not a recovery percentage, isolated mass or demonstrated dissolved Mn(II) speciation. Methods 2.1 describes portable XRF for solid and liquid analyses and ICP-OES confirmation of the solid sample-3 residue; it does not establish ICP-MS or a filtered dissolved-ion assay for this leachate.
Partial
Source:
styriakova2022
Methods 2.2–2.4 and Results 3.1–3.3 do not provide a matched uninoculated or killed-cell MD-medium comparator for the final leaching runs. Added citric acid and varying pH confound a microbial increment. Proposed direct Mn reduction, attachment-driven organic-acid production, individual Lactobacillus roles and selective adaptation are not separately demonstrated by the community profile or leachate measurements.
Partial
Source:
styriakova2022
Figure 3 and Discussion 4 show lower fractional metal extraction at higher pulp density, despite the larger sample-3 Mn concentration. Results 3.3 says all sample-3 metal recoveries fell below 20%, whereas Figure 3 and Discussion 4 give approximately 22% Ni; no blanket below-20% claim is adopted. The percentages derived from washed solid concentrations (Table 4) differ from leachate-based extraction, and the paper also reports a 13.3% solid mass decrease. Concentration depletion and changing residue mass are not interchangeable with a closed metal mass balance; those percentages are not curated as verified recovery yields.
Partial
Source:
styriakova2022
Methods 2.4 describes five transfers/collections, and Figure 5 provides numerical leachate values only for collections 1–5. Its combined box for collections 6–25 provides no measured concentration series. The proposed approximately 25 medium changes for complete extraction therefore do not establish an observed quantitative endpoint. The precipitation boxes in Figures 4–5 do not document isolated-product mass, composition or purity.
Partial
Source:
styriakova2022
The experiment remains laboratory-scale. Discussion 4 explicitly calls for semi-operational verification and economic assessment. The cited industrial BIOX pulp-density limit concerns a different gold-ore process, and does not establish industrial operation of this nodule culture. Environmental superiority is not demonstrated by these flask results.
Local growth and metal partitioning in Baltic nodule microcosms
biomineralization
Microbial
Natural microbial-community microcosms containing Baltic discoidal and spheroidal nodules showed local surface growth and changes in filtered solution metal concentrations. These observations are consistent with mineral accumulation under laboratory incubation, but poisoned controls do not independently establish a purely microbial increment or a metal-recovery process.
Experimental Context & Analytical Limits:
Majamäki et al. (2025) studied material collected in May–June 2022 from the Gulf of Finland. This mechanism covers the discoidal and spheroidal arms (sites 2 and 3; reported water depths 30 and 42 m), not the flat crust morphotype used as a separate comparison. Three to four natural nodules per bottle were rinsed with 0.22 µm-filtered seawater and placed in 125 mL artificial brackish seawater (salinity 4.7) in 250 mL bottles. Native living communities were retained; no isolated causal strain or taxon identifier is assigned. Rubber-sealed bottles were incubated in darkness at 3.5 degrees C and 100 rpm for 12 weeks. Separate destructive sampling bottles represented the initial 2–3-day timepoint and final timepoint: three biotic bottles and one 15 mM sodium-azide-treated comparator per morphotype and timepoint. Additional biotic bottles held small concretion pieces on glass rods for repeated CT scans and glass slides for microscopy. The artificial water initially had pH 6.9; Table 2 shows varying, near-neutral bottle pH rather than a fixed pH control. Solution samples were 0.2 µm-filtered, acidified and measured by ICP-MS. Full primary methods and figures were inspected; the linked supplementary DOCX could not be acquired, so its exact composition and source concentration cells are not independently verified or imported.
Majamäki et al. (2025) studied material collected in May–June 2022 from the Gulf of Finland. This mechanism covers the discoidal and spheroidal arms (sites 2 and 3; reported water depths 30 and 42 m), not the flat crust morphotype used as a separate comparison. Three to four natural nodules per bottle were rinsed with 0.22 µm-filtered seawater and placed in 125 mL artificial brackish seawater (salinity 4.7) in 250 mL bottles. Native living communities were retained; no isolated causal strain or taxon identifier is assigned. Rubber-sealed bottles were incubated in darkness at 3.5 degrees C and 100 rpm for 12 weeks. Separate destructive sampling bottles represented the initial 2–3-day timepoint and final timepoint: three biotic bottles and one 15 mM sodium-azide-treated comparator per morphotype and timepoint. Additional biotic bottles held small concretion pieces on glass rods for repeated CT scans and glass slides for microscopy. The artificial water initially had pH 6.9; Table 2 shows varying, near-neutral bottle pH rather than a fixed pH control. Solution samples were 0.2 µm-filtered, acidified and measured by ICP-MS. Full primary methods and figures were inspected; the linked supplementary DOCX could not be acquired, so its exact composition and source concentration cells are not independently verified or imported.
