@article{fdi:010096398,
  title = {{T}he dual climate role of seagrass meadows in {A}rcachon {B}ay},
  author = {{D}olivet-{M}ar{\'e}chal, {M}. and {S}chmidt, {S}. and {C}ognat, {M}. and {S}chübert, {C}. and {G}ervaix, {J}. and des {C}hatelliers, {C}. {C}. and {L}abourdette, {N}. and {B}ertrand, {I}. and {R}ossi, {L}. {M}. and {D}ugu{\'e}, {R}{\'e}mi and {A}hr, {M}. and {R}ichaume, {A}. and {L}e {R}oux, {X}. and {F}lorio, {A}.},
  editor = {},
  language = {{ENG}},
  abstract = {{V}egetated coastal ecosystems such as seagrass meadows are increasingly recognized as key contributors to climate regulation. {A}cting as blue carbon sinks, they exhibit carbon burial rates up to 30-50 times higher than those of terrestrial forest soils, thereby storing large amounts of organic carbon in their sediments. {H}owever, these benefits may be partly offset by the release of greenhouse gases ({GHG}), particularly methane ({CH}4) and nitrous oxide ({N}2{O}), which possess a much higher global warming potential than {CO}2. {C}omparing seagrass meadows to bare sediments helps identify their specific role as blue carbon ecosystems. {I}n this study, we assessed carbon accumulation rates ({CAR}) together with in situ fluxes of {CH}4 and {N}2{O} in {Z}ostera noltii seagrass meadows and adjacent bare sediments within {A}rcachon {B}ay, {F}rance, which hosts {E}urope's largest {Z}. noltii meadows. {O}ur results demonstrate that seagrass areas exhibit {CAR} values that are 2.5 times higher, highlighting their superior carbon burial capacity. {H}owever, {GHG} emissions from seagrass meadows were 3.5 times higher than those from bare sediments, offsetting 28.7 +/- 0.3% of the estimated net climate benefit provided by carbon burial across the bay. {H}ydrodynamic conditions influence this balance: sheltered areas promote organic matter accumulation but also amplify {GHG} emissions. {D}espite these trade-offs, {Z}. noltii meadows still provide a net climate benefit 2.2 times greater than bare sediments, emphasizing their significant contribution to climate regulation. {T}hese findings highlight the dual nature of seagrass meadows as both carbon sinks and {GHG} sources. {I}ncorporating {GHG} flux estimates into blue carbon assessments will improve global model predictions and guide better conservation and restoration strategies.{G}raphical {A}bstract{T}his graphical abstract provides a concise and visually engaging summary of the study assessing the net climate benefits of seagrass meadows in {A}rcachon {B}ay, {F}rance. {T}he comparison between seagrass meadows with adjacent bare sediments at seven study sites with six replicates for each sediment type, highlighting the dual processes of carbon burial and greenhouse gas ({GHG}) fluxes ({CH}4 and {N}2{O}). {D}ownward green arrows represent the burial of organic carbon in sediments, while upward red arrows illustrate gaseous emissions to the atmosphere. {T}he balance between these opposing fluxes is central to understanding the overall climate impact of coastal ecosystems. {T}he bar plots emphasizes that, although seagrass meadows bury carbon at rates 2.5 times higher than bare sediments, they also release 3.5 times more {GHG}, offsetting part of their climate benefit. {I}mportantly, the net climate contribution of seagrass meadows remains 2.2 times greater than that of bare sediments. {B}y distilling the study into a clear and intuitive image, this graphical abstract provides readers with a rapid understanding of the research without reading the full manuscript. {I}t underscores the importance of integrating both carbon burial and {GHG} fluxes into blue carbon assessments and highlights the value of conserving and restoring seagrass meadows to mitigate climate change, providing actionable insights for their restoration and management.},
  keywords = {{B}lue carbon ; {S}eagrass meadows ; {C}limate regulation ; {C}oastal greenhouse gas emissions ; {C}arbon burial ; {C}arbon cycle ; {M}ethane fluxes ; {N}itrous oxide fluxes ; {FRANCE} ; {ATLANTIQUE} ; {ARCACHON} {BASSIN}},
  booktitle = {},
  journal = {{E}arth {S}ystems and {E}nvironment},
  volume = {[{E}arly access]},
  numero = {},
  pages = {[17 p.]},
  ISSN = {2509-9426},
  year = {2026},
  DOI = {10.1007/s41748-026-01029-2},
  URL = {https://www.documentation.ird.fr/hor/fdi:010096398},
}