Collaborative Research: MRA: PanAm Peat: Understanding Water and Carbon Cycling across the Pan-American Tropical Peatland Biome

Tropical peatlands are believed to play an outsized role in the global carbon cycle. Despite their relatively small extent, these ecosystems act as some of the strongest long-term terrestrial carbon sinks on Earth. They are also believed to constitute some of the largest natural methane sources. However, these claims are anchored in very little field data. In South America, which may encompass the largest area of tropical peatlands in the world, we do not know where peatlands are, what controls the rate of peat formation, which conditions constrain methane emissions, and whether these ecosystems are resilient to climate change. This project focuses on the PanAm peatlands, which we define as the natural lowland peatlands found across the tropical region of the American continent, from 20 degrees N to 20 degrees S. The selected approximately 80 study sites encompass broad environmental gradients and include distinct climate areas such as the Caribbean coast and the Amazon basin. The main approach involves using a novel field sampling kit, which will allow for consistent field data collection at the continental scale. The ultimate goals of this research are to gain new insights into peatland environments, and better constrain regional and global carbon budgets. Training the next generation of scientists is also a central component of this project. In addition to involving U.S. postdoctoral researchers, graduate students and undergraduate students, in-person field training will be offered to local scientists (including students) through workshops that will be held in the Caribbean and the Amazon. High-quality videos showing how to deploy instruments and take measurements using our field kit will also be developed in English and Spanish, and made available to all. Data analysis training will be offered to peatland scientists and students through hybrid workshops. Overall, this work will contribute to U.S. expertise in Earth System Science, increase capacity through student training, advance the peatland, wetland, and carbon cycling communities’ research agenda, and guide policy and land management decisions. Because tropical peatlands these ecosystems are being lost at a rate about three times faster than forests, it is critical to collect baseline information about their structure and function. This research undertakes a large number of systematic field measurements that will improve mechanistic understanding of plant-soil-water-nutrient-carbon interactions. This information is needed to build holistic representations of the different types of tropical peatlands that exist. These field data and statistical models will allow for predictive assessments of tropical peatland carbon input and output, with an emphasis on methane emissions. Ultimately, the project seeks to (1) identify the hydrological thresholds needed for peatland formation across the tropics, (2) quantify the key constraints on the rate of peat formation over space and time, and (3) document patterns of methane production, consumption, and emission at the ecosystem scale. This field-based research may lead to the development of new theoretical foundations needed to improve multiple modeling efforts. Recurring engagement with modelers is planned to help integrate these field data into peatland mapping algorithms, process-based peatland ecosystem models, and land surface models. A database that combines the new results with a literature synthesis of existing and ongoing measurements will be generated and archived in the Environmental Data Initiative repository. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.