Add Alaska Tundra Permafrost Iron-Redox Community from orphan cache

[realmarcin]

Summary

Curate a new community YAML (`CommunityMech:000262`) from PMID:37996661 (Patel et al. 2024 ISME Communications, "Genomic evidence that microbial carbon degradation is dominated by iron redox metabolism in thawing permafrost") — an orphan cache that did not have any community citing it.

System: northern Alaska wet sedge tundra organic soils from active-layer (0-50 cm), transition-zone (50-70 cm), and permafrost (70+ cm) depths, incubated at 4 °C for 30 days under reducing conditions to mimic extended thaw.

Members captured:

• Heterotrophic Fe(III)-reducing Rhodoferax sp. (NCBITaxon:28065)
• Chemoautotrophic Fe(II)-oxidizing Gallionella sp. (NCBITaxon:96)
• Co-resident wet sedge tundra methanogens whose CH4-metabolism gene abundance decreased

The combined iron-cycling pair increased 3–5 orders of magnitude in absolute abundance and accounted for 65% of community abundance after extended thaw.

Interactions captured:

1. Fe(III) reduction coupled to acetate/benzoate oxidation (SYNTROPHY)
2. Competitive suppression of acetoclastic methanogenesis by Fe(III) reduction (COMPETITION)
3. Iron redox cycling between Rhodoferax and Gallionella (CROSS_FEEDING, PARTIAL — abstract doesn't explicitly trace Fe²⁺/Fe³⁺ exchange between specific cells)

Plus two environmental factors: anaerobic thaw incubation and the depth gradient.

Test plan

• `just validate kb/communities/Alaska_Tundra_Permafrost_Iron_Redox_Community.yaml` — no schema issues
• `just validate-references kb/communities/Alaska_Tundra_Permafrost_Iron_Redox_Community.yaml` — passes (all snippets are verbatim substrings of the cached PubMed abstract)
• `just validate-references-all` still reports 39 errors (no new errors introduced)

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Adds a new curated CommunityMech community record (CommunityMech:000262) describing an Alaska wet sedge tundra permafrost-thaw microbial community and its iron redox–linked carbon cycling, based on PMID:37996661.

Changes:

• Introduces a new community YAML with environment description and perturbation context (depth gradient + anaerobic thaw incubation).
• Captures three taxa (Rhodoferax, Gallionella, and a methanogen guild) plus three ecological interactions (Fe(III) reduction/organic acid oxidation, competition with methanogenesis, and an iron redox cycle hypothesis).
• Adds evidence blocks citing PMID:37996661 across taxa, interactions, and environmental factors.

Comments suppressed due to low confidence (6)

kb/communities/Alaska_Tundra_Permafrost_Iron_Redox_Community.yaml:69

• This SUPPORT snippet does not appear verbatim in references_cache/PMID_37996661.md (the abstract text is line-broken and includes different spacing/characters). Please update the snippet to match an exact substring of the cached abstract so it remains a verbatim supporting quote.

    snippet: chemoautotrophic Fe(II)-oxidizing Gallionella sp., increased by 3-5
      orders of magnitude in absolute abundance within the transition-zone and permafrost
      microbiomes, accounting for 65% of community abundance
    explanation: Establishes Gallionella as the chemoautotrophic Fe(II)-oxidizer
      partner and quantifies the combined dominance of the Fe-cycling pair.

kb/communities/Alaska_Tundra_Permafrost_Iron_Redox_Community.yaml:87

• This SUPPORT snippet is not a verbatim substring of references_cache/PMID_37996661.md (it removes the line break between “decreased” and “following” and omits surrounding words). Please copy an exact excerpt from the cached abstract to keep evidence quotes verbatim.

    snippet: Gene abundance for CH4 metabolism decreased following extended thaw,
      suggesting dissimilatory Fe(III) reduction suppresses acetoclastic methanogenesis
    explanation: Supports a co-resident methanogenic guild whose activity is
      suppressed by Fe(III) reduction during anaerobic thaw.

kb/communities/Alaska_Tundra_Permafrost_Iron_Redox_Community.yaml:139

• This SUPPORT snippet is not an exact substring of the cached abstract (it omits the leading “We also found that …” and collapses line breaks). Please update to a verbatim excerpt from references_cache/PMID_37996661.md to satisfy the project’s evidence/snippet contract.

    snippet: the abundance of genes for Fe(III) reduction (e.g., MtrE) and Fe(II)
      oxidation (e.g., Cyc1) increased concurrently with genes for benzoate degradation
      and pyruvate metabolism, in which pyruvate is used to generate acetate that
      can be oxidized, along with benzoate, to CO2 when coupled with Fe(III) reduction
    explanation: Directly supports Fe(III) reduction coupled to acetate and benzoate
      oxidation as the dominant carbon-cycling pathway.

kb/communities/Alaska_Tundra_Permafrost_Iron_Redox_Community.yaml:177

• This SUPPORT snippet does not match the cached abstract verbatim (it omits “suggesting” / surrounding context). Please replace with an exact substring from references_cache/PMID_37996661.md for verbatim evidence support.

    snippet: dissimilatory Fe(III) reduction suppresses acetoclastic methanogenesis
      under reducing conditions
    explanation: Directly states the competitive-suppression mechanism between
      Fe(III) reduction and acetoclastic methanogenesis in post-thaw permafrost.

kb/communities/Alaska_Tundra_Permafrost_Iron_Redox_Community.yaml:216

• Even though this is marked PARTIAL, the snippet should still be a verbatim excerpt from the cached abstract. Right now it omits leading context (“We also found that …”) and collapses the reference’s line breaks; please update it to an exact substring from references_cache/PMID_37996661.md.

    supports: PARTIAL
    evidence_source: COMPUTATIONAL
    snippet: the abundance of genes for Fe(III) reduction (e.g., MtrE) and Fe(II)
      oxidation (e.g., Cyc1) increased concurrently
    explanation: Supports the simultaneous activation of Fe(III)-reduction and
      Fe(II)-oxidation gene abundance, consistent with an iron redox cycle linking
      the two dominant taxa. Partial because the abstract does not explicitly trace
      the Fe(II)/Fe(III) exchange between specific cells.

kb/communities/Alaska_Tundra_Permafrost_Iron_Redox_Community.yaml:242

• This SUPPORT snippet appears to be a paraphrase (missing “we determined …”) rather than a verbatim substring of references_cache/PMID_37996661.md. Please replace it with an exact excerpt from the cached abstract so evidence text remains verbatim.

    supports: SUPPORT
    evidence_source: IN_VIVO
    snippet: relative and absolute changes in microbiome composition and functional
      gene abundance during thaw incubations of wet sedge tundra collected from northern
      Alaska, USA

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