Mercury stable isotopes constrain atmospheric pathways to the ocean
Mercury is one of the least concentrated trace elements in the ocean. Yet, the small seawater Hg levels biomagnify million times along the marine food chain, to reach harmful levels in predatory fish and their human consumers. Natural and anthropogenic Hg sources to the ocean remain ill-constrained. It took 10 years of development to come up with a method to measure Hg stable isotopes of seawater at subpicomolar levels.