Soil Carbon Stocks in Fijian Seagrass: Environmental Drivers, National Inventories, and Implications for Blue Carbon Accounting in Small Island Settings
フィジーの海草における土壌炭素ストック：環境要因、国家インベントリ、及び小島嶼環境におけるブルーカーボン会計への示唆 (AI 翻訳)
Joseph R. Crosswell, Wendy‐Jane Powell, Geoffrey Carlin, Christina Asanopoulos, Carrie Wentzel, Mitchell B. Lyons, Andrew D. L. Steven
🤖 gxceed AI 要約
日本語
フィジーの海草床における土壌炭素ストックを全国規模で初めて評価。135のコアサンプルから、有機炭素ストックは全球平均より2～12倍低く、Tier1のデフォルト値では過大評価となることを示した。空間的不均一性が変動の主因で、島嶼部の地形学的要因が炭素貯留に強く影響する。この結果は、小島嶼国におけるブルーカーボン会計の枠組みとして応用可能。
English
This study presents the first national-scale assessment of seagrass soil carbon stocks in Fiji, based on 135 sediment cores. Mean organic carbon stocks were 2–12 times lower than global averages, and Tier 1 defaults would overestimate stocks by an order of magnitude. Spatial heterogeneity at sub-island scales dominated variability, with geomorphic factors such as hydrodynamic setting being key controls. The findings highlight the need for island-specific carbon accounting frameworks.
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
日本ではブルーカーボン生態系（藻場・海草床）の炭素貯留量評価が進んでいるが、本論文は小島嶼国特有の地形効果を組み込んだTier 2推定手法を示しており、日本の沿岸域や離島におけるブルーカーボン評価の精度向上に参考となる。
In the global GX context
This paper provides a transferable Tier 2 carbon accounting framework for small island settings, emphasizing geomorphic controls on carbon stocks. It challenges the applicability of global defaults and supports national-level blue carbon inventories, aligning with IPCC guidelines and emerging carbon crediting mechanisms like the Paris Agreement's Article 6.
👥 読者別の含意
🔬研究者:Offers a robust methodology for national-scale blue carbon assessment in data-sparse regions, with insights on spatial heterogeneity drivers.
🏢実務担当者:Provides a practical framework for estimating seagrass carbon stocks in small island states, which can inform national greenhouse gas inventories and blue carbon projects.
🏛政策担当者:Highlights the risk of using global defaults for national carbon accounting in small islands, supporting the need for site-specific Tier 2 estimates under the IPCC guidelines.
📄 Abstract（原文）
Abstract Pacific island seagrass systems remain critically underrepresented in global blue carbon assessments despite their potential significance for climate mitigation. We present the first national‐scale assessment of seagrass soil carbon stocks for a Pacific island nation based on 135 sediment cores from 47 sites across Fiji. Mean organic carbon (OC) stocks were 5.6 ± 2.5 Mg C ha −1 (upper 15 cm) and 11.7 ± 9.2 Mg C ha −1 (wholecore), representing values 2–12 times lower than global averages. National Tier 2 OC stocks were 114 Gg C (15cm) and 237 Gg C (wholecore) based on a satellite‐derived seagrass area of 203 km 2 . Application of Tier 1 defaults would overestimate these stocks by an order of magnitude. Variance partitioning showed that spatial heterogeneity at sub‐island scales dominated OC variability, whereas biological factors (species and seagrass cover) explained <10% variance. Statistical analyses using map‐derived geomorphic predictors showed that OC was controlled primarily by hydrodynamic setting. The dominant controls on wholecore stocks were export_distance (proximity to deep channels, lagoons, reef slopes) and wind‐wave exposure, with threshold effects at ∼700 m export_distance and ∼20% exposure. Near‐surface (15cm) stocks were additionally influenced by seagrass cover and local seabed slope. These findings suggest that Fijian seagrass meadows function more as carbon outwelling systems than local sedimentary sinks, potentially transferring carbon to adjacent deep‐ocean basins. This study demonstrates a transferable framework for Tier 2 carbon estimates. However, our results emphasize that island‐reef geomorphology must be considered when interpreting the magnitude and climate relevance of sediment carbon pools in small‐island settings.
🔗 Provenance — このレコードを発見したソース
- crossref https://doi.org/10.1029/2026gb009079first seen 2026-05-14 23:55:41
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