Shelf-invading low-oxygen waters control Cenozoic organic carbon burial rates
陸棚に侵入する低酸素水が新生代の有機炭素埋没率を制御する (AI 翻訳)
Rosalind E. M. Rickaby, Thomas J. Wood, Zunli Lu, Christian J. Bjerrum
🤖 gxceed AI 要約
日本語
本論文は、新生代を通じた有機炭素埋没率（f_org）の制御要因を、炭素同位体比、リン蓄積、I/Ca比などの高解像度データを用いて再評価した。海水準の変動が陸棚域の堆積面積を変化させ、リン利用可能性・一次生産・酸素極小帯（OMZ）の発達を介してf_orgに影響を与えることを示した。特に、OMZが陸棚に侵入する中間的海水準時に有機炭素埋没が促進される「スイートスポット」が存在し、地球の気候安定化に寄与したと提案している。
English
This paper reassesses controls on the global proportion of carbon buried as organic carbon (f_org) over the Cenozoic using high-resolution carbon isotope records, phosphorus accumulation, and I/Ca data. It demonstrates that sea-level changes regulate the areal extent of shelf sedimentation, influencing phosphate availability, primary productivity, and oxygen minimum zone (OMZ) development. The authors propose a self-limiting 'sweet spot' at intermediate sea levels where OMZs impinge on shelf sediments, enhancing organic carbon burial and stabilizing atmospheric CO₂ and O₂ over Earth history.
Unofficial AI-generated summary based on the public title and abstract. Not an official translation.
📝 gxceed 編集解説 — Why this matters
日本のGX文脈において
本研究成果は、地球史における炭素循環の長期的フィードバック機構を理解する上で重要だが、日本のGX政策（SSBJ開示、2050年カーボンニュートラル）への直接的な示唆は限定的。ただし、気候感度や炭素除去の自然ポテンシャル評価の基礎として、気候モデルやカーボンバジェット研究に間接的に寄与しうる。
In the global GX context
This paleoclimate study provides fundamental insights into long-term carbon cycle feedbacks, but its direct relevance to global GX frameworks (TCFD, ISSB, CSRD) is low. It may indirectly inform climate sensitivity estimates and natural carbon removal potentials considered in IPCC assessments and net-zero pathways.
👥 読者別の含意
🔬研究者:This paper offers a refined understanding of how sea level and ocean oxygenation interact to control organic carbon burial over geologic timescales, useful for Earth system modelers and paleoclimate scientists.
📄 Abstract（原文）
The thermostatic mechanisms of Earth’s persistent habitability remain unresolved. High-resolution Cenozoic C isotope records, P accumulation, and coarse-fraction I/Ca allow recalculation and assessment of controls on the global proportion of total carbon buried as organic carbon ( f org ), a regulator of atmospheric CO 2 and O 2 . f org was suppressed during the Eocene hothouse, coincident with an oxygenated water column and low water-column phosphate. With decreased sea level, the area for efficient organic carbon and phosphate sedimentary burial diminished, leading increasingly to greater water-column phosphate, higher primary productivity, and emergent water column deoxygenation. The sea-level influence on the areal extent of high sedimentation in shelf regions acts as a control on phosphate availability for new production, respiratory demand, and ocean oxygenation, as proposed by hypsographic models [C. J. Bjerrum, J. Bendtsen, J. J. F. Legarth, Geochem. Geophys. Geosys. 7 , 1–24 (2006)]. During intermediate sea-level highs of the Neogene, pulses of enhanced organic carbon burial prevailed for multimillion years, in response to the redox recycling of phosphate when oxygen minimum zones with O 2 < 90 µmol/kg were present. We propose the existence of a self-limiting intermediate sea-level sweet spot with peak C org burial due to redox recycling of phosphate, whereby oxygen minimum zones (OMZ) with O 2 < 90 µmol/kg impinge on the most C org rich continental shelf sediments. Such a sweet spot has narrowed over Earth history due to deepening OMZs, stabilizing both atmospheric O 2 and CO 2 . Continental marine inundation controls on phosphate availability, and the sedimentary carbon flux, provide a positive-feedback and rectifier to perturbations during inception of the icehouse world.
🔗 Provenance — このレコードを発見したソース
- openalex https://doi.org/10.1073/pnas.2526409123first seen 2026-06-24 04:47:31
🔔 こうした論文の新着を逃したくない方は キーワードアラート に登録（無料・3キーワードまで）。
gxceed は公開メタデータに基づく研究支援データセットです。要約・翻訳・解説は AI 支援で生成されています。 最終的な解釈・検証は利用者が原典資料に基づいて行うことを前提とします。