Assessment of the effects of water salinity on greenhouse gas fluxes and carbon balance in coastal wetlands

Part I of this study gives an overlook on coastal wetlands and their role climate change mitigation, as reservoirs for organic carbon in soils. Part II investigates the impact of salinity on greenhouse gas emissions, in four wetlands along the northeast Adriatic coast. Over a year, comprehensive measurements, including soil properties, CH4 and CO2 fluxes, and water parameters, revealed a significant reduction in CH4 emissions at water heights exceeding 50 cm. Notably, temperature and irradiance strongly influenced CH4 emissions, with distinctions observed between freshwater and brackish systems. Part III delves into the relationship between microbial communities, biogeochemical processes, and potential climate-related feedbacks in temperate coastal wetlands. Addressing the dual role of these ecosystems as carbon sinks and CH4 sources, the study characterizes microbial communities using advanced sequencing techniques. Focused on three temperate wetlands along a salinity gradient, results highlight the prevalence of sulfur-reducing bacteria in salinized sites, impacting CH4 and CO2 emissions. This section underscores the need for a better understanding of wetland ecosystems, salinity effects, and climate-related feedbacks to inform conservation and climate change mitigation strategies. In Part IV, the study aims at reviewing hydrological processes and carbon dynamics in temperate wetlands. Analyzing data extracted from 50 wetlands, this section examines the interplay between environmental variables and their significant impact on CH4 budgets and carbon balances. The water column height, emerges as a critical factor influencing wetland biogeochemistry. Seasonal dynamics, including alternating inundation and drought periods, affect redox conditions, impacting CH4 generation by methanogenic bacteria. This chapter highlights some limitation of the sampling techniques used in this research. Part V resumes the finals remarks of this study. The multidisciplinary approach of this work seeks to enhance carbon storage strategies, combat climate change, and better understand the role of temperate coastal wetlands in climate change mitigation.