HR: 09:45h
AN: B31B-08 INVITED     [PDF]
TI: A Science Plan for Integrated Studies of Coupled Biosphere-Atmosphere Carbon and Nitrogen Cycles
AU: * Carroll, M
EM: mcarroll@umich.edu
AF: Departments of Atmospheric, Oceanic, and Space Sciences and Chemistry, University of Michigan, 2455 Hayward St, Ann Arbor, MI 48109-2143 United States
AU: Bertman, S B
EM: bertman@wmich.edu
AF: Department of Chemistry, Western Michigan University, 3440 Wood Hall, Kalamazoo, MI 49008-3842 United States
AU: Guenther, A
EM: guenther@ucar.edu
AF: Atmospheric Chemistry Division, National Center for Atmospheric Research, 1850 Table Mesa Drive, Boulder, CO 80305 United States
AU: Holland, E A
EM: eholland@ucar.edu
AF: Atmospheric Chemistry Division, National Center for Atmospheric Research, 1850 Table Mesa Drive, Boulder, CO 80305 United States
AU: Shepson, P B
EM: pshepson@purdue.edu
AF: Departments of Chemistry and Earth and Atmospheric Sciences, Purdue University, 1393 Brown Building, West Lafayette, IN 47907-1393 United States
AU: Sparks, J P
EM: jps66@cornell.edu
AF: Department of Ecology and Evolutionary Biology, Cornell University, E409 Corson Hall, Ithaca, NY 14853 United States
AB: Human activities, such as the burning of fossil fuels and the use of nitrogen fertilizers, have approximately doubled levels of reactive nitrogen in the biosphere. This perturbation has the potential to alter fundamental processes in terrestrial ecosystems where composition, diversity, and productivity are largely controlled by the availability of nitrogen. A variety of theoretical and experimental studies indicate that nitrogen inputs have a direct impact on fluxes of carbon into ecosystems controlling both CO2 assimilation and the exchange of carbon-based trace gases. In some systems, plant growth and carbon storage appear to be enhanced by nitrogen addition. In contrast, other systems exhibit stagnant or declining plant growth with nitrogen addition as the ecosystem becomes N-saturated and susceptible to stressors such as soil acidification and ozone damage. The magnitudes of the nitrogen and carbon responses appear to depend directly on the pathway and magnitude of nitrogen flux into ecosystems. However, the pathway of nitrogen entry into ecosystems, the chemical species of that nitrogen and its level of incorporation into plant and soil biomass pools are poorly understood in many, if not all, ecosystems. A workshop was held in Boulder, Colorado, in November 2003 to develop a science plan to address the critical need to integrate leaf-level plant physiology, ecosystem, and atmospheric chemistry perspectives to determine the fate of nitrogen and thus carbon in terrestrial systems. Participants brought expertise in plant physiological ecology, biochemistry, soil microbiology, biogeochemistry, atmospheric chemistry, biosphere/atmosphere fluxes, and integrated modeling. On behalf of all participants, we present here the prioritized results of the workshop; including gaps in understanding, technological challenges of integrating biological, ecosystem and atmospheric compartments of carbon and nitrogen cycling, feedbacks in carbon and nitrogen cycle coupling that are likely to produce non-linear responses in the earth system, and identified resource needs for near-term research aimed at reducing uncertainties.
DE: 0315 Biosphere/atmosphere interactions
DE: 0322 Constituent sources and sinks
DE: 0400 Biogeosciences
DE: 1600 GLOBAL CHANGE (New category)
DE: 1615 Biogeochemical processes (4805)
SC: Biogeosciences [B]
MN: 2003 Fall Meeting