Nitrogen uptake patterns by snow addition in a sub-Arctic dry heath tundra ecosystem

• Main Author: Montañez Medina, Kimberly
• Format: Other/Unknown Material
• Language: English
• Published: Lunds universitet/Institutionen för naturgeografi och ekosystemvetenskap 2023
• Subjects: Arctic ecosystem; snow accumulation; growing season length; nutrient availability; carbon sequestration; greenhouse gas emissions; climate change impacts; CoupModel; Environmental Changes at Higher Latitudes (EnCHiL); Earth and Environmental Sciences; Arctic; Vallas; Climate change; Tundra
• Online Access: http://lup.lub.lu.se/student-papers/record/9129380

The Arctic heath tundra ecosystem is undergoing rapid transformations driven by climate change, which particularly affects snow accumulation and the length of the growing season. In this study, I examined the influence of snow depth on parameters such as water content, soil temperature, microbial activity, and nutrient availability and investigated their implications for plant water availability and nitrogen cycling processes. Through snow fence experiments and 15N isotope labelling and simulations of carbon fluxes with the CoupModel, I found that a longer growing season positively impacted plant productivity, carbon accumulation, and nutrient assimilation. Both evergreen and deciduous plants benefited from an extended growing season, but when the growing season was shortened, evergreen species exhibited greater resilience, while deciduous species were more susceptible to detrimental effects on growth and photosynthesis. Non-growing season alterations in snow cover could have intricate consequences on annual photosynthesis and greenhouse gas emissions, as increased snow depth favored microbial activity in winter and resulted in higher carbon dioxide emissions. These emissions counteracted the carbon sequestration advantages of the growing season, underscoring the importance of considering both the duration of the growing season and snow dynamics in conservation and management strategies. El ecosistema de tundra ártica experimenta cambios rápidos debido al cambio climático, especialmente en la acumulación de nieve y la duración de la temporada de crecimiento. Este estudio investigó los impactos de la profundidad de nieve en parámetros clave, como el contenido de agua, la temperatura del suelo, la actividad microbiana y la disponibilidad de nutrientes, y sus efectos subsiguientes en la disponibilidad de agua para las plantas y los procesos de ciclado de nitrógeno. A través de experimentos con vallas de nieve y etiquetado con el isotopo 15N y simulaciones de flujos de carbono con el modelo CoupModel, se determinó ...