Evasion of mercury vapor from the surface of a recently limed acid forest lake in Sweden

Mercury is emitted from soil and water surfaces, but few actual direct flux measurements have been reported. During June, 1994 we performed the first micrometeorological measurements of Hg vapor fluxes over a boreal forest lake. Using highly precise methods with multiple replicate samplers, we measured concentration gradients of Hg vapor, CO₂ and H₂O over the lake surface. Mercury was readily emitted from the lake surface, and we found no evidence of Hg dry deposition to the lake. Emission rates over the lake averaged 8.5 ng m² h^?1, and appeared to be weakly influenced by water temperature and solar radiation. These fluxes were somewhat higher than those previously measured using surface chambers at this site.