OOS 25

Disrupted Nitrogen Cycling in the Tropics: Tracking the Effects of Global Change Impacts on N Biogeochemistry from Soil to Stream

Global change impacts to the nitrogen cycle include those precipitated by land-use change, subsequent land management practices, increased levels of N deposition, and changes to global or regional climate. Those disruptions often affect multiple connected pools and fluxes of N, meaning disruptions to the nitrogen cycle can have cascading effects on how N moves around the ecosystem, with multiple ecological implications. Moreover, how global change impacts N in the tropics is poorly understood, where there exist both open questions about how the N cycle operates as well as many novel global change impacts. In this session, experts will discuss impacts on the N cycle in tropical ecosystems stemming from various global change pressures, with a particular focus on either tracing N cycle impacts within ecosystems (e.g., measuring changes to the N cycle from soils to streams and beyond) or modeling N impacts at larger scales (e.g., strategies to integrate impacts by scaling from field measurements to modeling frameworks). Given that global change impacts on nitrogen rarely, if ever, affect a limited set of variables, how can scientists use integrative strategies to sufficiently characterize and monitor tropical disruptions of the nitrogen cycle? In particular, this session has three objectives: 1) to review trends in the major global change impacts affecting the N cycle across the tropics, 2) to investigate changes to the N cycle in diverse tropical ecosystems, and 3) to provide examples of various whole-ecosystem and scaling approaches for estimating N cycle effects. Speakers will discuss primary research conducted across the pan-tropics from a mix of perspectives – included are talks appealing to ecosystem ecologists, soil scientists, land change scientists, microbial ecologists, and ecohydrologists given by researchers from early-career to established scientists. This session will provide an overview of how the N cycle is changing and what empirical, modeling, or integrative frameworks can be used to synthesize ecosystem-wide impacts, making it useful for scientists operating at diverse scales and in systems across the tropics.