College of the Life and Environment Science, Central South University of Forestry and Technology, Changsha, China.
National Engineering Laboratory for Applied Technology of Forestry & Ecology in South China, Central South University of Forestry and Technology, Changsha, China.
Glob Chang Biol. 2024 Apr;30(4):e17280. doi: 10.1111/gcb.17280.
Coastal wetlands play an important role in regulating atmospheric carbon dioxide (CO) concentrations and contribute significantly to climate change mitigation. However, climate change, reclamation, and restoration have been causing substantial changes in coastal wetland areas and carbon exchange in China during recent decades. Here we compiled a carbon flux database consisting of 15 coastal wetland sites to assess the magnitude, patterns, and drivers of carbon fluxes and to compare fluxes among contrasting natural, disturbed, and restored wetlands. The natural coastal wetlands have the average net ecosystem exchange of CO (NEE) of -577 g C m year, with -821 g C m year for mangrove forests and -430 g C m year for salt marshes. There are pronounced latitudinal patterns for carbon dioxide exchange of natural coastal wetlands: NEE increased whereas gross primary production (GPP) and respiration of ecosystem decreased with increasing latitude. Distinct environmental factors drive annual variations of GPP between mangroves and salt marshes; temperature was the dominant controlling factor in salt marshes, while temperature, precipitation, and solar radiation were co-dominant in mangroves. Meanwhile, both anthropogenic reclamation and restoration had substantial effects on coastal wetland carbon fluxes, and the effect of the anthropogenic perturbation in mangroves was more extensive than that in salt marshes. Furthermore, from 1980 to 2020, anthropogenic reclamation of China's coastal wetlands caused a carbon loss of ~3720 Gg C, while the mangrove restoration project during the period of 2021-2025 may switch restored coastal wetlands from a carbon source to carbon sink with a net carbon gain of 73 Gg C. The comparison of carbon fluxes among these coastal wetlands can improve our understanding of how anthropogenic perturbation can affect the potentials of coastal blue carbon in China, which has implications for informing conservation and restoration strategies and efforts of coastal wetlands.
沿海湿地在调节大气二氧化碳（CO）浓度方面发挥着重要作用，对减缓气候变化做出了重大贡献。然而，近几十年来，气候变化、填海造地和恢复已经导致中国沿海湿地面积和碳交换发生了重大变化。在这里，我们编制了一个碳通量数据库，其中包含 15 个沿海湿地站点，以评估碳通量的大小、模式和驱动因素，并比较不同自然、受干扰和恢复湿地之间的通量。自然沿海湿地的 CO 净生态系统交换（NEE）平均值为-577 g C m-1 yr-1，其中红树林的 NEE 值为-821 g C m-1 yr-1，盐沼的 NEE 值为-430 g C m-1 yr-1。自然沿海湿地的二氧化碳交换存在明显的纬度格局：随着纬度的增加，NEE 增加，而生态系统的总初级生产力（GPP）和呼吸作用减少。不同的环境因素驱动红树林和盐沼之间 GPP 的年际变化；在盐沼中，温度是主要的控制因素，而在红树林中，温度、降水和太阳辐射是共同的控制因素。同时，人为开垦和恢复对沿海湿地碳通量都有重大影响，而且人为干扰对红树林的影响比盐沼更为广泛。此外，从 1980 年到 2020 年，中国沿海湿地的人为开垦导致了约 3720 Gg C 的碳损失，而 2021-2025 年期间的红树林恢复项目可能会使恢复后的沿海湿地从碳源转变为碳汇，净碳增益为 73 Gg C。这些沿海湿地之间的碳通量比较可以提高我们对人为干扰如何影响中国沿海蓝碳潜力的理解，这对告知沿海湿地的保护和恢复策略和努力具有重要意义。
