Shihab Hossain Saran mingled amongst the crowd of marine scientists and engineers from across the world who packed the busy floor of the Mississippi Coast Coliseum and Convention Center on Sept. 28, 2023, the final day of last year’s OCEANS conference, Saran and the crowd around him had moved into an open area away from the event’s many booths and tables, and they listened together as an officiator was announcing the winners for the conference’s poster competition.
After judges announced the third- and second-place winners, Saran counted himself out. Comparing the numerical models on his poster to the notably different displays of the engineers comprising the other conference attendees, Saran did not feel at that moment that the grand prize was something he would earn. Nevertheless, when the officiator of the award ceremony announced first place, Saran heard his own name echoing from the convention center walls.
“Really, it was one of the most surprising and inspirational moments of my life,” Saran said. “Out of nowhere, I was the champion.”
Saran, who is a graduate assistant at Stennis Space Center and recently received his master’s degree in marine science, used his award-winning poster as an opportunity to display early research for his master’s thesis. In this poster, Saran assesses the efficacy of various salinity modeling configurations and stresses the importance of “accurate salinity and temperature estimates … around proposed experimental oyster reef locations” for properly rehabilitating oyster populations in the Mississippi Sound. The U.S. Army Corps of Engineers funded these restoration efforts and enlisted researchers from the University of Southern Mississippi in response to a series of extreme freshwater inflow events (such as Hurricane Katrina, the Deepwater Horizon oil spill and continued openings of the Bonnet Carré spillway) that have made the conditions of the Mississippi Sound increasingly hostile to its native populations.
Restoring the conditions of the Mississippi Sound is not an easy task. The restoration effort is a multi-stage project consisting of researchers and engineers who have various specializations. Many of these researchers, including Saran, are graduate students at the University of Southern Mississippi Gulf Park Campus in Long Beach, Miss.
Saran’s role in this project is to employ hydrodynamic modeling, a method that uses numerical models to develop realistic scenarios that will eventually help researchers understand the changing conditions of the Mississippi Sound. Saran’s utilizes the Regional Ocean Modeling System, to assess the temperature and salinity changes of the Mississippi Sound under extreme freshwater inflow conditions.
Saran began his academic career at the Bangladesh University of Engineering and Technology—one of the country’s leading engineering universities—where he studied water-resource engineering. During that time, Saran began to work with numerical models that attempted to predict how salinity levels would change in relationship to changing river-discharge conditions. These numerical models would serve as the theoretical foundation for Saran’s thesis research at USM and were a major motivation for his decision to pursue higher education in the United States
He applied to the University of Southern Mississippi’s Gulf Coast Campus after hearing of the university from a Facebook community of Bangladeshi students pursuing higher education in the United States, Canada, Europe, and Australia. He was drawn to USM in particular due to research specializations of the professors who now serve on Saran’s research committee: Dr. Mustafa Kemal Cambazoglu and Dr. Jerry Wiggert. These professors both conduct modeling research on the Gulf Coast, so Saran applied to be a part of their research group as a graduate student.
Cambazoglu, who has worked at the Stennis Naval Research Lab since 2009 and is now Saran’s thesis committee chair, recalls receiving Saran’s application to the program. Just as Saran was attracted to USM’s graduate program for its faculty’s specializations, Cambazoglu saw Saran’s history working with numerical models and knew he would be a good fit for this particular project.
“He was a very strong candidate,” Cambazoglu said. “We were very confident that he would be able to take on this task of learning a new model (ROMS) and then applying that new model for this project.”
High Sea Levels Cause Coastal Flooding
Saran has consistently challenged himself across the span of his academic career. As a water-systems engineer who focuses his research on coastal and near-coastal regions, Saran has chosen a research subject that even his committee chair acknowledged as being “challenging in itself.”
“There are complex coastlines, shallow areas, and there are dynamic, morphological changes in these areas like barrier islands, lagoons, lakes, estuaries and so on and so forth,” Dr. Cambazoglu said. These coastal and near-coastal areas are diverse and difficult to model, but the difficulty of his chosen career does not dissuade Saran. Rather, the graduate student has a distinct appreciation for the dynamic nature of his research.
