Life Sciences Commons^™

Trophic Structure And Sources Of Variation Influencing The Stable Isotope Signatures Of Meso- And Bathypelagic Micronekton Fishes, Travis M. Richards, Tracey Sutton, R. J.David Wells

Marine & Environmental Sciences Faculty Articles

To better understand spatiotemporal variation in the trophic structure of deep-pelagic species, we examined the isotope values of particulate organic matter (POM) (isotopic baseline) and seven deep-pelagic fishes with similar diet compositions but contrasting vertical distributions across mesoscale features in the Gulf of Mexico using stable isotope and amino acid compound-specific isotope analyses. Species examined included four migratory (Benthosema suborbitale, Lepidophanes guentheri, Melamphaes simus, Sigmops elongatus) and three non-migratory zooplanktivorous fishes (Argyropelecus hemigymnus, Cyclothone obscura, Sternoptyx pseudobscura). Isotopic values of POM increased with depth, with meso- and bathypelagic samples characterized by higher δ C and δ N values relative to …

First Insights Into The Vertical Habitat Use Of The Whitespotted Eagle Ray Aetobatus Narinari Revealed By Pop‐Up Satellite Archival Tags, L. R. Brewster, B. V. Cahill, M. N. Burton, C. Dougan, J. S. Herr, L. Issac Norton, S. A. Mcguire, M. Pico, E. Urban-Gedamke, K. Bassos-Hull, J. P. Tyminski, R. E. Hueter, Bradley M. Wetherbee, Mahmood S. Shivji, N. Burnie, M. J. Ajemian

Marine & Environmental Sciences Faculty Articles

The whitespotted eagle ray Aetobatus narinari is a tropical to warm‐temperate benthopelagic batoid that ranges widely throughout the western Atlantic Ocean. Despite conservation concerns for the species, its vertical habitat use and diving behaviour remain unknown. Patterns and drivers in depth distribution of A. narinari were investigated at two separate locations—western North Atlantic (Islands of Bermuda) and Eastern Gulf of Mexico (Sarasota, Florida, USA). Between 2010 and 2014, seven pop‐up satellite archival tags (PSATs) were attached to A. narinari using three methods: a through‐tail suture; external tail‐band; and through‐wing attachment. Retention time ranged from 0–180 days, with tags attached via …

Taxonomic Richness And Diversity Of Larval Fish Assemblages In The Oceanic Gulf Of Mexico: Links To Oceanographic Conditions, Corinne R. Meinert, Kimberly Clausen-Sparks, Maëlle Cornic, Tracey Sutton, Jay R. Rooker

Marine & Environmental Sciences Faculty Articles

Biodiversity enhances the productivity and stability of marine ecosystems and provides important ecosystem services. The aim of this study was to characterize larval fish assemblages in pelagic waters of the northern Gulf of Mexico (NGoM) and identify oceanographic conditions associated with areas of increased taxonomic richness (T ) and Shannon diversity (H’). Summer ichthyoplankton surveys were conducted in the NGoM in 2015 and 2016 using neuston net (surface layer; upper 1 m) and oblique bongo net (mixed layer; 0–100 m) tows. Over 17,000 fish larvae were collected over the two-year study, and 99 families of fish larvae were present. Catch …

Combined Edna And Acoustic Analysis Reflects Diel Vertical Migration Of Mixed Consortia In The Gulf Of Mexico, Cole G. Easson, Kevin M. Boswell, Nicholas Tucker, Joseph D. Warren, Jose V. Lopez

Biology Faculty Articles

Oceanic diel vertical migration (DVM) constitutes the daily movement of various mesopelagic organisms migrating vertically from depth to feed in shallower waters and return to deeper water during the day. Accurate classification of taxa that participate in DVM remains non-trivial, and there can be discrepancies between methods. DEEPEND consortium (www.deependconsortium.org) scientists have been characterizing the diversity and trophic structure of pelagic communities in the northern Gulf of Mexico (nGoM). Profiling has included scientific echosounders to provide accurate and quantitative estimates of organismal density and timing as well as quantitative net sampling of micronekton. The use of environmental DNA (eDNA) can …

The Expanded Footprint Of The Deepwater Horizon Oil Spill In The Gulf Of Mexico Deep-Sea Benthos, Michael G. Reuscher, Jeffrey G. Baguley, Paul A. Montagna

