Editorial: Wetland ecosystems as important greenhouse hotspots

Abstract

Editorial on the Research Topic Wetland ecosystems as important greenhouse hotspotsWetlands are highly valued for their rich diversity (flora and fauna), hydrological attributes, ecological productivity, and ecosystem services. Furthermore, wetlands behave as a potential source/sink of atmospheric greenhouse gases (GHG, especially CH 4 ) as well as supporting carbon (C) sequestration, thereby contributing to the global C balance. The dense vegetation patterns, algal activity, and terrestrial soils of wetland ecosystems regulate organic matter (OM) decomposition processes, producing a significant amount of global GHG (Lian et al.). Conversely, some types of wetlands may be more efficient at capturing atmospheric C than rainforests. Pant et al. (2003) highlighted that wetlands are invaluable C sinks, contributing the highest C density among terrestrial ecosystems, while floods suppress CO 2 emissions but also generate a significant amount of methane (Zhang et al., 2020). Although wetlands occupy only 5%-8% of the earth's land surface, they regulate ~68% of terrestrial soil C reserves, thereby playing a decisive role in global C budgets. In recent decades, anthropogenic activities in numerous catchments alter the geochemical process (Khan et al.). Moreover, rapid increases in urbanization have disturbed land use and land cover (LULC), thereby increasing atmospheric GHG concentrations. Globally, carbon dioxide (CO 2 ) has been increasing at 1.7 ppmv yr −1 (equivalent to 46% yr −1 ) resulting in global warming and numerous associated impacts on ecosystems and human societies. Thus, mitigation of global warming is a central theme of worldwide discourse (UNSECC, 2022).Wetland ecosystems have often been neglected, despite providing a wealth of provisioning, regulatory, cultural, and supporting services valuable to humans. Recently, Peng et al. ( 2022) quantified changes in CH 4 sources and atmospheric sinks in 2020 compared with 2019, finding that globally, "total anthropogenic emissions decreased by 1.2 ± .1 teragrams of methane per year (Tg CH 4 yr −1 ), fire emissions decreased by 6.5 ± .1 Tg CH 4 yr −1 yet wetland emissions increased by 6.0 ± 2.3 Tg CH 4 yr −1" . A balance between these exchanges is vital to understand how restoration or expansion of wetlands areas can help to mitigate climate change. Since the 1900s, due to LULC changes about 64%-71% of wetlands ecosystems have been degraded or lost, which has affected their nutrient concentrations and dynamics resulting in GHG emissions (Davidson, 2014). However, the state of those that remain is unclear. The prime goal of this Research Topic is to provide an opportunity for global scientists to understand wetland hydrology, the process and transport mechanism of OM degradation, and key factors influencing GHG emissions so that nature-based cimatic solutions can be implemented systematically Figure 1.

Perspectives on Drivers of Biodiversity and Environmental Changes in the Keta Lagoon Ramsar Site of Ghana

“…In complex coastal wetland ecosystems, inter-connecting rivers and streams are responsible for perennial enrichment of the entire system through regular transportation of nutrients, sediments and fresh water to nourish the system [63]. The authors established that freshwater flow into wetlands affects the physical aspects of wetlands as well as the flora, fauna and habitats of organisms in the system.…”