51. Effects Of Elevated Atmospheric Co2 On Wetland Soils.
- Author
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Sun-Kee Hong, Lee, John A., Byung-Sun Ihm, Farina, Almo, Yowhan Son, Eun-Shik Kim, Jae Chun Choe, Seon-Young Kim, Hojeong Kang, and Freeman, Chris
- Abstract
Anthropogenic activities have increased the concentration of atmospheric CO2 from about 280 parts per million (ppm) at the beginning of the industrial revolution to 369 ppm at the present time. Future estimates of atmospheric CO2 concentration for the year 2050 range between 450 ppm and 600 ppm (Kattenburg et al. 1995). More than two decades of study on the effects of CO2 enrichment have greatly improved our understanding of plant response such as net primary productivity, species abundance, community composition and soil respiration (root plus microbial respiration) in terrestrial ecosystems (Poorter 1993, Curtis and Wang 1998, Ball and Drake 1998, Mooney et al. 1999, Edwards and Norby 1999, Zak et al. 2000). In addition, the chemical and physical composition of plant material and decomposability of plant litter have drawn much attention (Cotrufo et al. 1994, Cotrufo and Ineson 1995, King et al. 1997) Unlike the terrestrial ecosystem studies, however, relatively less effort has been made to elucidate possible effects of elevated CO2 on wetland ecosystems. Although wetland ecosystems including peat-forming wetland cover only 2-6 % of global land surface (Gorham 1991), they play a pivotal role in global biogeochemical cycles. Firstly, peat accumulation in peatland ecosystems over thousands of years has resulted in a vast store of carbon of 455 Pg C (Gorham 1991, Van Breemen 1995, Adams and Faure 1998). This represents 20-30% of the world's pool of soil organic carbon and is comparable to the total carbon in the atmosphere as CO2 (IPCC 1990). Secondly, wetlands are substantial sources of radiatively active trace gases such as CH4 and N2O (Freeman et al. 1993). For example, natural wetlands and rice paddies release about 40-50% of global emissions of CH4, which is 25 times more radiatively active than CO2 on a molar basis (Cicerone and Oremland 1988). As such, even small changes in net primary productivity or decomposition of soil organic matter by elevated CO2 could significantly influence the balance of greenhouse gas flux between the atmosphere and biosphere. This would greatly influence the future trajectory of global warming (Mitchell et al. 2002). However, little is known about how C and N dynamics on wetland ecosystems will respond to elevated CO2 conditions. In particular, below ground processes in wetland ecosystem are scarcely reported. The aim of this review is to organize existing knowledge about the effects of elevated CO2 on wetland ecosystems. In particular, we would like to address the issue of how wetland ecosystems will respond to elevated CO2 conditions and whether these responses may cause feedbacks to further global climate change. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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