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Research Projects

 

Effects of ocean acidification on fish prey at artificial reefs in the northern Gulf of Mexico: testing benthic species sensitivities and altered interactions

This is a NOAA-LA Sea Grant Ocean Acidification Graduate Research Fellowship grant. Our global research aim is to understand potential ecological consequences of increasing CO2 concentrations on artificial reef fish production in nGoM. As a first step, we will focus on effects of acidification on adult benthic invertebrate species that are fed upon by fishes. Our research objectives (obj.) are twofold. Obj. 1 is to test sensitivity of benthic invertebrate species to acidification at increasing temperatures. Obj. 2 is to test whether acidification combined with warming will alter species susceptibility to fish consumption.

Building resilience into seagrass bed restoration: The role of genetic variation

This is a NOAA Restore planning project. Seagrass beds provide important ecosystem services — they reduce erosion during storm surges, they provide habitat for commercially important fish species, and they sequester carbon. Seagrasses are threatened by natural and human factors, including changes in water quality that are driven by climate change. Managers are planning restoration projects amid growing environmental uncertainties, and one way to increase resiliency is to better understand the genetic diversity of existing beds. The project involves efforts to reduce the uncertainties of seagrass restoration by considering the impacts of genetic variation in remaining seagrass beds. The study involves conducting a literature review, compiling data on seagrass health, and hosting a Seagrass Restoration Workshop. 

Trace element pollutants in tissues of fishes at artificial reefs in the northern Gulf of Mexico: are recreational anglers at risk from seafood consumption?

This is a joint undergraduate and graduate project funded by Sea Grant UROP. Trace element pollutants (TEPs) such as As, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, V and Zn can accumulate in reef fish tissues and in turn be transferred to humans through consumption of seafood. Trace element pollutants have been shown to have negative consequences on human health. Aquatic ecosystems in the vicinity of Louisiana and along the northern Gulf of Mexico (nGoM) may be particularly vulnerable to TEPs because the Mississippi River and the other river tributaries, transport TEPs produced from industrial, municipal, and agriculture waste into coastal waters. Once TEPs enter these waterways they are not easily removed, nor degraded by natural processes, subsequently accumulating in the water, fishes, and sediment. Our research focuses on the quantification of TEP concentrations in the tissues of fourteen fish species that vary in ecology (e.g., diet and reef residency and association) from artificial reefs in the nGoM. We will analyze TEPs in tissues of various reef species collected from six artificial reefs to answer the following three questions: Q1) Do fish species targeted by recreational anglers have greater concentrations of TEPs in their muscle tissues than non-target species? Q2) Do targeted fishery species of legal harvest size have greater concentrations of TEPs in muscle tissues than those of non-legal size? And Q3) Do trace element concentrations in liver or muscles differ and does one tissue type seem to be a better indicator of bioaccumulation? This research will provide a comprehensive analysis of the risk of recreational anglers to harmful TEPs when consuming fishery species from nGoM artificial reefs.

Determining the correlation between heavy metal contamination and marine ecosystem resilience in sediment, biological samples (seafood), seawater and seagrass collected in Abaco Island, The Bahamas after a catastrophic storm event 

Fighting invasion through aquafeed: Can invasive carp be used as a food source in farmed catfish diets? Determination of Hg contamination in invasive carp using ICP-QQQ

Metal contamination effects on microbial carbon cycling in fresh and marine waters 

Soluble iron mediates the microorganism-dependent oxidation of solid GaAs: Determination of As (III) and As (V) using HPLC-IC-ICP-QQQ 

Spatiotemporal patterns of metal contaminants and carbon chemistry in rivers undergoing large restoration efforts 

Analysis of Fe in digested blood samples collected from women and children

Sponges as passive samplers for heavy metals in freshwater and brackish systems 

Chandeleur Islands Post-Berm Physical Processes and Restoration Plan

The Chandeleur Islands were once a much larger and robust barrier island chain that has experienced severe erosion and degradation by more than a decade of intense hurricanes that began with Hurricane Georges in 1998. In addition these islands were heavily oiled from the MC 252 Oil Spill in 2010. As part of the oil spill response, 6.1 miles sand berm were constructed along the north end of the islands. The objective of this study is to assess the physical impact of the berm, evaluate options to modify the berm to enhance the ecologic function and longevity of the Chandeleur Islands, and develop a coastal restoration plan for the Chandeleur Islands.

