Global vs local patterns of N2O and CH4 emissions and regulating factors in peatlands

Ülo Mander1, Jaan Pärn1, Teele Ligi1, Marika Truu1, Jaak Truu1, Sergey Egorov1, Järvi Järveoja1, Christina Vohla1, Martin Maddison1, Kaido Soosaar1, Kristjan Oopkaup1, Alar Teemusk1, Jens-Konrad Preem1, Evelyn Uuemaa1, Kuno Kasak1, Anto Aasa1, Ivika Ostonen1
1 Dept. Geography, University of Tartu

Invited Talk 6 in Biogeochemistry of wetlands

15.07.2014, 10:00-10:30, H17

This study is aimed to analyse relationships between the environmental factors and the spatial distribution of the main functional genes nirS, nirK, and nosZ regulating the denitrification process. Also, additional analysis is conducted on the relationships between the intensity of CH4 emissions and methanogenesis regulating functional genes mcrA, pmoA, and dsrAB.

Variations in hydrological regime, soil temperature and peat quality have been taken into the consideration at both local and global scale. Measurements of greenhouse gas (GHG) emissions using static chambers, groundwater analysis, gas and peat sampling for further laboratory analysis has been conducted in 20 study sites in various peatlands in Iceland (2011), Romania (2012), Santa Catarina/Brazil (2012), Quebec/Canada (2012), Bashkortostan/Russian Federation (2012), Sichuan/China (2012), Estonia (2012), Florida/USA (2013), France (2013), West Siberia/Russia (2013), Uganda (2013), French Guyana (2013), Tasmania (2014) and New Zealand (2014). In each study area at least 2 transects along the groundwater depth gradient, one preferably in undisturbed, another one in drained area, and at least three rows of sampling sites (3-5 replicate chambers and one piezometer and soil sampling plot in each) in both has been established for studies. In each transect GHG emission was measured during 2-3 days in at least 5 sessions.  In addition, organic sediments from the created riverine wetlands in Ohio/USA in 2009 and relevant gas emission studies have been used in the analyses (Ligi et al 2014a,b Ecol Eng). In the laboratories of Estonian University of Life Sciences and the University of Tartu, the peat chemical quality (pH, N, P, C, NH4, NO3, Ca, K, Mg, S) and N2O, CO2, and CH4 concentration in gas samples (50mL glass bottles and exetainers) were analysed. The peat samples for further pyrosequencing and qPCR analyses are stored in fridge by  -22oC.

This presentation will consider the variation of GHG emissions and hydrological conditions in the study sites.  In addition, several selected biophysical factors will be taken into account. Based on the preliminary results we can conclude that the relationship between the environmental factors and gas emissions show similar patterns at both local and global scales. 

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last modified 2014-02-13