Marine Biological Laboratory senior scientist Anne Giblin is working with a team of scientists on a study that aims to reconcile conflicting findings on the impacts of excess nitrogen on marshes.

Dr. Giblin explained that past studies where people have added nitrogen to salt marshes have led to enhanced plant growth and accretion of sediments. Accretion is a natural process in marshes where sediments accumulate, raising the marsh’s vertical height. Enhanced accretion is beneficial because it allows a marsh to rise faster than local sea levels.

However, there is also evidence pointing to nitrogen’s negative effects on marshes. Dr. Giblin explained that other studies have shown nitrogen to decrease the strength of salt marsh soils and increase decomposition of sediment. Dr. Giblin said that the changes cause marshes to weaken.

Those results seem to be contradictory, but Dr. Giblin has a hypothesis that the contradiction is caused by differences in the forms of nitrogen used in the studies. Nitrogen takes several forms throughout the nitrogen cycle, such as nitrates, nitrites and ammonium. Those different forms may have varied impacts on marshes, Dr. Giblin said. Read the full story...

Source: Falmouth Scientist To Conduct Nitrogen Study With Collaborators | The Falmouth Enterprise