Sedimentary Framework of the Eastern Isles Dernieres

The objective of this study is to develop a conceptual sedimentary framework and budget of the eastern end of the Isles Dernieres barrier arc system, specifically including East Island and Trinity Island. The characteristics of this systems’ sediment budget, sedimentary facies, and barrier lithosome evolution are of particular interest from a commerce perspective related to the adjacent Houma Navigation Canal, a coastal barrier restoration perspective, and the fundamental geologic framework of a highly transgressive barrier arc systems.

Sustainably Yours: Quantifying Debris

This is a sub-grant from LDWF on an EPA Environmental Education Grant (Region 6). The sub-grant allows UNO-PIES CEP to work with Venise Ortego from LDWF and the Louisiana Environmental Education Commission on field experiences related to marine debris, for teachers and students from Region 6 states. We have completed two teacher professional development workshops and five student field trips. Most of the work has taken place at Rockefeller Refuge in Cameron Parish, with marine debris collection and analysis taking place on the beaches of Cameron Parish (Rutherford and Holly Beaches).

Rx for the Coast: Preparing the Next Generation to Protect New Orleans

This is a sub grant with Benjamin Franklin High School on a NOAA BWET grant. The project engages high school students in problem-based inquiry research in STEM disciplines, while focusing on the importance of the coastal wetlands that surround the city of New Orleans. Ben Franklin High School, Patrick Taylor Science and Technology Academy, and Holy Cross High School are all participants in the project.

Habitat Restoration

This is a contract with Waldemar Nelson Engineering, in which UNO-PIES CEP conducts field workshops as a part of a project with Freeport MacMoran’s habitat restoration project at the AMAX site in Braithwaite, Plaquemines Parish. This project has brought many groups of students to the site to inventory the fauna and flora. The project will move into a second phase to focus on restoration and invasive species management this fall.

Lower Mississippi River Response to Diversions Phase II

The construction of levees and upstream dams has resulted in starving the coastal wetlands of the historical supply of sediment and nutrients. In the natural process, the annual river floods would supply sediments and nutrients so that the combination of biological production and sediment deposition would compensate for subsidence. The purpose of some of the proposed diversions is to re-establish this natural function of the river with respect to the coastal wetlands. The objective of this study is to develop modeling tools that can be used to assess sediment and freshwater diversions in the Lower Mississippi River with modifications to the channels in the Bird’s Foot Delta.

2017 Master Plan Model Development and Application

The purpose of this project is to develop an integrated modeling tool that will incorporate the coastal hydrodynamics, sediment transport, water quality, morphology, fisheries and vegetation and will be designed to run 50-year time sequences that efficiently and accurately predict the effects of projects at the basin-scale, as part of the 2017 Coastal Master Plan.

Mississippi River Project Modeling Support for the LCA Mississippi River Hydrodynamic and Delta Management Study (Delft3D Model)

This project is part of a large study being conducted by the State of Louisiana (CPRA) in cooperation with the U.S. Army Corps of Engineers (ERDC). The modeling effort for this study is “Mississippi River Hydrodynamic Modeling” (MRHDM). The UNO component in the proposal involves developing a 3-D Regional model to predict the River responses to various diversion scenarios specified by CPRA.

Cooperative Research and Development of Turtle Excluder Devices (TEDs) for the Louisiana Skimmer Trawl Shrimp Fishery

The purpose of this study is to improve upon the design, testing, and implementation of Turtle Excluder Devices in the Louisiana Skimmer Trawl Shrimp Industry through collaboration between a network of fishermen, Coastal Community Consulting (CCC), 91ֱ�� (UNO), and National Marine Fisheries Service (NMFS).

Habitat Suitability Index Model Development – Wildlife, Fish, and Shellfish

The focus of this project is to make improvements to a Habitat Suitability Index model that is used to evaluate the potential effects of projects on wildlife, fish, and shellfish. This model will be used in planning projects for the 2017 Coastal Master Plan.

