Lane Charles R, Nahlik Amanda M, Christensen Jay, Golden Heather, Dumelle Michael, D'Amico Ellen, Olsen Anthony R
Ecosystem Processes Division, U.S. EPA, Office of Research and Development, Center for Environmental Measurement and Modeling, Athens, GA, USA.
Pacific Ecological Effects Division, U.S. EPA, Office of Research and Development, Center for Public Health and Environmental Assessment, Corvallis, OR, USA.
Earths Future. 2025 Apr 17;13(4):e2024EF005594. doi: 10.1029/2024EF005594.
Understanding wetland carbon stores and dynamics are critical to managing global carbon flux. Non-floodplain wetlands (NFWs) are hydrologically dynamic and globally prevalent inland wetlands distal to fluvial flowpaths, lacustrine-fringing areas, and geomorphic floodplains; >50% the world's remaining wetlands have been reported as NFWs. Quantifying NFW carbon stores and dynamics represents a substantive global carbon-budget gap. We analyze conterminous-US (CONUS) field-based data collected from nearly 2000 wetland sites sampled by the National Wetlands Condition Assessment (NWCA) representing ~38 Mha CONUS wetlands, asking: What is the mean soil organic carbon density and total carbon storage in different hydrogeomorphically classified wetland types? To what extent does soil organic carbon density and total carbon in NFWs differ from other wetland types? How does NFW soil organic carbon density and total carbon vary between altered and intact NFWs? We find that relative to other wetland types, NFWs are carbon-storing powerhouses, containing approximately 1.5x soil organic carbon per ha than other wetland types sampled. CONUS-wide, NFWs store more total carbon across every depth increment: ~2.0x than other wetland types. Further, wetland condition affects carbon dynamics: least impaired NFWs had 1.6x the soil organic carbon density found in intermediately disturbed wetlands and 1.8x the density of most-disturbed NFWs. These NWCA data, plus waning societal protections, suggests that carbon releases from NFW destruction across CONUS landscapes are likely to increase-perhaps markedly-in the coming years (e.g., through altered hydrology affecting atmospheric release of NFW-stored carbon as well as dissolved carbon export).
了解湿地碳储量和动态对于管理全球碳通量至关重要。非洪泛平原湿地（NFWs）水文动态变化大，是全球普遍存在的内陆湿地，远离河流径流路径、湖岸边缘地区和地貌洪泛平原；据报道，全球剩余湿地中有超过50%为非洪泛平原湿地。量化非洪泛平原湿地的碳储量和动态变化是全球碳预算中的一个重大缺口。我们分析了美国本土（CONUS）基于实地的数据，这些数据来自国家湿地状况评估（NWCA）对近2000个湿地地点的采样，代表约3800万公顷的美国本土湿地，提出以下问题：不同水文地貌分类的湿地类型中，土壤有机碳密度和总碳储量的平均值是多少？非洪泛平原湿地的土壤有机碳密度和总碳与其他湿地类型有何不同？非洪泛平原湿地的土壤有机碳密度和总碳在改变和未改变的非洪泛平原湿地之间如何变化？我们发现，相对于其他湿地类型，非洪泛平原湿地是碳储存的“动力源”，每公顷所含土壤有机碳比其他采样湿地类型多约1.5倍。在整个美国本土范围内，非洪泛平原湿地在每个深度增量下储存的总碳更多：比其他湿地类型多约2.0倍。此外，湿地状况会影响碳动态：受损最小的非洪泛平原湿地的土壤有机碳密度是中度受干扰湿地的1.6倍，是受干扰最严重的非洪泛平原湿地密度的1.8倍。这些国家湿地状况评估数据，加上社会保护力度的减弱，表明未来几年美国本土各地非洪泛平原湿地破坏导致的碳释放可能会增加——也许会显著增加（例如，通过改变水文状况影响非洪泛平原湿地储存碳的大气释放以及溶解碳输出）。
