How can methylmercury in the ocean be reabsorbed into the atmosphere?

Question

The Sacramento Bee news article Toxic fog may be poisoning some of California’s mountain lions, study says says

Algae in the ocean convert mercury to methylmercury, its most toxic form, which can be reabsorbed into the atmosphere and come ashore as marine fog, the release says.

Methylmercury [CH₃Hg]⁺ is an ion with an atomic mass well over 200. I don't think that it would readily evaporate, so how can it be reabsorbed into the atmosphere?

Answer 1

Much of the methyl mercury that enters the atmosphere may be dimethyl mercury, $\text{(CH}_3\text{)}_2\text{Hg}$. This is a very volatile compound which, if it were pure, would have 50 mm mercury or more vapor pressure at 20°C. Complexes involving more electronegative ligands, such as the chloride $\text{CH}_3\text{HgCl}$, are significantly less volatile, but still have more vapor pressure than purely inorganic mercury compounds.