OOS 25
Disrupted Nitrogen Cycling in the Tropics: Tracking the Effects of Global Change Impacts on N Biogeochemistry from Soil to Stream

Tuesday, August 11, 2015: 1:30 PM-5:00 PM
310, Baltimore Convention Center
Organizer:
Christine S. O'Connell
Co-organizers:
Gillian Galford and Marcia N. Macedo
Moderator:
Christine S. O'Connell
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.
1:30 PM
Nitrogen management challenges in major watersheds of South America
Mercedes MMC Bustamante, Universidade de Brasilia; Luiz A. Martinelli, University of São Paulo; Tibisay Perez, Instituto Venezolano de Investigaciones Científicas (IVIC); Sorena Marquina, Instituto Venezolano de Investigaciones Científicas (IVIC); Rafael Rasse, Instituto Venezolano de Investigaciones Científicas (IVIC); Jean Ometto, 4Instituto Nacional de Pesquisas Espaciais; Silvia R. M. Lins, University of Sao Paulo; Felipe S. Pacheco, Instituto de Pesquisas Espaciais
1:50 PM
Nitrogen and phosphorus fertilization alters biological nitrogen fixation in lowland tropical rainforest
Benjamin Sullivan, University of Nevada, Reno; Megan K. Nasto, University of Montana; Silvia Alvarez-Clare, North Central College; Sasha Reed, U.S. Geological Survey; Cory C. Cleveland, University of Montana
2:10 PM
Tracking the fate of nitrogen fertilizers in intensively cropped watersheds in southeastern Amazonia
Marcia N. Macedo, Woods Hole Research Center; Shelby Hayhoe Riskin, Brown University; Christopher Neill, Marine Biological Laboratory; Kathijo Jankowski, University of Washington, Marine Biological Laboratory; Michael T. Coe, Woods Hole Research Center; Christine S. O'Connell, University of California, Berkeley; Alex V. Krusche, CENA/USP; R Chelsea Nagy, Brown University
2:30 PM
Nitrogen fixation in dry tropical forests
Maria G. Gei, University of Minnesota; Jennifer S. Powers, University of Minnesota
2:50 PM
One size does not fit all: Multi-scale heterogeneity in the lowland tropical N cycle
Alan Townsend, Duke University; Cory C. Cleveland, University of Montana; Gregory Asner, Carnegie Institution for Science; Stephen Porder, Brown University; Philip G. Taylor, Duke University; Brooke B. Osborne, Brown University; Megan K. Nasto, University of Montana; Will R. Wieder, National Center for Atmospheric Research; Benjamin Sullivan, University of Nevada, Reno
3:10 PM
3:20 PM
Nitrogen deposition and its fate in N-rich tropical forests of Southern China
Xiankai Lu, Chinese Academy of Sciences; Geshere Abdisa Gurmesa, Chinese Academy of Sciences; Qinggong Mao, Chinese Academy of Sciences; Kaijun Zhou, Chinese Academy of Sciences; Edith Bai, Instituted of Applied Ecology, Chinese Academy of Sciences; Frank Gilliam, University of West Florida; Per Gundersen, University of Copenhagen; Xiaoping Pan, Chinese Academy of Sciences; Jiangming Mo, Chinese Academy of Sciences
3:40 PM
Agriculture in the Neotropics and ecosystem changes to the N cycle
Silvia Rafaela M. Lins, University of Sao Paulo; Luiz A. Martinelli, University of Sao Paulo, Brazil; Eric Roy, Brown University; Stephen Porder, Brown University
4:00 PM
Assessing the effects of soybean–maize cropping on soil N biogeochemistry and N2O emissions in the Brazilian Amazon using the DNDC model
Ciniro Costa Jr., Woods Hole Research Center, Marine Biological Laboratory; Christine S. O'Connell, University of California, Berkeley; Kathijo Jankowski, Marine Biological Laboratory; Christopher Neill, Marine Biological Laboratory; Gillian L. Galford, University of Vermont; Marcia N. Macedo, Woods Hole Research Center; Carlos Eduardo Cerri, University of São Paulo; Michael T. Coe, Woods Hole Research Center
4:20 PM
Nitrogen from soy and maize agriculture influences nutrient export and stream productivity in headwater streams of the Amazon basin
Kathijo Jankowski, Marine Biological Laboratory; Shelby Riskin, Marine Biological Laboratory; Marcia N. Macedo, Woods Hole Research Center; Christopher Neill, Marine Biological Laboratory; Linda A. Deegan, Marine Biological Laboratory; Alex V. Krusche, Universidade de São Paulo; Michael T. Coe, Woods Hole Research Center