Líffræðifélag Íslands
Líffræðiráðstefnan 2015

Erindi/veggspjald / Talk/poster V12

The ForHot experiment: Effects of natural soil warming gradients on ecosystem structure and function

Bjarni D. Sigurdsson (1), Edda S. Oddsdottir (2), Theodóra Ragnarsdóttir (1), Brynhildur Bjarnadóttir (3), Ivika Ostonen (4), Krassimira Ilieva-Makulec (5), Christian Körner (6), Niki Leblans (1, 7), Steven Dauwe (1,7), Ivan A. Janssens (7)

"1) Landbúnaðarháskóli Íslands; 2) Rannsóknastöð skógræktar - Mógilsá; 3) Háskólinn á Akureyri, 4) Tartu Univ., Eistlandi; 5) Card. St. Wyschynski Univ., Póllandi; 6) Univ. Basel, Sviss; 7) Univ. Antwerp, Belgíu"

Kynnir / Presenter: Bjarni D. Sigurðsson

Tengiliður / Corresponding author: Bjarni D. Sigurdsson (bjarni@lbhi.is)

On May 29, 2008, there was an earthquake in Iceland that measured 6.3 on the Richter scale. One of its implications was that geothermal systems were disturbed and moved to a new and previously “cold” areas, which increased soil temperature (Ts) at 10 cm depth from +0 °C to +50 °C under both grasslands and planted forest ecosystems. The ForHot pilot project started in 2011, following the ESF-CLIMMANI meeting in Iceland, where participants visited the forest site. By 2014 the ForHot experiment has grown into a large-scale ecosystem study, where three ecosystems are being studied (Grasslands with short- and long-term geothermal warming and a Sitka spruce plantation with short-term warming), involving 19 researchers and 13 students. The experimental setup consists of five transects in each ecosystem, each with six permanent plots at ca. Ts +0 (unwarmed control), +1, +3, +5, +10 and +20 °C Ts. The most unique features of the ForHot experiment are: I. Large temperature gradients within a smaller area allow us to identify ecosystem thresholds in responses to warming. II. Two contrasting ecosystems, planted forest vs. grasslands allow us to look at ecosystem differences. III. Two similar grasslands with different warming history. One with short-term warming (6 years) and another in a near-by area (<3 km) where soil warming was not disturbed by the 2008 earthquake. This allows us to derive some temporal aspects in responses to warming The ForHot experiment, with its natural soil temperature gradients, gives an opportunity to study how various ecosystem processes are affected by soil temperature. It is not a prefect simulation of climate change, since the warming only comes from below, but in this system we are able to test our mechanistic understanding of how different plant and soil processes are affected by soil warming.