Speakers at the Arctic seminar
The seminar on 21 October 2017 highlights natural science research at Umeå University with the help of three speakers. John Anderson, holder of the H.M. King Carl XVI Gustaf Professorship of Environmental Science 2017-18, and expert on Arctic climate issues. Also, Jonatan Klaminder and Ellen Dorrepaal, both senior lecturers at the Department of Ecology and Environmental Health. The seminar is held in English.
Setting Arctic environmental change in a global context
The Arctic is changing rapidly under pressure from increasing temperatures and other stressors, such as atmospheric pollution. It is therefore necessary to take a more holistic perspective of recent change and also see the Arctic in its global context. I will illustrate some of the key processes by reference to our work in south-west Greenland and their relevance for understanding future changes.
Worming of the Arctic (svensk titel: Nedmaskningen av Arktis)
Did you learn that earthworms are positive for the environment? If so, you are not alone. However, if you had grown up in arctic countries, such as USA and Canada, you might have learned that earthworms are considered a threat in many environments. In these countries it is now well established that earthworms spread by humans are re-engineering formerly glaciated forests with dramatic ecological consequences. In this presentation, I will show that Earthworms are currently radiating out in high numbers in arctic environments from cabin yards, abandoned farms and experimental research stations, or are directly released by fishermen, even within the most protected alpine National Parks. Their high biomasses, known negative impacts in other ecosystems, and persistence once established makes us suggest that non-native earthworm invasion may pose a potent threat to the most protected arctic environment in Northern Europe.
Cryoecology: how arctic ecosystems matter for our changing climate
Arctic tundra are the coldest ecosystems of our planet and have long acted as cooling elements for our climate. This is because treeless, snow-covered tundra strongly reflects incoming solar radiation, and because storage of large amounts of organic carbon in permanently frozen soils (permafrost) has long reduced greenhouse gas concentrations in the atmosphere. Above-average climate warming and changes in snow cover in the north will likely change this, by stimulating tree establishment in the tundra and by accelerating microbial breakdown of carbon in thawing permafrost. The rate of these changes is, however, highly uncertain, because treeline shifts and permafrost carbon losses are not only controlled by climate but also by ecological processes, which are still poorly understood. In this lecture, I will explain how interactions among plants and between plants and soil-microbes regulate the responses of treeline and permafrost ecosystems to climate change and thus their feedback to our climate.