My interest is the Ocean’s cycling of trace element mercury, and in particular, which factors and conditions drive the microbes to produce its most toxic organic form, the monomethylmercury. This needs an interdisciplinary approach; combining passive and active sampling techniques, methods of analytical chemistry, understanding the structure of microbial community and their metabolism; all of these wrapped in the physico-chemical realm of the ocean.
As mercury’s cycle is intimately connected with carbon cycling, redox state and oxygen concentration in the seawater, the variations in these will likely be reflected in the cycling of mercury. In the globally changing Ocean, the fate of mercury is unclear and it’s both challenging and important to understand the pathways of its biogeochemical transformations in order to avoid or mitigate the possible adverse effect.

Project title:

Methylation of labile mercury inorganic fraction in marine environment

Project summary:

We are following mercury (Hg) distribution and transformation in marine environments to determine where and under what conditions is inorganic Hg preferentially methylated to its organic species, monomethyl mercury (MeHg). Our focus is the labile fraction of total water concentrations, which is prone to bioaccumulation; a property of Hg that makes it particularly dangerous to ecosystem and human health. Because the relevant concentrations are usually below femtomolar, we use an extremely sensitive technique for pre-concentration; diffusive gradient in thin films (DGT). The distribution and occurrence of Hg species, along with supporting oceanographic data, may help to elucidate the natural circumstances that lead to formation of MeHg.

Field sites:

Belgian Coastal Zone (North Sea, Belgium)


mercury, methylmercury, DGT


Prof. Yue Gao