C-IMAGE Publications

The 2010 Deepwater Horizon blowout off the coast of Louisiana caused the largest marine oil spill on record. Samples were collected 2–3 months after the Macondo well was capped to assess damage to macrofauna and meiofauna communities. An earlier analysis of 58 stations demonstrated severe and moderate damage to an area of 148 km². An additional 58 archived stations have been analyzed to enhance the resolution of that assessment and determine if impacts occurred further afield. Impacts included high levels of total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAH) in the sediment, low diversity, low evenness, and …

Hiding In Plain Sight: Elopomorph Larvae Are Important Contributors To Fish Biodiversity In A Low-Latitude Oceanic Ecosystem, Jon A. Moore, Dante Fenolio, April Coan, Tracey Sutton

Marine & Environmental Sciences Faculty Articles

Leptocephalus larvae of elopomorph fishes are a cryptic component of fish diversity in nearshore and oceanic habitats. However, identifying those leptocephali can be important in illuminating species richness in a region. Since the Deepwater Horizon oil spill in 2010, sampling of offshore fishes in the epi-, meso-, and upper bathypelagic depth strata of the northern Gulf of Mexico resulted in 8989 identifiable specimens of leptocephalus larvae or transforming juveniles, in 118 taxa representing 83 recognized and established species and an additional 35 distinctive leptocephalus morphotypes not yet linked to a known described species. Leptocephali account for ∼13% of the total …

Pelagic Habitat Partitioning Of Late-Larval And Juvenile Tunas In The Oceanic Gulf Of Mexico, Nina Pruzinsky, Rosanna Milligan, Tracey Sutton

Marine & Environmental Sciences Faculty Articles

Tunas are ecologically important in pelagic ecosystems, but due to their high economic value, large-bodied species are overfished. Declines in fishery landings of large-bodied tuna species in the Gulf of Mexico (GoM) are expected to increase fishing pressures on unmanaged, small-bodied tuna species, whose life history traits are less known. While predicting spawning stocks and recruitment success typically focuses on estimates of larval abundances, juveniles may provide a better estimate of future adult stock sizes, as they are more likely to survive to adulthood because mortality rates scale inversely with body size. However, distributional studies on juveniles are rare, leading …

The Southern Gulf Of Mexico: A Baseline Radiocarbon Isoscape Of Surface Sediments And Isotopic Excursions At Depth, Samantha H Bosman, Patrick Schwing, Rebekka A. Larson, Natalie E. Wildermann, Gregg R. Brooks, Isabel Romero, Joan-Albert Sanchez-Cabeza, Ana Carolina Ruiz-Fernández, Maria Luisa Machain-Castillo, Adolfo Gracia, Elva Escobar-Briones, Steven Murawski, David Hollander, Jeffrey P. Chanton

C-IMAGE Publications

The southern Gulf of Mexico (sGoM) is home to an extensive oil recovery and development infrastructure. In addition, the basin harbors sites of submarine hydrocarbon seepage and receives terrestrial inputs from bordering rivers. We used stable carbon, nitrogen, and radiocarbon analyses of bulk sediment organic matter to define the current baseline isoscapes of surface sediments in the sGoM and determined which factors might influence them. These baseline surface isoscapes will be useful for accessing future environmental impacts. We also examined the region for influence of hydrocarbon deposition in the sedimentary record that might be associated with hydrocarbon recovery, spillage and …

Feeding Ecology Of Red Snapper (Lutjanus Campechanus) And Vermilion Snapper (Rhomboplites Aurorubens) Coexisting At The Louisiana Shelf-Edge Banks, Katherine M. Ellis

LSU Master's Theses

Niche partitioning, the process by which competing species use different subsets of the available resources, is commonly used to explain the coexistence of closely related species. In the northwest Gulf of Mexico on the shelf-edge banks, red snapper (Lutjanus campechanus) and vermilion snapper (Rhomboplites aurorubens) are two coexisting closely related species. Yet, little is known about how these species partition resources. In this study, niche partitioning of red snapper and vermilion snapper was investigated using gut contents and stable isotopes. While dietary niche partitioning was apparent, the species relied upon similar prey and displayed isotopic niche overlap, …

Complete Mitochondrial Genome Of Carijoa Riisei (Duchassaing & Michelotti, 1860) (Octocorallia: Alcyonacea: Stolonifera: Clavulariidae), Erin E. Easton, David Hicks

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

We report the first complete Stolonifera mitochondrial genome. Carijoa riisei (Duchassaing & Michelotti, 1860) isolate CLP2_A03 was collected by scuba at 32 m on the USTS Texas Clipper (27° 53.7827′N, 93° 36.2702′W). The complete mitogenome has the ancestral octocoral gene order for its 14 protein-coding genes, two rRNA genes, and one tRNA gene. It is 18,714 bp (30.7% A, 15.8% C, 18.8% G, and 34.7% T). Of the Alcyonacea mitogenomes published to date, it is most genetically similar (94% uncorrected) to Sinularia ceramensis Verseveldt, 1977 (NC_044122).

