Salas-Rabaza Julio A, Yáñez-Espinosa Laura, Cejudo Eduardo, Cerón-Aguilera Gabriela, Us-Santamaría Roberth, Andrade José Luis
Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán A.C., Calle 43 No. 130, Chuburná de Hidalgo, 97205, Mérida, Yucatan, Mexico.
Instituto de Investigación de Zonas Desérticas, Universidad Autónoma de San Luis Potosí, Altair No. 200, Col del Llano, 78377, San Luis Potosí, S.L.P., Mexico.
Sci Rep. 2024 Aug 8;14(1):18449. doi: 10.1038/s41598-024-68822-9.
Although mangrove forests are great carbon sinks, they also release carbon dioxide (CO) from soil, plants, and water through respiration. Many studies have focused on CO effluxes only from soils, but the role of biogenic structures such as pneumatophore roots has been poorly studied. Hence, CO effluxes from pneumatophores were quantified at sediment-air (non-flooded sediment) and water-air (flooded sediment) interfaces along a salinity gradient in three mangrove types (fringe, scrub, and basin) dominated by Avicennia germinans during the dry and rainy seasons in Yucatan, Mexico. Pneumatophore abundance explained up to 91% of CO effluxes for scrub, 87% for fringe, and 83% for basin mangrove forests at the water-air interface. Overall, CO effluxes were inversely correlated with temperature and salinity. The highest CO effluxes were in the fringe and the lowest were in the scrub mangrove forests. Flooding decreased CO effluxes from the dry to the rainy season in all mangrove forests. These results highlight the contribution of pneumatophores to mangrove respiration, and the need to include them in our current carbon budgets and models, but considering different exchange interfaces, seasons, and mangrove ecotypes.
尽管红树林是巨大的碳汇，但它们也通过呼吸作用从土壤、植物和水中释放二氧化碳（CO₂）。许多研究仅关注土壤中的CO₂排放，但对诸如呼吸根等生物结构的作用研究甚少。因此，在墨西哥尤卡坦半岛旱季和雨季期间，对由白骨壤主导的三种红树林类型（边缘型、灌丛型和盆地型），沿着盐度梯度在沉积物 - 空气（非水淹沉积物）和水 - 空气（水淹沉积物）界面处对呼吸根的CO₂排放进行了量化。在水 - 空气界面，呼吸根丰度对灌丛型红树林CO₂排放的解释率高达91%，对边缘型为87%，对盆地型为83%。总体而言，CO₂排放与温度和盐度呈负相关。CO₂排放最高的是边缘型红树林，最低的是灌丛型红树林。水淹使所有红树林从旱季到雨季的CO₂排放减少。这些结果突出了呼吸根对红树林呼吸作用的贡献，以及将其纳入当前碳预算和模型的必要性，但要考虑不同的交换界面、季节和红树林生态类型。