Abundance and distribution of commercially important estuarine dependent species populations within the Gulf of Mexico: BOEM Cooperative Agreement

The purpose of this study is to assess Gulf of Mexico (GOM) blue crab (Callinectes sapidus), white shrimp (Litopenaeus setiferus) and brown shrimp (Farfantepenaeus aztecus) population abundance and distribution using existing data sets as a baseline and supplemental data from continued sampling. Understanding the abundance and distribution of these three commercially and ecologically important species would not only aid in future impact analyses of the species, but could also demonstrate the overall ecological health within the northern GOM estuaries and possibly indicate long-term impacts to a lucrative commercial fisheries industry.

Modeling exchange processes in the Lower Mississippi River; saltwater intrusion dynamics in response to constructed sediment diversions.

Large sediment diversion structures constructed to build land in coastal Louisiana need fully assessment in terms of design and operation, and a full analysis of the impacts to receiving basin ecosystems are required. An aspect of the analysis is the lower Mississippi River and its response to changes in discharge (flow) in the river will after saltwater instruction in the lower delta, and compromise freshwater intakes in the Orleans and Plaquemines parishes. Three-dimensional hydrodynamic and salinity transport models were used and validated for present conditions without the implementation of projects, and were then used to simulate future conditions with project (diversions) implementation. Several scenarios were simulated some of which include climate change driven sea level rise.

Development and morphology of point bars in tidal rivers, observations from Sapelo and the Altamaha River, GA

Many tidal creeks and rivers exhibit bars associated with meander bends. However, hydrodynamic and morphodynamic studies of these point-bars are scarce, compared with the extensive studies of fluvial-point bars. The few studies that have been undertaken suggest significant differences between tidal bars and their fluvial counterparts, including low rates of channel migration, a unique planform morphology resulting from the bi-directional tidal flows and tidal asymmetry, and variation in stage-discharge behavior. We examine point-bars in two closely situated estuaries on the Georgia coast: the Altamaha and Sapelo. Both sites are meso-tidal; however, the Altamaha has significant fluvial input, whereas the Sapelo creeks have minimal fluvial input. Both sites exhibit mixed sand-mud point bars of various sizes. However, sites dominated by fluvial processes are coarser-grained and contain a higher percentage of sand. Velocity measurements from vessel-mounted and moored acoustic Doppler current profilers record the separation of flood and ebb flows to either side of the tidal bars, which results in a residual circulation over their surface. Large bedforms with opposing migration directions are observed on either side of the bar, suggesting that each side of the channel experiences a separate sediment transport regime. Shallow seismic data at two resolutions (Boomer and Chirp) indicate that the internal architecture of the tidal bars consists of lateral accretion surfaces with multi-directional strike orientations and dips, suggesting a more complex pattern of growth and development. We compare and contrast the hydrodynamics and the resulting morphologies of the bars and identify differences between fluvially-influenced and purely tidal environments. This data set also allows us to examine the hypothesis that these forms are scale invariant by examining a wide range of bars in both large and small channels.

Do crevasse splays obey delta laws, and implications for delta building in the modern delta.

Using a populated database of a few large deltas from Edmonds and Slingerland (2007), and adding twelve crevasses created by the U.S. Fish and Wildlife Service in the Delta National Wildlife Refuge (DNWR) in the modern Mississippi river Delta (MRD), as well as data from the well-established crevasse Brant’s splay within the Cubits Gap subdelta, we test the hypothesis that small crevasses channel network laws similar to those of large and laboratory scale deltas. Data were obtained using a combination of geospatial tools such as ArcGIS and Google Earth® followed by image analysis to obtain planform metrics (such as channel length and width), while channel depths where obtained from crevasse project data reports provided by CPRA and bathymetric datasets from Esposito et al., (2013). The data sets were supplemented additionally by Boyer et al., (1997) data, updated to reflect more recent land gain. Additional variables, such as, crevasse proximity to the thalweg of the order channel, distance from the main stem of the Mississippi River, flow percentages and sediment load (Allison et al., 2012) and local subcritical Froude numbers and shear velocity (Esposito et al. 2013; Clark et al., 2013) were also added to the datasets. While the large delta dataset was later supplemented by laboratory scale deltas as well as deltas produced using numerical models, there exist a paucity of similar analysis for deltas that are smaller than the Wax lake Delta (WLD) in Louisiana, which is a bayhead delta that is approximately 5 to 10 times larger in size than active crevasse splays within the MRD. Results show that these smaller deltas (crevasses) do in fact obey general deltas growth laws, as well as area and perimeter scaling laws and can good analogs for sediment diversions aimed at building land in the MRD.

