Emissions of anaerobically produced methane by trees

Abstract

[1] Recent studies indicate that plants may be a previously overlooked but significant source of atmospheric CH 4 , though there is considerable disagreement on the mechanism of production. Our work sought to verify that woody deciduous trees grown under inundated conditions had the capacity for transporting CH 4 from an anaerobic subsurface to the atmosphere and to consider if such a source could be important globally. Here, we report results from a greenhouse mesocosm study that indicate significant emissions of anaerobically produced CH 4 transmitted to the atmosphere through broadleaf riparian tree species grown under flooded conditions. Using a leaf area normalized mean emission rate (0.7 ± 0.3 mg cm −2 hr −1 ), results were scaled globally for flooded forest regions and estimated to be 60 ± 20 Tg year −1 , ∼10% of the global CH 4 source. The carbon isotopic composition of CH 4 emitted was found to be significantly enriched compared with expectations (d 13 C ∼ −54‰) and provided an important isotopic constraint on the global source which coincides with the mean of the globally scaled greenhouse-based estimate. Citation: Rice, A.

Methane transport and emissions from soil as affected by water table and vascular plants

“…Contrary to several studies in which plants were found to increase CH 4 emissions, we found that mesocosms with plants emitted similar or even lower amounts of CH 4 than those with bare soil [11,13,22,40,46,47]. Although, some species (e.g.…”

Influence of Different Plant Species on Methane Emissions from Soil in a Restored Swiss Wetland

“…In an earlier study, we showed that graminoids tended to transport more methane from rhizosphere to atmosphere than forbs [13], [14], and other workers have also found plant growth form or functional type to be a factor influencing methane emissions from wetlands [15]–[17]. However, most of this information has come from mesocosm experiments, and field studies and needs to confirm whether the observed differences are ecologically important.…”

Effect of plant species richness on methane fluxes and associated microbial processes in wetland microcosms

“…Constructed wetlands (CWs), a natural alternative to technological methods of wastewater treatment, have been widely used Christensen, 2001;van der Gon and Neue, 1996); (2) A wide range of labile carbon compounds, including organic acids, sugars, and amino acids, are released into the root zones through plant root systems, stimulating methanogens and their activities (Bais et al, 2006;Bertin et al, 2003;Ström et al, 2005); (3) Aquatic plants can mediate the transport of CH 4 emission from wetlands through aerenchyma, increasing the net CH 4 emission in the environment (Morin et al, 2014;Rice et al, 2010;Rusch and Rennenberg, 1998); (4) Some plants themselves can emit CH 4 under aerobic (Bruhn et al, 2012;Keppler et al, 2008Keppler et al, , 2009Wishkerman et al, 2011) or anaerobic conditions (Rice et al, 2010;Wang et al, 2011). The presence of plants may reduce (Maltais-Landry et al, 2009) or increase CH 4 emissions in the CW units.…”