Curated Evidence Points:
Support
Source:
majamaki2025
Methods 2.1–2.4, Table 1 and Results 3.3/Figure 5 identify actual natural nodule substrate and the CT comparison. In the spheroidal specimen, three selected points on a roughly 200 µm-wide surface patch increased by 4.2, 5.2 and 6.2 µm over 12 weeks. These are local thickness measurements, not three biological replicate nodules, whole-nodule growth, an observed annual rate or recovered-metal mass. The frequently quoted approximately 10 µm maximum belongs to the separate flat-crust arm.
Support
Source:
majamaki2025
Results 3.4 and Figure 7b–c report lower mean Mn, Fe, Co, Ni, V, Zn and Mo concentrations after 12 weeks in the biotic discoidal and spheroidal microcosms. The azide comparators generally increased, but Fe decreased at both sites and V and Zn also decreased at site 2. The source reports substantial biotic variability and omits standard-deviation bars from its relative-change panels. These qualitative trends are distinct from a verified concentration-cell import or closed mass balance.
Partial
Source:
majamaki2025
Methods 2.2 and Discussion 4 leave one poisoned comparator per arm, possible residual microbial activity and possible azide effects on methane solubility. CT growth bottles have no reported matched poisoned CT series. Figure 6 SEM/EDS observations of O/Fe/Mn-bearing grains on a site-3 glass slide do not resolve crystalline phase or new precipitation uniquely: Discussion 4 acknowledges detached concretion fragments could reattach to the slide. Solution depletion likewise does not identify all receiving compartments or prove isolated product recovery.
Partial
Source:
majamaki2025
Discussion 4 proposes microbial oxidation and methanotrophy, but the metal data and headspace methane change do not identify a causal taxon, enzyme, metal oxidation state or electron-transfer pathway. Density/porosity-based volumes and annualized growth rates are calculations, not directly measured product yields. The experiment establishes no pilot or industrial deployment.
Metal partitioning between solution and bottle deposits in Baltic nodule microcosms
biomineralization
Microbial
A separate 2023-sampling microcosm experiment reported condition- and morphotype-dependent metal redistribution in natural Baltic nodules with their native communities. Lower solution concentrations relative to an azide comparator are not equivalent to net removal from the starting solution, and bottle-wall deposits are a separate receiving compartment from the nodules.
Experimental Context & Analytical Limits:
Majamäki et al. (2026) revisited Gulf of Finland sites and incubated natural discoidal and spheroidal nodules; the flat-crust arm is contextual only here. Three to four rinsed nodules were placed in 130 mL artificial brackish seawater (salinity 4.7) in 250 mL rubber-sealed bottles. Fe and Mn inputs were increased 30-fold relative to the earlier formulation, without importing unverified supplementary absolute concentrations. Separate initial (one day after sampling) and 15-week bottles comprised three biotic bottles and one 50 mM sodium-azide-treated comparator per morphotype and timepoint. Incubation was dark, 3.5 degrees C, 100 rpm. Table 2 gives mean pH 6.4 to 7.0 for discoidal biotic bottles and 6.3 to 7.1 for spheroidal biotic bottles; corresponding comparator values were 7.1 to 7.3 and 6.9 to 7.1. Starting nodule loads differed between independently sacrificed timepoints, particularly the discoidal arm (reported means 24.0 versus 17.8 g), so these are not before/after masses of the same nodules. Filtered solution and an acid wash of emptied, rinsed bottle walls were measured separately by ICP-MS. Native mixed communities were assessed with DNA/RNA sequencing; no isolated strain or taxon-specific causality is asserted. Main text and relevant figures were inspected, but supplementary raw concentration tables remain inaccessible.
Majamäki et al. (2026) revisited Gulf of Finland sites and incubated natural discoidal and spheroidal nodules; the flat-crust arm is contextual only here. Three to four rinsed nodules were placed in 130 mL artificial brackish seawater (salinity 4.7) in 250 mL rubber-sealed bottles. Fe and Mn inputs were increased 30-fold relative to the earlier formulation, without importing unverified supplementary absolute concentrations. Separate initial (one day after sampling) and 15-week bottles comprised three biotic bottles and one 50 mM sodium-azide-treated comparator per morphotype and timepoint. Incubation was dark, 3.5 degrees C, 100 rpm. Table 2 gives mean pH 6.4 to 7.0 for discoidal biotic bottles and 6.3 to 7.1 for spheroidal biotic bottles; corresponding comparator values were 7.1 to 7.3 and 6.9 to 7.1. Starting nodule loads differed between independently sacrificed timepoints, particularly the discoidal arm (reported means 24.0 versus 17.8 g), so these are not before/after masses of the same nodules. Filtered solution and an acid wash of emptied, rinsed bottle walls were measured separately by ICP-MS. Native mixed communities were assessed with DNA/RNA sequencing; no isolated strain or taxon-specific causality is asserted. Main text and relevant figures were inspected, but supplementary raw concentration tables remain inaccessible.
