Reactive Nitrogenous Gas (Nitrous Acid) Emissions Along the Fen-Bog Gradient From Southern Boreal in Finland to Subarctic Peatland in the Context of Changing Climatic Conditions.

REACTIVE NITROGENOUS GAS (NITROUS ACID) EMISSIONS ALONG THE FEN-BOG GRADIENT FROM SOUTHERN BOREAL IN FINLAND TO SUBARCTIC PEATLAND IN THE CONTEXT OF CHANGING CLIMATIC CONDITIONS.

KHALING ELIEZER, TALLBACKA SAARA, ROVAMO MIRKKA, GIL LUGO JENIE, and MALJANEN MARJA.
Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio Campus, Yliopistonranta 1, 70210 Kuopio, Finland.
Keywords: Biogeochemical, changing climate, edaphic factors, HONO, Northern peatlands, Reactive nitrogen gas.


Peatlands are integral ecosystems within the global nitrogen cycle, and understanding their role in reactive nitrogen gas emissions, particularly nitrous acid (HONO) gas, is crucial for assessing their impact on atmospheric chemistry and climate change (Bhattarai et al., 2022 and Wang et al.,2023). Allocating HONO emissions from high latitude regions amidst evolving environmental conditions can mitigate current uncertainties in regional and global nitrogen budgets.
This study investigates potential HONO emissions across the fen-bog gradient in peatlands, ranging from southern boreal in Finland to the arctic and permafrost zone in northern Sweden. The study combines in-situ sampling of pristine soil cores with controlled laboratory analyses. HONO emissions were quantified using a dynamic chamber system integrated with a long path absorption photometer (LOPAP) analyzer. In addition, an analysis of the physicochemical properties of the soil was conducted to elucidate the potential factors influencing HONO emissions in peatland soils.
Preliminary findings suggest HONO emissions are subject to an intricate interplay of biogeochemical factors leading to significant variations in emission rates. Notably, the research result highlights the importance of moisture content and temperature variation, and vegetation composition in controlling HONO production and release. This ongoing research effort underscores the need for region-specific approaches in addressing the impact of peatlands on atmospheric chemistry.

Acknowledgement:
This work was supported by grant from Academy of Finland (decision nos. 348571)

References:
Bhattarai et al., (2022) Emissions of atmospherically reactive gases nitrous acid and nitric oxide from Arctic permafrost peatlands. Environ. Res. Lett. 17, 024034. doi: 10.1088/1748-9326/ac4f8e.
Wang et al., (2023). Large contribution of nitrous acid to soil-emitted reactive oxidized nitrogen and its effect on air quality. Environ. Sci. & Technol. 57 (9), 3516-3526. doi: 10.1021/acs.est.2c07793