Morphing Manganese in Oceans Reveal Chemistry of the Environment

It turns out that manganese is far more prevalent in ocean environments than previously thought. Scientists have discovered that this element, critical to many life processes, moves through the natural world in ways that they didn't expect.

"You wouldn't think manganese is that important, but without manganese, we wouldn't have the molecular oxygen that we breathe," said George Luther, the co-author of the new study, in a news release.

Manganese is present in the environment in three different forms. There's manganese (II), manganese (III) and manganese (IV). These different forms are related to the oxidation state, or number of electrons present. It's the second most common metal in Earth's crust and changes between oxidation states while reacting with other elements in the environment.

In order to better understand the movement of manganese through the oceans, the researchers took samples from the largest estuary in the world, the Gulf of Saint Lawrence off the southeast of Canada. These sediment samples were then analyzed using a new technique to differentiate between manganese forms.

In the end, the scientists found that manganese (III) comprised up to 90 percent of the total manganese present in the sites sampled. This, in particular, was surprising since it was thought that manganese (II) and manganese (IV) were the dominant forms in aquatic environments.

So what does this tell the researchers? It helps explain anomalies in manganese models that have puzzled scientists in the past. The findings could also shed light on the complex connections between biology, geology and chemistry in ocean environments.

The findings are published in the journal Science.