Past, Present, and Future Atmospheric Nitrogen Deposition

Abstract

Reactive nitrogen emissions into the atmosphere are increasing as a result of human activities, affecting nitrogen deposition to the surface and impacting the productivity of terrestrial and marine ecosystems. An atmospheric chemistry-transport model [Tracer Model 4 of the Environmental Chemical Processes Laboratory (TM4-ECPL)] is here used to calculate the global distribution of total nitrogen deposition, accounting for the first time for both its inorganic and organic fractions in gaseous and particulate phases and past and projected changes due to anthropogenic activities. The anthropogenic and biomass-burning Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) historical and RCP6.0 and RCP8.5 emissions scenarios are used. Accounting for organic nitrogen (ON) primary emissions, the present-day global nitrogen atmospheric source is about 60% anthropogenic, while total N deposition increases by about 20% relative to simulations without ON primary emissions. About 20%-25% of total deposited N is ON. About 10% of the emitted nitrogen oxides are deposited as ON instead of inorganic nitrogen (IN), as is considered in most global models. Almost a threefold increase over land (twofold over the ocean) has been calculated for soluble N deposition due to human activities from 1850 to present. The investigated projections indicate significant changes in the regional distribution of N deposition and chemical composition, with reduced compounds gaining importance relative to oxidized ones, but very small changes in the global total flux. Sensitivity simulations quantify uncertainties due to the investigated model parameterizations of IN partitioning onto aerosols and of N chemically fixed on organics to be within 10% for the total soluble N deposition and between 25% and 35% for the dissolved ON deposition. Larger uncertainties are associated with N emissions.

Global deposition of total reactive nitrogen oxides from 1996 to 2014 constrained with satellite observations of NO<sub>2</sub> columns

“…NO y deposition was estimated to be around 45-50 Tg N yr −1 in the late 1990s and early 2000s, representing a three-to fourfold increase since the preindustrial era (Dentener et al, 2006;Kanakidou et al, 2016;Lamarque et al, 2013). A substantial range exists in the trajectory of global NO y deposition beyond the year 2000, depending on the emission scenario.…”

Multi-model study of HTAP II on sulphur and nitrogen deposition

“…Dentener et al (2006) the Unites States is found to deviate with inferential dry deposition data. Kanakidou et al (2016) used the ACCMIP simulation results under historical, RCP6.0 and RCP 8.5 emission scenarios to 90 estimate the changes in N deposition driven by human activity in the past (1850), present (2005) and future (2050). Their results showed that organic nitrogen (ON) from primary emission and secondary organic aerosol (SOA) accounted for 20-30% of total N deposition.…”

“…This benefit is compensated by increasing NH x deposition because no limitation is implemented on NH 3 emission (Kanakidou et al, 2016;Li et al, 2016). Some regions have small increases in the ratio of NH x deposition, such as North Europe (Norway) (5%), Southeast Asia (10%) and Western Australia (10%).…”

Stimulation of long-term ammonium nitrogen deposition on methanogenesis by Methanocellaceae in a coastal wetland

“…Atmospheric nitrogen deposition caused by human activities has been receiving much attention (Kanakidou et al, 2016). The annual anthropogenic input of nitrogen in ecosystems has increased tenfold over the past 150 years, and it is predicted to be 2-3 times the current level in the 2050s (Sutton and Bleeker, 2013).…”