Five themes form the basis of research by resident faculty and staff:
The Mississippi River system drains 41% of the lower 48 United States and delivers massive quantities of fresh water, sediments, and associated nutrients and chemical constituents to the adjacent continental shelf and northern Gulf of Mexico. Research programs focus on aspects of the river-shelf mixing zones and human alterations of the river and its constituents that modify the coastal zone and ocean. The Mississippi River discharge, from the current birdfoot delta southeast of New Orleans and via the Atchafalaya River on the central coast, is a dominant influence on the offshore ends of Louisiana estuaries and is increasing on the upper ends with present and planned diversions of Mississippi River water, sediments, nutrients and chemical constituents into Louisiana estuaries. Specific programs address nutrient cycling, carbon transformations, continental shelf sediments as records of historical biological change, flux and cycling of trace metals, the interaction of phytoplankton and zooplankton communities in nutrient and carbon budgets, and the distribution and dynamics of extensive zones of oxygen-depleted waters.
The estuaries and coastal waters of Louisiana team with living resources that contribute significantly to wildlife populations, commercial and recreational fisheries, and a Louisiana way of life. The success of these resources depends on an infrastructure of healthy, functioning ecosystems, such as salt marshes, mangrove stands, open bay bottoms, barrier island shores, and the coastal ocean. Several studies focus on food webs, trophic structure, and interacting biological, chemical and physical processes that support Louisiana’s high biological productivity. Several programs examine the relative abundance of groups of phytoplankton, including noxious and potentially harmful forms, in relation to nutrients that support their growth, and grazers, such as bacterioplankton, zooplankton and benthic filter feeders that control phytoplankton growth. Others focus on the transfer and fate of carbon in coastal and estuarine food webs.
Commercial and recreational fisheries are a key component of Louisiana’s environmental and economic resources. Management of these fisheries and the food webs that support them is essential in the presence of environmental deterioration, including coastal land loss and the detrimental effects of nutrient enrichment, such as noxious algal blooms and bottom-water oxygen deficiency. Research focuses on the early stages of fish larvae, including foraging capabilities, biochemical and morphometric responses to changes in feeding conditions, and the use of otoliths to record the environmental and chemical conditions of growth. The ability to rear larval fishes for potential aquaculture targets red drum, pompano, mangrove and red snapper, and cobia. Related studies include the dynamics of benthic organisms as prey in oxygen-depleted waters, mechanisms affecting the growth and health of coral reefs, and the characterization of similar ‘hard substrate’ fouling communities on offshore oil and gas platforms within Louisiana’s waters, and the cycling of mercury in water, sediments, and fish and effects on human consumers of seafood.
Human and Industrial Impacts
Some of the most intense oil and gas extraction activities in the world occur within Louisiana’s wetland, coastal and offshore environments. Studies have focused on the fate and effects of produced water discharges (oilfield brine) in coastal Louisiana and the potential for these effluents to influence hypoxia formation. Research on the communities associated with offshore oil platforms and the fishes attracted to the structures focus on the importance of these habitats in offshore waters. Land use activities within the Louisiana coastal zone (agriculture, urban development, air pollution) and externally (the Mississippi River watershed) contribute to increased levels of nutrient loading in coastal ecosystems. Several research programs focus on the effects of altered nutrient concentrations in the Mississippi River discharge on coastal productivity, phytoplankton community composition, harmful algal blooms and indicators of oxygen stress.
Coastal Change and Related Processes
Wetland loss and barrier island erosion continue to be major problems in the Louisiana coastal zone. The importance of these natural lines of protection against flooding and storm were blatantly demonstrated in the 2005 hurricane season with Katrina and Rita. LUMCON researchers study animal-sediment and predator-prey interactions on barrier islands and in salt marshes. LUMCON facilitates studies of sediment processes, plant communities, and change in habitat and living resources through its support and collaboration with the research and educational programs of the Barataria-Terrebonne National Estuary Program, as the fiscal agent for the Coastal Wetlands Planning, Protection and Restoration Act, via Louisiana State University, and as fiscal agent and member of the Board of Directors for CREST, the Coastal Restoration and Enhancement through Science and Technology program, also at LSU. LUMCON also serves as the logistical center for several marsh experiments in areas near the Marine Center.