主讲人简介:

Main interest in the biogeochemistry of carbon, nitrogen and trace elements in terrestrial ecosystems, including soil-water and soil- atmosphere (GHG) interactions, and impacts of environmental change (climate, land-use). Project leader Sino-Norwegian research projects on N2O emissions from sub-tropical forest (e.g. Larssen et al., 2011; Zhu et al., 2012). PI of projects on effects of grazing on C and N in alpine soils (Martinsen et al., 2011). Since the 1980’s, PI of several projects on soil acidification and Al chemistry (e.g. Mulder et al., 1989; de Wit et al., 2010), as well as the chemistry of trace elements (e.g. Almås et al., 2005; Okkenhaug et al., 2012). Recently, project leader and PI investigating management of soil quality (e.g. use of biochar in tropical crop production (Cornelissen et al., 2013); Effects of trees on soil properties in silviculture, Poland (Gruba & Mulder, 2008, 2013)).

讲座简介:

Due to increased emission of nitrogen oxides (from fossil fuel burning) and ammonia (from intensification in agriculture) during the last century, the annual input of reactive nitrogen into the global biosphere has more than doubled. Increased nitrogen inputs not only occur in agroecosystems, but also in forests due to elevated atmogenic deposition, as reported initially for North America and Europe. Recently, sub-tropical forests in eastern and southern China were identified as a third global hotspot for elevated deposition of atmogenic, reactive nitrogen, causing large scale nitrogen saturation. Recent studies in sub-tropical forests of S China suggest however, that, despite nitrogen saturation, the leaching of nitrogen with stream water is limited suggesting significant, yet unaccounted nitrogen sinks. In a detailed study in the nitrogen-saturated TieShanPing forested catchment, just outside Chingqing city, we show that gaseous emission of nitrogen, including N2O, an important greenhouse gas, maybe the dominant nitrogen sink. Our research indicates that the nitrogen-saturated subtropical forest at TieShanPing is a significant secondary source of N2O with an annual emission amounting to nearly 10% of the input of reactive atmogenic N.