Combined climate factors alleviate changes in gross soil nitrogen dynamics in heathlands

TY - JOUR

T1 - Combined climate factors alleviate changes in gross soil nitrogen dynamics in heathlands

AU - Bjorsne, Anna-Karin

AU - Rutting, Tobias

AU - Ambus, Per Lennart

PY - 2014/8/1

Y1 - 2014/8/1

N2 - The ongoing climate change affects biogeochemical cycling in terrestrial ecosystems, but the magnitude and direction of this impact is yet unclear. To shed further light on the climate change impact, we investigated alterations in the soil nitrogen (N) cycling in a Danish heathland after 5 years of exposure to three climate change factors, i.e. warming, elevated CO2 (eCO2) and summer drought, applied both in isolation and in combination. By conducting laboratory 15N tracing experiments we show that warming increased both gross N mineralization and nitrification rates. In contrast, gross nitrification was decreased by eCO2, an effect that was more pronounced when eCO2 was combined with warming and drought. Moreover, there was an interactive effect between the warming and CO2 treatment, especially for N mineralization: rates increased at warming alone but decreased at warming combined with eCO2. In the full treatment combination, simulating the predicted climate for the year 2075, gross N transformations were only moderately affected compared to control, suggesting a minor alteration of the N cycle due to climate change. Overall, our study confirms the importance of multifactorial field experiments for a better understanding of N cycling in a changing climate, which is a prerequisite for more reliable model predictions of ecosystems responses to climate change.

AB - The ongoing climate change affects biogeochemical cycling in terrestrial ecosystems, but the magnitude and direction of this impact is yet unclear. To shed further light on the climate change impact, we investigated alterations in the soil nitrogen (N) cycling in a Danish heathland after 5 years of exposure to three climate change factors, i.e. warming, elevated CO2 (eCO2) and summer drought, applied both in isolation and in combination. By conducting laboratory 15N tracing experiments we show that warming increased both gross N mineralization and nitrification rates. In contrast, gross nitrification was decreased by eCO2, an effect that was more pronounced when eCO2 was combined with warming and drought. Moreover, there was an interactive effect between the warming and CO2 treatment, especially for N mineralization: rates increased at warming alone but decreased at warming combined with eCO2. In the full treatment combination, simulating the predicted climate for the year 2075, gross N transformations were only moderately affected compared to control, suggesting a minor alteration of the N cycle due to climate change. Overall, our study confirms the importance of multifactorial field experiments for a better understanding of N cycling in a changing climate, which is a prerequisite for more reliable model predictions of ecosystems responses to climate change.

U2 - 10.1007/s10533-014-9990-1

DO - 10.1007/s10533-014-9990-1

M3 - Journal article

SN - 0168-2563

VL - 120

SP - 191

EP - 201

JO - Biogeochemistry

JF - Biogeochemistry

IS - 1-3

ER -