Dynamics Of The Loop Current System And Its Effects On Surface And Subsurface Properties In The Gulf Of Mexico, Richard James Brokaw

Theses and Dissertations

Surface circulation in the Gulf of Mexico is dominated by the Loop Current System (LCS), including the Loop Current (LC) and its associated eddies. The Gulf of Mexico (GoM) also displays long-term surface gradients of temperature and salinity due to climatological features including the intrusion of warm, saline waters from the Caribbean Sea and the seasonal deposition of freshwater from the Mississippi River System caused by seasonal increases in snow melt and precipitation over the watershed. This research aims to increase the understanding of the LCS through the investigation of its relationship with these surface gradients. A classification system of …

The Vertical And Horizontal Distribution Of Deep-Sea Crustaceans In The Order Euphausiacea In The Vicinity Of The Deepwater Horizon Oil Spill, Tamara Frank, Charles Douglas Fine, Eric A. Burdett, April Cook, Tracey Sutton

Marine & Environmental Sciences Faculty Articles

The vertical and horizontal distributions of Euphausiacea in the northern Gulf of Mexico (GOM), including the location of the Deepwater Horizon oil spill, were analyzed from 340 trawl samples collected between April and June 2011. This study is the first comprehensive survey of euphausiid distributions from depths deeper than 1000 m in the GOM and includes stratified sampling from five discrete depth ranges (0–200 m, 200–600 m, 600–1000 m, 1000–1200 m, and 1200–1500 m), and expands the depth ranges of 30 species. In addition, this study demonstrates significantly higher abundance and biomass of the euphausiid assemblage from slope vs. offshore …

Oceanographic Structure And Light Levels Drive Patterns Of Sound Scattering Layers In A Low-Latitude Oceanic System, Kevin M. Boswell, Marta D'Elia, Matthew Johnston, John A. Mohan, Joseph D. Warren, R. J. David Wells, Tracey Sutton

Biology Faculty Articles

Several factors have been reported to structure the spatial and temporal patterns of sound scattering layers, including temperature, oxygen, salinity, light, and physical oceanographic conditions. In this study, we examined the spatiotemporal variability of acoustically detected sound scattering layers in the northern Gulf of Mexico to investigate the drivers of this variability, including mesoscale oceanographic features [e.g., Loop Current-origin water (LCOW), frontal boundaries, and Gulf Common Water]. Results indicate correlations in the vertical position and acoustic backscatter intensity of sound scattering layers with oceanographic conditions and light intensity. LCOW regions displayed consistent decreases, by a factor of two and four, …

Chronic Pah Exposures And Associated Declines In Fish Health Indices Observed For Ten Grouper Species In The Gulf Of Mexico, Erin Pulster, Adolfo Gracia, Maickel Armenteros, Brigid Carr, Justin Mrowicki, Steven Murawski

C-IMAGE Publications

Ten grouper species grouper (n = 584) were collected throughout the Gulf of Mexico (GoM) from 2011 through 2017 to provide information on hepatobiliary polycyclic aromatic hydrocarbon (PAH) concentrations in the aftermath of the Deepwater Horizon (DWH) oil spill. Liver and bile samples were analyzed for PAHs and their metabolites using triple quadrupole mass spectrometry (GC/MS/MS) and high-performance liquid chromatography with fluorescence detection (HPLC-F), respectively. Data were compared among species and sub-regions of the GoM to understand spatiotemporal exposure dynamics in these economically and ecologically important species. Significant differences in the composition and concentrations of PAHs were detected spatially, …

Comparative Population Genomics And Biophysical Modeling Of Shrimp Migration In The Gulf Of Mexico Reveals Current-Mediated Connectivity, Laura Timm, Lys M. Isma, Matthew Johnston, Heather D. Bracken-Grissom

