Sediment properties influence seagrass sedimentary carbon stocks, challenging uniform blue carbon accounting

Unofficial AI-generated summary based on the public title and abstract. Not an official translation.

🔬研究者:Provides a rigorous method for assessing seagrass carbon stocks and identifies sediment properties as key predictors, informing future sampling designs and modeling.

🏢実務担当者:For entities involved in blue carbon projects or coastal management, this study underscores the need for site-specific measurements to avoid overestimating or underestimating carbon credits.

🏛政策担当者:Policy implications for national GHG inventories and blue carbon crediting schemes: stratification by hydrogeomorphic setting is necessary for accurate reporting.

Seagrass meadows are increasingly recognised as important blue carbon ecosystems, yet large uncertainties in regional sedimentary organic carbon (C org ) stocks limit their inclusion in greenhouse gas accounting. Northern Ireland supports extensive seagrass meadows across diverse hydrogeomorphic settings but lacks empirically derived carbon stock estimates. Here, we present the first regionally representative assessment of sedimentary C org storage in Northern Ireland seagrass meadows. Sediment cores were collected from nine intertidal and subtidal meadows and analysed for carbon content, sediment properties, and stable carbon isotopes, with adjacent unvegetated sediments used as references where available. Sediment C org stocks to 1 m depth averaged 109.7 ± 18.9 Mg C ha -1 but varied by more than an order of magnitude among sites (18.6 - 280.8 Mg C ha -1 ). Seagrass sediments retained higher carbon at depth than unvegetated sediments, indicating enhanced burial and carbon permanence, although surface carbon enhancement was highly site dependent. Multivariate analyses identified sediment properties, used as proxies for hydrodynamic setting, as dominant factors influencing carbon storage, with fine-grained, low-energy systems supporting substantially higher stocks per hectare than more exposed, coarse-grained environments. Stable isotope mixing models showed that sediment carbon commonly comprised a mixture of seagrass-derived and allochthonous material, indicating that high carbon stocks are not restricted to autochthonous production alone. These results show that seagrass carbon storage in Northern Ireland is highly heterogeneous, influenced by physical setting rather than seagrass presence alone, and must be represented using stratified, regionally resolved approaches in blue carbon accounting.

• openalex https://doi.org/10.3389/fmars.2026.1809172first seen 2026-06-17 05:54:52 · last seen 2026-06-17 07:14:15