LSU researchers received a $1.4 million grant to study the impact severe weather disturbances have on the western portion of the Gulf of Mexico.
Z. George Xue, an associate professor in LSU’s Department of Oceanography and Coastal Sciences, is leading the research of the project, along with colleagues from LSU, Texas and East Carolina University. Their research will focus on ecosystem resistance and resilience after severe weather disturbances.

Xue said that it’s difficult to define whether an ecosystem has a high resilience level because of its complexity. He said there are many components such as wetlands, marshes and coastal water, but the resistance and resilience of these different ecosystems are what they want to learn about.

While they are still trying to learn more about each ecosystem, they can tell that some have a higher resilience than others because of hurricanes, Xue said. Marshes and mangroves will be easily submerged by water if there is a hurricane, causing their vegetation to be destroyed and potentially taking years to recover. 

On the other hand, estuaries have a shorter recovery time. An estuary is a body of water and the exchange of its water with coastal ocean water is much faster than the exchange of water on land. 

“It might take a shorter time for estuaries to recover compared to wetlands or marshes,” Xue said.

Xue also said that when looking at the direct impact of the food chain in the ecosystem, it’s obvious the waves and currents are very strong, causing violent conditions in the ocean. The water column is constantly remixing and changing drastically, so the pollutants in the shallow water soil will be disrupted and released back into the water system. This could affect the food chain because the pollutants harm the animals in the ecosystem. 
Xue said other impacts are debris from the land, causing estuaries to have high turbidity in the water. High turbidity lowers the amount of sunlight in the water, creating less plant growth which results in less oxygen available to the animals in the water. 

“What effect that the land sources will have on the ocean ecosystem is also a big question mark,” Xue said.

Xue and his scientists will be working at three different sites between Louisiana and Texas including Barataria Bay in Louisiana, Galveston Bay in Texas and  Mission-Aransas Estuary in Texas. 

He said the setup is different in each area because Louisiana’s Barataria Bay is very humid and subtropical. Galveston Bay is much drier than the bay and urbanized, and Mission-Aransas Estuary is semi-arid and has limited freshwater input, resulting in salinity double that of the ocean’s. 

Xue said for the research, the team is using a state-of-the-art community model system called the Regional Ocean Modeling System, or ROMS. This model will help them navigate the physics of the ocean. It can also be used as a land surface model to simulate the movement of the ocean on the land.

Xue said they run both of these systems simultaneously, called a cuphold system, allowing the ocean and the land to communicate with each other. The relationship between the land and the ocean is ongoing, and these scientists are attempting to gain a better understanding of it. 

“This model is very effective as we have already applied it to another hurricane in the past,” Xue said.
Xue said he found this new technique has largely improved the accuracy of models simulated sea level variation. He believes this new technique can help improve past research.  This project will be viewed from a previous NASA project using a similar method.

Oceanography and Coastal Sciences professor Kanchan Maiti said the team’s research is devoted to understanding and scientifically modeling the impact of unpredictable events, such as hurricanes and floods, on the ecosystem. 

As of now, most of the global models don’t incorporate the impact of these unpredictable events, so it’s unclear what the full effect is on the environment, Maiti said.  He said that this project spans Louisiana to Corpus Christi, Texas, to fully understand how these coastal systems are affected. 

He said that the group’s research is focused mostly on carbon as carbon can change an ocean’s acidity and increase carbon dioxide in the atmosphere. 

“Especially in Louisiana, carbon dioxide is more prominent because all the wetland soils have between 10-20% organic carbon in them,” Maiti said. 
Hurricanes often result in land loss, meaning the carbon from these wetlands is either released into the atmosphere or dissolved in the ocean. This can hurt the ecosystem because it changes the water chemistry and negatively impacts the survival of the organisms living in it. These samples are collected after a big tropical storm or hurricane hits. 

“Then we try to understand how the carbon flow is happening in the system during these events and how long the system takes to come back to its original form,” Maiti said. 

Maiti said the ROMS model creates a mesh of the entire Gulf of Mexico. The model runs through every part of the gulf, figuring out where currents are happening and giving the scientists a solution to the problem. 

Maiti said that his prediction for the differences between the Louisiana and Texas sites are that Western Texas will be very arid and have less carbon stored in its wetlands than Louisiana. There will be a bigger change in carbon number in Louisiana than Texas.