Not All Nitrogen is Created Equal: A Long-Term Study from a New England Salt Marsh

In a study published this week, scientists including MBL Ecosystems Center Director Anne Giblin reveal that different forms of nitrogen have different impacts on a salt marsh ecosystem. The study, conducted at the Plum Island Ecosystem LTER, argues that both the form and quantity of nitrogen influx to the coasts, and how these different forms of nitrogen mediate the balance between marsh carbon storage and loss, will be crucial for managing coastal wetlands as sea levels continue to rise. This article is provided by Northeastern University's Marine Science Center.

On the cover of this month’s issue of BioScience, the tranquil scene of an evening in the tidal marsh belies the complex biological interplay of nutrients and organisms found within. The impacts and mechanisms of nutrient enrichment in this coastal zone, particularly of nitrogen introduced by human activity, are well documented in literature — but a new study in December’s BioScience suggests that understanding the forms of nitrogen in the system is a missing piece of the coastal management puzzle.

*Photo: Cordgrass in a salt marsh at the Plum Island research site. Credit: David Johnson @DavidSamJohnson*

The study, led by Dr. Jennifer Bowen, Associate Professor and Associate Chair of the Northeastern’s Marine and Environmental Sciences Department, synthesizes a decade of research from her team and collaborators, focused on understanding human impacts on the structure and function of salt marsh systems. Dr. Bowen has long used the living labs of the Boston area coasts to examine how urban ecosystems and microbial communities influence biogeochemical cycling. Her latest work examines nitrogen forms and flows in the TIDE project, a long-term nutrient enrichment experiment led by co-author Linda Deegan of the Woodwell Climate Research Center that is based at the NSF supported Plum Island Long-Term Ecological Research site in northern Massachusetts. Co-author Anne Giblin of the Marine Biological Laboratory, Woods Hole, is lead principal investigator of the Plum Island research site.