Carbon dioxide, temperature, nitrogen pollution and sea level are all on the rise. Coastal wetlands are on the front lines of these global changes. Understanding how they respond requires a commitment to long-term research, composed of rich data sets and careful observations. This forms the heart of the Smithsonian’s Global Change Research Wetland.
The research site has been home to tidal wetland ecology studies for more than four decades. Over the years, it has become a premier location for field experiments exploring global change. Scientists use the 70 hectares of marsh to examine the role of wetlands in the present Chesapeake Bay and to predict what the future holds for coastal wetland ecosystems as they cope with change.
Wetlands provide some of nature’s most valuable ecosystem services. They improve water quality, serve as nurseries and habitat for wildlife, mitigate the damage of hurricanes and sequester carbon. Tidal wetlands support healthy estuaries and robust coastal communities.
One of the most enduring experiments hosted at the Smithsonian’s Global Change Research Wetland had its genesis in the question of whether plants would be a carbon sink as CO2 levels rise. That study began in 1987 and continues to this day. The site is also home to three other major studies, each building on the body of data that has been amassed over the decades. The main research questions include:
- Do plant responses to elevated atmospheric CO2 change over time?
- Does water pollution influence ecosystem responses to elevated CO2?
- Will global change help wetlands survive sea-level rise?
- Does elevated CO2 promote invasion by non-native plants?
There have been dozens of papers published with data from these studies. Some of the findings include:
- High levels of carbon dioxide consistently improved the growth of certain plant species over more than a quarter century of treatment.
- Future high levels of carbon dioxide will help many tidal wetlands rise in elevation by creating new soil faster. This implies an improved ability to cope with the accelerated pace of sea-level rise.
- Nitrogen pollution favors different plant species than elevated carbon dioxide. When the two are combined, the positive influence of elevated carbon dioxide on plant growth is reduced.