Charlie Martin, Ph.D.
Senior Marine Scientist
Assistant Professor, Department of Marine Sciences, University of South Alabama
Charlie Martin is an Assistant Professor in the Department of Marine Sciences at the University of South Alabama and a Senior Marine Scientist at the Dauphin Island Sea Lab. He completed his undergraduate and Ph.D. at the University of South Alabama and served as a postdoctoral researcher at Louisiana State University. Prior to joining the faculty, he was a faculty member at the University of Florida Nature Coast Biological Station. Charlie’s research focuses on estuarine and coastal ecology, most notably the effects of anthropogenic stressors on ecological systems.
In my lab, we conduct broad and applied ecological research focused on the conservation of marine and estuarine ecosystems. Specifically, we seek to identify the effects of anthropogenic stressors on coastal ecosystems using field-oriented and experimental approaches. My research program focuses on question-driven research, and, as such, I seek organisms/systems providing novel ecological insight rather than focusing on organism-specific hypotheses. The ultimate objective of our research is to gain a fundamental understanding of the ecological processes structuring natural ecosystems, particularly how anthropogenic perturbations have modified these processes, with a specific emphasis on the continued conservation of Gulf of Mexico estuaries, such as the Mobile-Tensaw Delta in Alabama.
Our lab’s research foci are thus very broad, though we tend to focus on several overarching topics:
Introduced Species: Introduced species are among the greatest of all threats to the structure and function of native ecosystems. We have worked extensively with freshwater invaders that extend their distribution into estuaries, such as Eurasian milfoil, hydrilla, apple snails, and Nile tilapia. Overall, we seek to: 1) link environmental conditions to field distributions to determine factors limiting dispersal into estuaries, 2) determine the ecological effects of these novel species, and 3) provide management recommendations for mitigating, restoring, and preventing invasions. I currently serve editorial roles for several invasive species journals and continue to pursue an understanding of coastal invaders.
Salinity Alteration in Estuaries: Along the Gulf coast, freshwater is a key resource, and alterations to hydrology can drastically modify our estuaries. For example, reductions in freshwater discharge contributed to the recent collapse of oysters in Apalachicola Bay, FL. In LA, wetlands are being lost at an unprecedented rate of over 40 km 2 per year, largely due to a lack of sediment supply supplied from the freshwater inflow. One solution to arrest this wetland loss is to reestablish the natural hydrology of the delta, through freshwater diversions from the Mississippi River (MR) that will bring sediment from the river to replace lost land. We are currently investigating the reintroduction of the MR near Port Sulphur, LA to determine how freshwater introduction will affect faunal community composition and food webs in restored and unrestored marshes. Moreover, ongoing work in the Mobile-Tensaw Delta seeks to determine the effect of barriers such as the Hwy 90 causeway on local ecological structure and function.
Plant-Animal and Food Web Interactions: Key interactions among animals, their habitats, and plants can have a strong, structuring role in estuarine systems. Our lab studies the relationships between animals and their habitats (e.g., habitat associations, herbivory, refugia, etc.) as well as how individual interactions may scale up to the broader food web. In addition, recent evidence has indicated that the mere presence of predators can have strong, cascading impacts throughout the food web (i.e., ‘the ecology of fear’). We seek to determine factors influencing how prey recognize and respond to the threat of predators and the multitude of factors and stressors that can disrupt these interactions.
Restoration: Given the continued loss of habitat in many areas, environmental managers have turned to restoration practices to re-establish ecosystem functioning and supplement local fisheries. Our group has worked extensively on various restoration projects, including submerged vegetation, oyster reefs, and salt marshes. Moreover, our lab has investigated restoration in numerous ways – from determining restoration of ecosystem services (such as habitat for nekton) to best management practices and novel
techniques for restoring critical estuarine habitat.
Climate Change and Other Disturbances: Global climates are changing rapidly, with rising sea levels, increasing weather variability affecting freshwater discharge, and intensifying temperatures. Changes to these environmental conditions have consequences for estuaries. We have studied the effects of such changes, including the “tropicalization” of coastal areas, the effects of high-intensity storms such as Hurricane Michael, and (as previously noted) salinity alterations. Of specific note is our work with range-expanding, tropically-associated consumers such as Common Snook, including documenting their spread, monitoring seasonal movements and thermal refuge use in coastal springs using acoustic telemetry, and quantifying interactions with resident organisms in the Suwannee River watershed. We are also interested in the ecological effects of other unplanned anthropogenic disturbances – including oil perturbations (e.g., the Deepwater Horizon oil spill), fish kills, and hypoxic conditions.
Adams, C., L.K. Reynolds, C.W. Martin, C. Rohal, J. Slater, R. Goebel. Common wetland plants of Lake Apopka, Florida (USA). EDIS https://doi.org/10.32473/edis-EP627-2023.
McDonald, A.M., C.W. Martin, C.R. Adams, L.K. Reynolds. Competition in a changing world: environmental stressors during seasonal vulnerability limits benefit of resource pulse to invasive macrophyte. In Press. Ecosphere.
Keppeler, F., J. Junker, M. Shaw, A. Engel, A.M. McDonald, B.J. Roberts, C.W. Martin, E.M. Swenson, J.A. Olin, L.M. Bui, M.J. Polito, N.N. Rabalais, O.P. Jensen, P.C. Lopez-Duarte, R. Rossi, S.B. Alford. Can created marshes harbor similar biodiversity to natural marshes? A scale-dependent approach from microbes to top predators. In Press. Ecosphere.