Pearl Mzobe
Doctoral student
Bearing the brunt of warming: Interactions between carbon and hydrology in northern Sweden
Author
Summary, in English
Climate modelling studies indicate that subarctic ecosystems are predicted to show some of the earliest responses to climate change. The predicted temperature and precipitation changes have implications for the carbon biogeochemical cycle with ancillary effects in permafrost soils, vegetation, and stream networks. Browning, a result of changes in dissolved organic carbon (DOC) export to river systems, has been marked as an early indicator of climate-induced changes in northern freshwaters. The release of DOC in to rivers and atmosphere has the potential to further increase the emissions of greenhouse gasses. The reintroduction of old carbon is not limited to atmospheric interactions as the lateral flux of carbon at the terrestrial-aquatic interface is further affected by warming. Parts of the subarctic region are host to permafrost soils, which serve as a store of frozen soil organic carbon. Climatic changes threaten to turn these regions from carbon sinks to carbon sources. Active layer deepening, a result of precipitation and temperature changes in permafrost zones, is a source of increasing greenhouse gas (CO2 and CH4) emissions. Changes in of permafrost areas spurs changes in catchment land cover and ecosystem function.
This study was conducted in a subarctic catchment with mixed vegetation cover and a permafrost thaw gradient to understand the spatio-temporal changes in the biogeochemical cycle. The Normalized Vegetation Difference Index (NDVI), together with easily available topographical indices, was used to model the DOC release into streams using GIS analysis and linear regression methods.
The results of this research show that DOC is concentrated in the low-lying areas of Stordalen catchment. The distribution of DOC was largely controlled by topographic factors, in particular slope and the presence of mires. This study points to a largely unexplored potential of using geospatial analysis methods to capture and represent responses to climate change. Applying geospatial techniques provides a first step spatio-temporal approach to present phase shifts in the broader scale of catchment carbon cycling.
This study was conducted in a subarctic catchment with mixed vegetation cover and a permafrost thaw gradient to understand the spatio-temporal changes in the biogeochemical cycle. The Normalized Vegetation Difference Index (NDVI), together with easily available topographical indices, was used to model the DOC release into streams using GIS analysis and linear regression methods.
The results of this research show that DOC is concentrated in the low-lying areas of Stordalen catchment. The distribution of DOC was largely controlled by topographic factors, in particular slope and the presence of mires. This study points to a largely unexplored potential of using geospatial analysis methods to capture and represent responses to climate change. Applying geospatial techniques provides a first step spatio-temporal approach to present phase shifts in the broader scale of catchment carbon cycling.
Department/s
- Dept of Physical Geography and Ecosystem Science
Publishing year
2021
Language
English
Document type
Dissertation
Publisher
Media-Tryck, Lund University, Sweden
Topic
- Earth and Related Environmental Sciences
Keywords
- dissoved organic carbon (DOC)
- carbon flux
- permafrost thaw
- hydrological connectivity
- GIS analysis
Status
Published
Supervisor
- Andreas Persson
- Martin Berggren
- Petter Pilesjö
ISBN/ISSN/Other
- ISBN: 978-91-89187-08-5
- ISBN: 978-91-89187-07-8
Defence date
9 September 2021
Defence time
15:00
Defence place
Pangea, Lund Join via zoom: https://lu-se.zoom.us/j/62094023285
Opponent
- Sally McIntyre (Professor)