Methyl halide emissions from greenhouse‐grown mangroves

Abstract

[1] Two mangrove species, Avicennia germinans and Rhizophora mangle, were greenhouse grown for nearly 1.5 years from saplings. A single individual of each species was monitored for the emission of methyl halides from aerial tissue. During the first 240 days, salinity was incrementally increased with the addition of seawater, and was maintained between 18 and 28% for the duration of the study. Exponential growth occurred after 180 days. Methyl halide emissions normalized to leaf area were measured throughout the study and varied dramatically. Emission rates normalized to land area (mg m À2 y À1 ), assuming a LAI = 5, yielded 82 and 29 for CH 3 Cl, 10 and 1.6 for CH 3 Br, and 26 and 11 for CH 3 I, for A. germinans and R. mangle, respectively. From these preliminary determinations, only CH 3 I emissions emerge as being of possible global atmospheric significance. This study emphasizes the need for field studies of methyl halide emissions from mangrove forests.

Determination of chloromethane and dichloromethane in a tropical terrestrial mangrove forest in Brazil by measurements and modelling

“…Based on the present study the mangroves contribute 0.3 percent of CH 2 Cl 2 and 0.2 percent of CH 3 Cl in the global emission budget. This study corroborates the study by Manley et al (2007) which estimated that mangroves produce 0.3 percent of CH 3 Cl in the global emission budget. Although they contribute a small percentage in the global budget, their long lifetime enables them to contribute to the destruction of ozone in the stratosphere.…”

“…Our estimated values are thus lower to slightly lower than the laboratory measurements by Manley et al (2007). This suggests that we estimate a little less emission than the laboratory study.…”

“…The global mangrove area is slightly reduced at present (Giri et al, 2011) compared to the previous study by Duarte et al (2005). Manley et al (2007) used laboratory measurements of a single grown mangrove in a green house experiment data to up-scale the CH 3 Cl contribution. Using a global area of 2 × 10 5 km 2 , they estimated a CH 3 Cl emission of 12 Gg yr −1 .…”

“…Current estimate of the global total area of mangroves using recently available Global Land Survey (GLS) and the Landsat archives is 137,760 km 2 (Giri et al, 2011). Manley et al (2007) studied the methyl halide emissions from greenhouse-grown mangroves. They estimated a global annual release of CH 3 Cl from mangroves 12 Gg yr −1 .…”

Methyl chloride from the Aura Microwave Limb Sounder: First global climatology and assessment of variability in the upper troposphere and stratosphere

“…Warm tropical and subtropical open ocean and coastal waters, once thought to be the dominant source [e.g., Singh et al, 1983], are now estimated to contribute 11% to the global CH 3 Cl budget [e.g., Moore et al, 1996;Hu et al, 2010;Xiao et al, 2010]. Other minor sources include freshwater wetlands, peatbogs, coastal salt marshes, and mangroves [e.g., Varner et al, 1999;Rhew et al, 2000;Rhew and Mazéas, 2010;Dimmer et al, 2001;Manley et al, 2007;Hardacre et al, 2009]; flooded rice paddies [Redeker et al, 2000;Redeker and Cicerone, 2004]; wood-rotting fungi [Harper, 1985;Watling and Harper, 1998;Moore et al, 2005]; and fungus gardens cultivated by leaf cutter ants [Mead et al, 2008]. Atmospheric CH 3 Cl also arises through abiotic release from senescent and dead plant material and organic matter in soils and sediments (again primarily in tropical and subtropical regions) [e.g., Keppler et al, 2000Keppler et al, , 2005Hamilton et al, 2003].…”