滨海地球关键带科学: 一个新兴的研究领域

The coastal Earth Critical Zone (CECZ), located in coastal plains and nearshore regions, is a complex and dynamic ecological interface shaped by interacting physical, chemical, and biological processes across land, ocean, and atmosphere. These interactions occur across multiple spatial and temporal scales, from molecular-level biogeochemical reactions in sediment porewater to large-scale oceanic and atmospheric circulation patterns. This CECZ exhibits an exceptionally high level of ecological functions, including primary production, nutrient cycling, and habitat provision, which in turn supports essential services like fisheries, water purification, and carbon storage. However, it also ranks among the most sensitive regions to both climate change and human disturbances. This paper systematically traces the origin and evolution of CECZ science, emphasizing its emergence as a critical frontier of interdisciplinary research. Previous research efforts were largely discipline-specific, ranging from coastal geomorphology to marine ecology and hydrology. Recent development of advanced methods, such as isotope ratio mass spectrometry, remote sensing, and numerical modeling, has increasingly facilitated integrated and system-level investigations. This transition has been crucial for understanding the complex feedback mechanisms and cascading effects that govern the evolution of the CECZ, highlighting the need for collaborative research across geological, biological, chemical, and physical sciences. For the first time, this study offers a precise spatial definition of the CECZ. Vertically, its boundaries extend from the lower limit of significant biological and chemical activities (i.e., the top of the subsurface fresh rock or the base of the aquifer system), to the upper reaches of the coastal vegetation canopy, where energy, water, and gas exchange with the atmosphere is most intense. Horizontally, it encompasses a diverse range of geomorphological units, including beaches, estuaries, salt marshes, and coastal cliffs. The structural evolution of CECZ is driven by a combination of natural and anthropogenic factors. Currently, the coastal region is grappling with a series of severe challenges, including accelerating sea-level rise, progressive coastal erosion, widespread wetland degradation, and rapid biodiversity loss. Despite significant research efforts, existing studies remain fragmented and often confined to single disciplines or localized issues, thus limiting our understanding of the complex and interconnected processes within the CECZ. This paper posits that the core of CECZ science lies in elucidating the intricate relationships among its structure, processes, functions, and services. Based on this new concept, five prioritized research directions are proposed: (i) the spatiotemporal evolution of the CECZ structure and its mechanisms; (ii) the coupling mechanisms between structure and processes; (iii) the mechanisms underlying ecological functions and services; (iv) the unique challenges and opportunities of coastal urbanization; and (v) ecosystem restoration and integrated management. To advance these research priorities, a new “Structure-Process-Function-Service” theoretical framework is proposed through multidisciplinary integration, long-term observational networks, and model-data fusion. It further calls for enhanced land-sea integrated governance and the development of Earth system science-based research paradigms, providing scientific foundations for addressing global changes and achieving human-environment synergies in coastal regions.