Balancing EcosystemAtmosphere Exchanges Across Wetlandscapes for Advancing Climate Solutions

Nature-based climate solutions (NbCS) are increasingly promoted to mitigate climate change by conserving, restoring, and managing ecosystems. Coastal wetlands are especially promising NbCS because waterlogged and saline conditions slow carbon (C) mineralization, enabling long-term soil C storage. Yet most coastal regions are not composed of a single habitat type; instead, they form wetlandscapes, which are mosaics of natural marshes, seagrass meadows, and, in many deltas, flooded agricultural systems such as rice paddies. These agricultural wetlands, among the most extensive managed wetlands globally, offer additional mitigation opportunities through management practices that reduce methane (CH4) emissions. However, despite growing interest and investment, NbCS implementation is limited by major knowledge gaps: high uncertainty in CH4 and nitrous oxide (N2O) fluxes, limited understanding of how management or disturbance in one part of a wetlandscape propagates and alters GHG emissions in connected ecosystems, and a mismatch between plot-level measurements, ecosystem-scale processes, and the landscape and regional scales at which policies operate. The BEACONS project addresses these gaps by quantifying the full greenhouse gas (GHG) balance (CO2, CH4, and N2O), across a representative wetlandscape in the Ebro Delta, integrating natural and agricultural wetlands. Using eddy covarince flux towers, plot-level chamber flux measurements, soil C burial assessments, and spatial surveys of dissolved GHGs, the project will reduce uncertainties in non-CO2 emissions, determine how disturbance and management interentions alter the biogeochemical balance between C sequestration and GHG release, and evaluate cross-ecosystem linkages that shape net climate effects. Remote sensing will play a central role: by combining hyperspectral, multispectral, and drone-based imagery with ground observations, BEACONS will develop spatially explicit proxies of wetland GHG sinks and sources. These products will allow robust upscaling of fluxes from plots to landscapes, bridging the gap between project-scale monitoring and regional policy needs. The Ebro Delta provides an ideal natural laboratory, encompassing rice paddies, coastal marshes, and seagrass meadows exposed to gradients in salinity, hydrological management, and nutrient inputs. Three eddy covariance towers managed by the research team already offer continuous GHG flux measurements, enabling the project to evaluate NbCS potential at high spatial and temporal ressolution. By integrating plot-level, ecosystem-scale, and remote sensing data, BEACONS will generate high-resolution maps of mitigation potential and provide a transferable framework for monitoring and verifying NbCS in similar wetlandscapes nationally, such as the Guadalquivir Delta and Albufera. This framework will also be applicable to larger wetland mosaics worldwide, where flooded agricultural systems coexist with blue carbon ecosystems.