Biology Faculty Articles

The Gulf of Mexico experiences frequent perturbations, both natural and anthropogenic. To better understand the impacts of these events, we must inventory natural variability within the ecosystem, communities, species, and populations, and contextualize these findings in relation to physical features. Here, we present an integrated study of comparative population genomics and biophysical oceanography. Targeting three species of mesopelagic shrimp common to the Gulf of Mexico midwater (Acanthephyra purpurea, Systellaspis debilis, and Robustosergia robusta), we analyzed genetic diversity and population connectivity as proxies for species health and resilience, respectively. We also simulated a range of vertical migratory behaviors …

Comparative Population Genomics And Biophysical Modeling Of Shrimp Migration In The Gulf Of Mexico Reveals Current-Mediated Connectivity, Laura Timm, Lys M. Isma, Matthew Johnston, Heather D. Bracken-Grissom

Biology Faculty Articles

The Gulf of Mexico experiences frequent perturbations, both natural and anthropogenic. To better understand the impacts of these events, we must inventory natural variability within the ecosystem, communities, species, and populations, and contextualize these findings in relation to physical features. Here, we present an integrated study of comparative population genomics and biophysical oceanography. Targeting three species of mesopelagic shrimp common to the Gulf of Mexico midwater (Acanthephyra purpurea, Systellaspis debilis, and Robustosergia robusta), we analyzed genetic diversity and population connectivity as proxies for species health and resilience, respectively. We also simulated a range of vertical migratory behaviors …

Impacts Of The Deepwater Horizon Oil Spill On Reproduction And Ontogeny Of Gulf Killifish (Fundulus Grandis), Charles Alexander Brown

LSU Doctoral Dissertations

On April 20, 2010, the Deepwater Horizon oil spill released an estimated 779 million liters of Macondo-252 crude oil into the Gulf of Mexico, making it the largest marine oil spill in history. Over a thousand kilometers of marshland that many species of fish use as a spawning grounds and nurseries was oiled, exposing breeding adult fish and their offspring to oil. My dissertation investigates the impacts of the Deepwater Horizon oil spill and associated remediation efforts on the reproduction and ontogeny of a sentinel ecotoxicological species, the Gulf killifish (Fundulus grandis). Concerns were raised regarding use of …

Gulf Coast Marine Laboratories Past, Present And Future, Donald F. Boesch

Gulf and Caribbean Research

I spent my nearly 50—year career in marine science working at marine laboratories, most of that as a chief executive officer. So, it is appropriate that my reflections are about marine laboratories, rather than my own science. After relating my career course, I turn my attention to the history and development of marine laboratories along the U.S. coast of the Gulf of Mexico (GOM). Surprisingly, the region’s first laboratory was actually constructed in 1903 at Cameron, LA, but operated less than a decade before closing. It was not until after World War II that the university—affiliated marine laboratories of today …

Coral Reefs In The Gulf Of Mexico Large Marine Ecosystem: Conservation Status, Challenges, And Opportunities, Diego L. Gil-Agudelo, Carlos E. Cintra-Buenrostro, Jorge Brenner, Patricia Gonzalez-Diaz, William Kiene, Caitlin Lustic, Horacio Perez-Espana

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

The importance of coral reefs (CR) within marine ecosystems has become widely recognized. Although shallow CR are not as abundant in the Gulf of Mexico (GoM) as in other areas such as the Caribbean, their uniqueness, singularity, isolation, and conservation status make their conservation highly important. Corals and CR, both shallow and deep, are more widely distributed throughout the GoM than previously thought, providing new venues of research but also new challenges for their sustainable management. They are widely present in the three countries circumscribing the GoM (Cuba, Mexico, and the United States). Corals are also distributed throughout different depths, …

Development Of Highly Sensitive Environmental Dna Methods For The Detection Of Bull Sharks, Carcharhinus Leucas (Müller And Henle, 1839), Using Droplet DigitalTm Pcr, Katherine E. Schweiss, Ryan N. Lehman, J. Marcus Drymon, Nicole M. Phillips

Faculty Publications

Background: As apex and mesopredators, elasmobranchs play a crucial role in maintaining ecosystem function and balance in marine systems. Elasmobranch populations worldwide are in decline as a result of exploitation via direct and indirect fisheries mortalities and habitat degradation; however, a lack of information on distribution, abundance, and population biology for most species hinders their effective management. Environmental DNA analysis has emerged as a cost‐effective and non‐invasive technique to fill some of these data gaps, but often requires the development of species‐specific methodologies.

Aims: Here, we established eDNA methodology appropriate for targeted species detections of Bull Sharks, Carcharhinus …