Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China.
Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China.
Environ Res. 2023 Dec 1;238(Pt 1):117110. doi: 10.1016/j.envres.2023.117110. Epub 2023 Sep 9.
Understanding the control mechanisms of carbon dioxide (CO) emissions in intertidal wetland sediments is beneficial for the concern of global carbon biogeochemistry and climate change. Nevertheless, multiple controls on CO emissions from intertidal wetland sediments to the atmosphere still need to be clarified. This study investigated the effect of tidal action on CO emissions from salt marsh sediments covered by Spartina alterniflora in the Jiaozhou Bay wetland using the static chamber method combined with an infrared CO detector. The results showed that the CO emission fluxes from the sediment during ebb tides were higher than those during flood tides. The whole wetland sediment acted as a weak source of atmospheric CO (average flux: 24.44 ± 16.80 mg C m h) compared to terrestrial soils and was affected by the cycle of seawater inundation and exposure. The tidal influence on vertical dissolved inorganic carbon (DIC) transport in the sediment was also quantitated using a two-end member mixing model. The surface sediment layer (5-15 cm) with maximum DIC concentration during ebb tides became the one with minimum DIC concentration during flood tides, indicating the DIC transport from the surface sediment to seawater. Furthermore, aerobic respiration by microorganisms was the primary process of CO production in the sediment according to 16 S rDNA sequencing analysis. This study revealed the strong impact of tidal action on CO emissions from the wetland sediment and provided insights into the source-sink pattern of CO and DIC at the land-ocean interface.
了解二氧化碳（CO）排放的控制机制在潮间带湿地沉积物中有利于关注全球碳生物地球化学和气候变化。然而，仍需要阐明多种控制因素对潮间带湿地沉积物向大气中排放 CO 的影响。本研究采用静态箱法结合红外 CO 检测仪，研究了潮汐作用对胶州湾湿地覆盖互花米草盐沼沉积物中 CO 排放的影响。结果表明，落潮期间沉积物的 CO 排放通量高于涨潮期间。整个湿地沉积物相对于陆地土壤而言，是大气 CO 的弱源（平均通量：24.44±16.80mg C m h），并受海水淹没和暴露周期的影响。还使用双端元混合模型定量了潮汐对沉积物中垂直溶解无机碳（DIC）迁移的影响。落潮期间 DIC 浓度最大的表层沉积物（5-15cm）在涨潮期间成为 DIC 浓度最小的沉积物，表明 DIC 从表层沉积物向海水的迁移。此外，根据 16S rDNA 测序分析，微生物的需氧呼吸是沉积物中 CO 产生的主要过程。本研究揭示了潮汐作用对湿地沉积物 CO 排放的强烈影响，并深入了解了陆海界面 CO 和 DIC 的源汇格局。
