Mercury accumulation in grass and forb species as a function of atmospheric carbon dioxide concentrations and mercury exposures in air and soil.

摘要: Abstract The goal of this study was to investigate the potential for atmospheric Hg° uptake by grassland species as a function different air and soil Hg exposures, specifically test how increasing CO 2 concentrations may influence foliar concentrations. Four common tallgrass prairie were germinated grown 7 months in environmentally controlled chambers using two elemental mercury (Hg°; 3.7 ± 2.0 10.2 ± 3.5 ng m −3 ), ( −1 carbon dioxide (CO ) (390 ± 18, 598 ± 22 μmol mol exposures. Species used included C4 grasses C3 forbs. Elevated led lower plants exposed low (i.e., ambient) concentrations, but no effect apparent at higher exposure. observed suggests that leaf might be physiological processes such stomatal conductance which is typically reduced under elevated . Foliar tissue had than those Hg°, only when also relationships exposures indicate these have limited capacity storage; ambient all absorption sites leaves been saturated while saturation reached Hg°. not correlated except one four (Rudbeckia hirta). Higher resulted high root considerably increased percentage total plant allocated roots. large shifts allocation patterns—notably conditions slightly above natural background levels—indicate potentially strong role belowground transformation cycling processes.