Drivers of N2O emissions from natural forests and grasslands differ in space and time

ARAUJO, P.; PIÑEIRO GUERRA, J:M; YAHDJIAN, L; ALVAREZ, C; ALVAREZ, C.; COSTANTINI, A.; CHALCO VERA, J.; DE TELLERÍA, J.; DELLA CHIESA, T.; LEWCZUK, N.; PETRASEK, M.; PICCINETTI, C.; PICONE, L.; PORTELA, S.; POSSE, G.; SEIJO, M.; VIDELA, C.; PIÑEIRO G

ECOSYSTEMS (NEW YORK. PRINT)

SPRINGER

Lugar: Berlin; Año: 2020

1432-9840

Understanding the drivers of greenhouse gas (GHG) emissions is one of the most47 critical global environmental challenges to mitigate the increasing global temperature.48 Nitrous oxide (N2O) emissions are highly variable in space and time and are controlled49 by multiple proximal drivers, i.e. those that affect N2O emissions directly and in short50 timescales, and distal or indirect drivers that influence emissions over long timescales.51 Here we present a quantification of N2O emissions in grasslands and forests throughout52 the Pampas and the Semiarid Chaco in Argentina and reveal distal and proximal drivers,53 analyzing them in both spatial and temporal models. We measured N2O emissions, soil54 and climate variables monthly in nine sites over two years. Mean annual temperature55 and the following soil properties: phosphorous availability, carbon:nitrogen ratio, clay56 and sand percentages were the main distal drivers controlling N2O emissions in the spatial model, while among proximal drivers, only soil nitrate contents were positively58 related to N2O emissions. When considering the seasonal variability of N2O emissions59 (temporal model), we found that emissions were positively related to proximal drivers,60 such as soil nitrate and soil temperature. Our results show that soil N2O emission drivers61 differ between spatial and temporal models in natural grasslands and forests, explaining62 up to 85% and 56% of variations in N2O emissions, respectively. Temperature increased63 N2O emissions in both spatial and temporal models, therefore future global warming64 may increase background emissions from natural ecosystems with important positive65 feedbacks on the earth system warming.