“From the beginning of my career, I was thrilled about water-system engineering because it is really dynamic in terms of the changing conditions of climate and humidity,” Saran said. “It was thrilling to me, so I was tempted to go further to gain more knowledge by simulating the changing conditions of coastal zones and oceans.”
These changing conditions are something that Saran has personally seen growing up in the Gaibandha district of Bangladesh.
“Bangladesh is definitely one of the most affected countries in the world by sea-level rise,” Saran said. “Day by day, the coast is deteriorating. The frequency of extreme events like tropical storms is increasing there, and because of the sea-level rise, the frequency of coastal flooding is increasing as well. Our land is very fertile, so many people are dependent on farming, so the saline order has some very adverse effects on both our environment and economic system.”
Saran cited climate change’s drastic effects on Bangladesh as a factor that has strengthened his passion for his current research, which models the changing temperature and salinity levels within the Mississippi Sound and how this could potentially affect Mississippi Gulf Oyster populations. Both are important contributors to both the economy and environment of Mississippi’s Gulf Coast. His findings will help ecological modelers simulate what is called the Habitat Sustainability Index Model, an integral step in future oyster reef restoration efforts in the Mississippi Sound.
Saran’s research depicts what the future may look like if Mississippi and other coastal states do not take more initiatives to curb falling salinity levels. Saran’s numerical model analyzes climate data from 2019 and notes how frequently the climate of the Sound reached temperature and salinity levels that critically affect oyster populations. 2019 was the second wettest year on record for the U.S., causing the rivers that lead into the Sound to offload a significant amount of freshwater into its waters. The high level of precipitation made 2019 the first time that the Bonnet Carre Spillway has had to be operated twice within a calendar year, only furthering this already high freshwater inflow.
While this year may be a worst-case scenario for the Mississippi Sound, such conditions are becoming all the more common as global warming has led to a much higher frequency of extreme weather events in recent years, making Saran’s modeling an important step in the extensive process of repairing the Gulf Coast’s Native Oyster Reefs in response to Earth’s rapidly changing climate. To Saran, being prepared for damaging extreme weather events and acting preemptively is the only way to repair the fragile conditions of affected ecosystems like the Mississippi Sound.
“(Climate change) is not a near nightmare anymore,” Saran said. “We have to live with these changing conditions, and we have to think about how we can push back against these changes now that they are visible.”
‘That’s Actionable Science’
Saran’s model is important for the process of revitalizing and protecting the oyster populations of the Mississippi Sound, but a model alone cannot achieve this goal. Saran’s role in this process is a preemptive step, one that will inform the decisions of the engineers and community leaders who are tasked with more directly addressing this ongoing issue.
“My part is done, but the research is not done,” Saran said. “Now, they are collecting data; they are applying this data extensively; (and) then they are going to use it to provide the guidance to the stakeholders to the other policymakers so that we can really make our resiliency plan for the future.”
The revitalization effort in the Gulf is not just about oysters either. Other researchers involved in this project are working to protect the Gulf Sturgeon, another fish native to the area listed as threatened under the 1991 Endangered Species Act. The sturgeon—unlike the oyster—is mobile and difficult to monitor, so research on how the Sound’s changing conditions affect the more easily studied oyster will ultimately inform how these changes affect the sturgeon as well.
No matter the organism being studied, all of this research shares the common mission of understanding and repairing this complex ecosystem. “Overall, the larger scope of this project is to have a better understanding on how the extreme conditions in the estuarine system can be improved,” Dr. Cambazoglu said. “Once you get that understanding, that helps restoration because that’s actionable science.”
Saran’s research, as well as that of the other researchers in this project, is an important step for understanding the complex and understudied coastal ecosystem that many people call home. While Saran’s research specifically focuses on the Mississippi Sound itself, Cambazoglu observed how this body of water is but a part of a greater system that includes Lake Pontchartrain, Mobile Bay and the Mississippi River Delta. Further researching each of these areas, he asserted, will help scientists better understand the mutual relationships between these several bodies of water and consequently help aid those who call them home.
“There are lots of communities in coastal Mississippi, coastal Louisiana, coastal Alabama, you know, multiple states actually thriving, from fishing, from tourism, recreation and so on,” Cambazoglu said. “So, understanding this system and hopefully keeping the system healthy and sustainable has huge implications for the population living around it.”
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