Líffræðifélag Íslands
Líffræðiráðstefnan 2015
Erindi/veggspjald / Talk/poster V11
Steven Dauwe (1,2), Bjarni D. Sigurdsson (1), Ivan A. Janssens (2)
1. Agricultural University of Iceland 2. Universiteit Antwerpen
Kynnir / Presenter: Steven Dauwe
Tengiliður / Corresponding author: Steven Dauwe (steven.dauwe@uantwerpen.be)
A loss of 40 % soil carbon has recently been observed in Icelandic grasslands warmed naturally by 5-10 °C, a realistic temperature increase for northern latitudes within this century. The warming-induced increase in plant productivity could not compensate for this large C loss. This provides empirical support for a substantial source of CO2 in the near future, potentially accelerating climate change. My PhD aims to unravel the mechanisms behind this observed soil C loss by focusing on different soil C fluxes, the role of concurrent changes in nutrient availability, and whether or not the composition of the microbial community matters. Moreover, we aim to study how the ecosystem has adapted structurally (plant and microbial communities, soil bulk density) and functionally (productivity, carbon in- and effluxes, closed or open nitrogen cycle). To investigate whether observed responses are rather temperature driven (direct response) or nutrient driven (indirect response) a N gradient (+0, +5, +25, +50, +150 kg/ha.y) is set up alongside a T gradient (+0, +1, +3, +5, +10, +20 °C). The main advantage of these naturally warmed study sites are 1) that we cover the full warming gradient encompassed by the IPCC RCP scenario’s for the sub-arctic, allowing us to identify non-linear responses, and 2) the presence of short-term (7 years) and long-term (> 50 years) warmed plots to identify transient responses.