In Summer 2015, postdoctoral fellow Paul Gauthier and undergraduates Olivia Trase ’17 (EEB) and Joseph Redmond ’18 (CBE) spent several weeks doing fieldwork in Abisko National Park in the region of Lake Torneträsk in Sweden. The group stayed at Abisko Scientific Research Station (ANS). This station is a facility of the Royal Swedish Academy of Sciences but managed by the Swedish Infrastucture for Ecosystem Science (SITES). The station is located 200 km north of the Arctic Circle in the upper part of the subalpine birch belt. The team collected data and samples for understanding the physiological and metabolic adaptations of mountain birches to the harsh Arctic weather. The results will help us understand the response of Arctic ecosystems to climate change.
Funded by a combination of sources, including Princeton Environmental Institute Grand Challenges, The Carbon Mitigation Initiative, and the Department of Geosciences, Gauthier is seeking to better understand how continuous daylight in the summertime at high latitudes influences net ecosystem productivity. Net ecosystem productivity is the difference between the uptake of CO2 by photosynthesis, and the release of CO2 by respiration. In order to predict the impact of climate change on the productivity of arctic ecosystems, a better mechanistic understanding of photosynthesis and respiration is required. Past studies have shown that the rate of respiration in leaves during the day is lower than the rate at night. It is still unclear why plants respire more in the dark, and there may be several causes. At high latitude, in the summer, several weeks pass when there is no darkness. Plants may have developed specific physiological and metabolic adaptations to thrive under those conditions. Understanding these adaptations could help improve the modeling of net ecosystem productivity at high latitude.
Gauthier also worked in Sweden in July 2014, with undergraduates Atleigh Forden ’16 (GEO) and Jacob Eisenberg ’16 (ORFE). During the second week of this 2014 trip, the average temperature was as high as 30°C (86°F), and precipitation was very low. In summer 2015, over 6 weeks of fieldwork, the average temperature was 7°C (45°F) with much higher precipitation. Our observations thus span weather extremes at the study site. The group is now working on implementing their data into local ecosystem models to evaluate the consequence of large temperature excursions on net ecosystem productivity for the subalpine birch belt.