Jacotot A. auteur aut IRD Marchand Cyril auteur aut IRD Allenbach M. auteur aut IRD text journalArticle eng text/pdf born digital access We performed a preliminary study to quantify CO2 and CH4 emissions from the water column within a Rhizophora spp. mangrove forest. Mean CO2 and CH4 emissions during the studied period were 3.35 +/- 3.62 mmolC m(-2) h(-1) and 18.30 +/- 27.72 mu molC m(-2) h(-1) , respectively. CO2 and CH4 emissions were highly variable and mainly driven by tides (flow/ebb, water column thickness, neap/spring). Indeed, an inverse relationship between the magnitude of the emissions and the thickness of the water column above the mangrove soil was observed. delta(CO2)-C-13 values ranged from -26.88 parts per thousand to -8.6 parts per thousand, suggesting a mixing between CO2-enriched pore waters and lagoon incoming waters. In addition, CO2 and CH4 emissions were significantly higher during ebb tides, mainly due to the progressive enrichment of the water column by diffusive fluxes as its residence time over the forest floor increased. Eventually, we observed higher CO2 and CH4 emissions during spring tides than during neap tides, combined to depleted delta(CO2)-C-13 values, suggesting a higher contribution of soil-produced gases to the emissions. These higher emissions may result from higher renewable of the electron acceptor and enhanced exchange surface between the soil and the water column. This study shows that CO2 and CH4 emissions from the water column were not negligible and must be considered in future carbon budgets in mangroves. specialized Water to atmosphere fluxes Greenhouse gas Blue carbon Carbon dioxide isotope Semi-arid mangrove forest NOUVELLE CALEDONIE PACIFIQUE SUD 082 021 032 631-632 334-340 2018 0048-9697 https://www.documentation.ird.fr/hor/fdi:010073072 10.1016/j.scitotenv.2018.03.006 0048-9697 [F B010073072] https://www.documentation.ird.fr/hor/fdi:010073072 https://www.documentation.ird.fr/intranet/publi/2018/06/010073072.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2018-07-03 2023-07-11 fdi:010073072 fre