The Case for a Critical Zone Science Approach to Research on Estuarine and Coastal Wetlands in the Anthropocene

As the focus of land-sea interactions, estuarine and coastal ecosystems perform numerous vital ecological service functions, although they are highly vulnerable to various kinds of disturbance, both directly and indirectly related to human activity, that have attracted much recent attention. Critical zone science (CZS) has emerged as a valuable conceptual framework that focuses on quantitative interactions between diverse components of the environment and is able to integrate anthropogenic disturbance with a view to predicting future trajectories of change. However, coastal and estuarine environments appear to have been overlooked in CZS and are notably under-represented, indeed not explicitly represented at all, in the global network of critical zone observatories (CZOs). Even in the wider network of environmental observatories globally, estuarine and coastal wetland ecosystems are only very rarely an explicit focus. Further strengthening of integrated research in coastal and estuarine environments is required, more especially given the threats these ecosystems face due to growing population at the coast and against the background of climate change and sea level rise. The establishment of one or more CZOs, or their functional equivalents, with a strong focus on estuarine and coastal wetlands, should be urgently attended to.