DOCS Masters Student Wins Presentation Award for Mangrove Research

BATON ROUGE  - Nico Lonergan is researching the short-term impacts of TLP, or thin layer placement, a popular marsh restoration technique, on black mangrove marsh.

It’s specific field of inquiry, but one with a potentially significant impact, as it sits at the intersection of the many changes taking place on the Louisiana coast – the area’s well known coastal land loss and the accompanying restoration efforts, the warming winters that are allowing the black mangroves to encroach northward, even the rising sea levels that are impacting not just Louisiana, but coastlines around the world.

Lonergan, who works in the Wetland Aquatic Biogeochemistry Laboratory with Oceanography & Coastal Sciences Professor John White, recently won first place in the student presentation division at the Wetland Soils Division of the recent Soil Scientists Society of America, when he presented this research.     

“I’m really honored to receive this award. For me, it highlights how critical it is to understand restoration tools like thin-layer placement, especially as Louisiana’s coast faces rapid environmental change. Knowing that my research can help inform ongoing efforts to protect our wetlands, and the communities that depend on them, is incredibly rewarding,” said Lonergan.

“Congratulations to Nico on this well-deserved recognition,” said White. “Just as it is important to conduct novel, rigorous science, science communication is equally important.  Nico did an excellent job conveying the need and the uniqueness of his research study, linking how this work helps humanity manage and adjust to such a dynamic coastal zone.”

Overall, Lonergan’s work bears good news for Louisiana’s troubled coast. It demonstrates that TLP, where a thin layer of sediment is placed on the surface of a marsh to raise its elevation and help it evade rising seas, has little impact on the mangroves’ ability to retain carbon or improve water quality, two important functions of the existing marshes.

His results show that, in the short term, mangrove soils hold more carbon than other types of marsh and that there is no difference in nitrogen and phosphorus dynamics.

To determine this, Lonergan collected marsh soil cores from Port Fourchon, an area where black mangrove and salt marsh co-exist. In the lab, he applied a thin layer of sediment to the cores and immediately began observing changes, looking for things like sedimentary thickness, oxygen availability, vegetation type and nutrient cycling processes like denitrification and phosphorus flux.  

He said he wanted to start monitoring immediately because not as much is known about the short-term impacts of things like TLP. “We want to see what's going to happen immediately after you place something... Are we going to have an immediate effect on marshes or immediate effect on mangroves?”

The next step is to try to recreate the TLP experiment in the marsh, where conditions can be monitored over the longer term.