Ryan Sponseller

Phone: +46 76 81 69 705
Department of Ecology & Environmental Science, Umeå University

Demian Hauptmann

(Master's student)

April to June 2016, during my ERASMUS+ exchange to Umeå University, I got to spend two months in Abisko, when participating in the course “Arctic Geoecology”. As my personal interest in sustainability and climate change already grew before coming to Abisko, this was the perfect opportunity to combine both, my private interests and my research interests, in this hot topic. During my second visit to Abisko (late spring to beginning of autumn, 2018) I collected data for my Master's Thesis. 

My Master’s Thesis project focuses on Nutrient Limitation in Arctic Streams, more precise in Miellajokka catchment close to Abisko. Miellajokka catchment reaches from the headwaters up in the tundra (around 1000 m) down to groundwater fed streams in dense birch forest. Nutrient limitation is assessed by using nutrient diffusing substrata (NDS) with a 21 day deployment time to grow algae (biofilm). The biofilm is then incubated to measure gross primary production (GPP), community respiration (CR) and finally analysed for chlorophyll alpha (Chl a) using spectrometry. Data collection also includes stream chemistry at the day of installation and retrieval, as well as temperature and light using a continuous logger. To assess nutrient limitation, a temporal and spatial approach is used. This includes one site down in the birch forest of the Miellajokka catchment, with continuous deployment, starting in March and finishing in the end of September. The temporal approach incorporates a light gradient and different discharge regimes, i.e. changing water chemistry starting with ice-cover and ending in the last weeks of the vegetation period. The spatial deployment was conducted during peak biomass, starting mid July until the beginning of August. 20 sites were spread across the tundra (9 sites) and the birch forest (11 sites) with the goal to reach as much spatial variability, such as chemistry, temperature and velocity. The project is still going on…

Lapporten, 2018

Miellajokka, 2018