Curated Evidence Points:
Support
Source:
majamaki2026
Methods 2.1–2.3, Results 3.2–3.3 and Figure 5b–c distinguish this 15-week experiment from the 2022-sampling 12-week study. Both nodule arms show decreasing biotic solution Mn and increasing Fe over time. Many endpoint metal concentrations are lower than in the poisoned comparator even when the biotic concentration increased from its own initial value. This is conditional partitioning, not universal net metal capture.
Support
Source:
majamaki2026
Results 3.3 and Figures 6–7 document a separate bottle-wall-associated fraction obtained by acid washing. Spheroidal biotic bottles had a higher mean Mn concentration in this wash than their comparator, whereas discoidal bottles showed the opposite Mn pattern. Both biotic and comparator bottles accumulated material. REY patterns differ between solution and acid-wash fractions; solution depletion cannot all be assigned to nodule growth or to an isolated saleable product.
Partial
Source:
majamaki2026
Results 3.3 and Discussion 4.1 explicitly limit statistical strength because each comparison has one azide control and three variable biotic bottles. Azide can alter chemical/redox conditions; the study reports excessive N2O in poisoned controls and excludes those values from its main biotic N2O figure. Changed pH, unequal nodule loading and control chemistry prevent an unqualified microbial enhancement claim. This later experiment uses different metal inputs, duration and azide concentration and is not a replication at identical conditions.
Partial
Source:
majamaki2026
Methods 2.3 describes 5 mL acid plus three 5 mL rinses but then states a final 10 mL solution, leaving a volume inconsistency. No recovered metal mass, fraction-specific yield or complete mass balance is derived here. The main figures normalize some values and label them with concentration units; no normalized plot is treated as an original concentration cell. Supplementary numeric tables and exact formulation await verification.
Partial
Source:
majamaki2026
Methods 2.4–2.6, Figures 11–13 and Discussion 4.1–4.2 support community associations, not a demonstrated metal-transforming role for an individual taxon. The 2026 article also reanalyses community samples from the earlier 2022 experiment, which are not independent new microcosms. The authors explicitly cannot determine whether communities shape morphology/geochemistry or respond to them. No enzyme-specific mechanism, new pure mineral phase, recovered-metal grade or industrial operation is established.
Sources & References
-
usgs2025: U.S. Geological Survey (2025). U.S. Geological Survey Global Seabed Mineral Resources. Fact Sheet 2025–3017, version 1.1, April 2025; page 2, Table 1 distinguishes nodules on abyssal sediments from rock-surface ferromanganese crusts. Constituent asterisks refer to the U.S. 2022 list, not a criticality designation for these resource identities.
https://pubs.usgs.gov/fs/2025/3017/fs20253017.pdf (accessed 2026-10-11) -
styriakova2022: Štyriaková, Štyriaková, Šuba, Baláž and Abramowski (2022). Bioleaching Test of Polymetallic Nodule Samples from the IOM Exploration Area. Minerals 12(11):1373. DOI 10.3390/min12111373; full 14-page primary paper inspected, especially Methods 2.1–2.4, Results 3.1–3.3, Discussion 4, Tables 2–4 and Figures 2–5.
https://doi.org/10.3390/min12111373 (accessed 2026-10-11) -
majamaki2025: Majamäki et al. (2025). Microbially Enhanced Growth and Metal Capture by Ferromanganese Concretions in a Laboratory Experiment. Geobiology 23(1):e70010. DOI 10.1111/gbi.70010; published online 2 February 2025. Full 15-page primary paper, Methods 2.1–2.4, Tables 1–2, Results 3.3–3.4 and Figures 5–7 inspected. Supplementary DOCX was not acquired; no supplementary concentration cells are imported.
https://doi.org/10.1111/gbi.70010 (accessed 2026-10-11) -
majamaki2026: Majamäki et al. (2026). Different Ferromanganese Concretion Morphologies Host Distinct Microbial Communities and Metal Accumulation Patterns in the Baltic Sea. Environmental Microbiology 28(7):e70390. DOI 10.1111/1462-2920.70390; published online 23 July 2026. Full 27-page primary paper and Europe PMC full-text XML inspected, especially Methods 2.1–2.6, Results 3.2–3.3, Figures 5–7 and 11–13, and Discussion 4.1–4.2. Supplementary raw tables were not acquired.
https://doi.org/10.1111/1462-2920.70390 (accessed 2026-10-11)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-11T12:15:01.805194+00:00 |
codex (GPT-6; codex) | CREATE | Created marine nodule resource identity and qualified laboratory mixed-culture evidence, retaining control, carbon-formulation, analytical, mass-balance and scale limitations. |
2026-10-11T13:15:15.851639+00:00 |
codex (GPT-6; codex) | EDIT | Added separately scoped Baltic nodule microcosm growth and partitioning evidence from two experiments, preserving azide-control, receiving-compartment, replication, formula and supplementary-access limitations; did not create a locality-only resource duplicate. |
Record source: data/records/polymetallic-nodules.yaml