Selected Past Research Projects

Tracking Lake Pontchartrain bull sharks (Carcharhinus leucas)

The objective of this research study was to tag bull shark pups with Vemco acoustic tags and track their movements within the Lake, in order to discover where these sharks are going to find prey. This is important because the prey items of young bull sharks are the same as for larger recreational teleost species such as speckled trout and redfish. This information can be used to improve habitat conditions and recreational fishing in other areas of Lake Pontchartrain.

Monitoring of introduced tilapia (Oreochromis sp.) populations following removal efforts in Port Sulphur, Louisiana

The purpose of this study was to monitor the population of introduced tilapia in Port Sulphur, LA. The introduction of tilapia has caused widespread ecological damage and has impacted native fishes where they have escaped from captivity. Monitoring the populations was used to determine the success of eradication efforts in 2009, to track any possible increases in population and dispersion of tilapia, and to assess the repopulation of treated water bodies by native fishes.

Assessing blue crabs (Callinectes sapidus) in the Pontchartrain Estuary after the Deepwater Horizon oil spill: a comparison of numbers between pre-oil spill baseline data and post-oil spill collections

The purpose of this study was to determine if post-oil spill numbers for adult blue crabs are significantly different than historical data. Less mobile aquatic organisms, such as invertebrates, can be more accurate indicator species of the short- and long-term effects of the oil spill. This study compared samples from post-oil spill collections to long-term baseline data for this species.

Restoration fishery management in Bayou St. John and City Park– Assessing baseline data on reintroduced red drum (Sciaenops ocellatus) and native fish assemblages to determine their responses to restoration activities

In collaboration with the LDWF, the Aquarium of the Americas, and local red drum tournaments, this study was conducted in order to assess habitat restoration efforts by tracking the movement, growth, and habitat choices of red drum in Bayou St. John.

Assessment and Evaluation of Mississippi River Diversion Flows for Land Building and Restoration

A set of regional hydrodynamic models with varying resolution ranging from 20 – 1,000 meters were developed, calibrated and validated using field observations of velocity, temperature, salinity and flow at selected waterways. The models were then used to determine if hypothetical large freshwater and fine sediment diversions from the Mississippi River would settle into receiving basin estuaries and eventually build land. A matrix of simulations with varying flows from the River was used to evaluate the receiving basin environmental conditions in response to these flow inputs, under various climatic scenarios and seasonal time-scales. Project results were submitted to the National oceanic and Atmospheric Administration, and were shared with the State of Louisiana, the US Army Corps of Engineers and other entities that are interested in design and construction of sediment diversion projects.

Storm induced inundation and coastal hazard vulnerability assessment in the northern Gulf of Mexico

This project was in collaboration with the United States Geological Survey, with central objectives in understanding coastal inundation risks and possible vulnerabilities along the Gulf Coast States, and considered the effects of future inundation factoring sea level rise, the effect of levee construction, barrier island restoration and beach nourishments projects on possible increase in storm surge, and inland flooding. Our results from the physical processes of inundation were shared with project ecologists who derived ecosystem metrics for possible impacts resulting from such projects.

Hydrodynamic and geomorphic controls on delta building

While river deltas are one of the major repositories for sediments and carbon on Earth, there exists a paucity of field data on the formation of distributary mouth bars—one of their key features. Here we present results from an experiment that tested a model of mouth bar development using hydroacoustic, optical, sedimentary, and geochemical tools on a mouth bar in a crevasse splay near the mouth of the Mississippi River. Our results validate an existing model for mouth bar development, which we extend to explain mouth bar stratigraphy. We propose that changes across a hydrological cycle are important for mouth bar development, resulting in a stratigraphy that has alternating fine and coarse grain sediments. Results also indicate that sand is carried up to 6 km from the main stem of the Mississippi River, despite repeated channel bifurcations, which has important implications for understanding of coastal sedimentary systems, and the restoration of large deltas. The field data (hydrodynamics, bathymetry, sediment concentrations and velocities) were used to setup and validate a hydrodynamic and sediment transport model within the Cubits Gap subdelta, using DELFT3D. Seasonal sedimentation was reproduced by the model and the model was then used to forecast future evolution of this sub-delta under varying upstream and downstream boundary conditions.