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Environmental Dna (Edna) Surveys For The Smalltooth Sawfish, Pristis Pectinata, In The Chandeleur Islands, Louisiana, Emma M. Humphreys Aug 2021

Environmental Dna (Edna) Surveys For The Smalltooth Sawfish, Pristis Pectinata, In The Chandeleur Islands, Louisiana, Emma M. Humphreys

Honors Theses

The Critically Endangered smalltooth sawfish, Pristis pectinata, was historically found throughout tropical and subtropical coastal waters of the Atlantic Ocean. As a result of mortalities in fisheries and habitat degradation, they became largely restricted to southwest Florida in the U.S. and the Bahamas by the 1980s. However, recent public encounter reports of sawfish in the Florida panhandle, Mississippi, and Louisiana suggest this species is occasionally present in northern Gulf of Mexico waters. Targeted species surveys are needed to improve our understanding of the occurrence and status of this species in these waters. This research used environmental DNA (eDNA) methods …


Polycyclic Aromatic Hydrocarbons And The Microbiomes Of Two Benthic Species, Samantha Ells Aug 2021

Polycyclic Aromatic Hydrocarbons And The Microbiomes Of Two Benthic Species, Samantha Ells

Master's Theses

The presence of oil has been shown to affect the microbiomes of the water column, sediments, and organisms, both by altering the diversity and the composition of those microbial communities. If the microbiome is altered it may no longer provide benefits to its host organism, impacting its ability to survive. Thus, it is important to understand the effects of large-scale contamination events including the Deepwater Horizon oil spill. This study set out to examine the effects of oil exposure on the microbiome of two benthic species, southern flounder (Paralichthys lethostigma) and eastern oysters (Crassostrea virginica) to further understand the effects …


Population Parameter Estimation And Stable Isotope Analysis Of Gulf Sturgeon (Acipenser Oxyrinchus Desotoi) In The Pascagoula River, Alfonso Cohuo Aug 2021

Population Parameter Estimation And Stable Isotope Analysis Of Gulf Sturgeon (Acipenser Oxyrinchus Desotoi) In The Pascagoula River, Alfonso Cohuo

Master's Theses

Gulf Sturgeon (GS), Acipenser oxyrinchus desotoi, are a threatened, anadromous fish species in the northern Gulf of Mexico. Their range is from the Pearl River, LA, in the west to the Suwannee River, FL, in the east with a longitudinal divide at Mobile Bay, AL, creating a western population unit (WPU) and an eastern population unit (EPU). Sturgeon belonging to the WPU exhibit lower abundances, higher mortality rates, and are overall less studied than their EPU counterparts. Notable data gaps for the WPU includes the absence of recent population parameter estimations and confirmed feeding habitat. My thesis aims to …


Spatial And Seasonal Patterns Of Above- And Belowground Vegetation Biomass And Potential Drivers In The Pascagoula River Delta, Ms, Evan Grimes Aug 2021

Spatial And Seasonal Patterns Of Above- And Belowground Vegetation Biomass And Potential Drivers In The Pascagoula River Delta, Ms, Evan Grimes

Master's Theses

Coastal wetlands provide a valuable wealth of services to the greater coastal ecosystem and human communities. However, threats such as sea level rise and conservation projects, such as freshwater diversions, have the potential to alter coastal wetlands in different ways. In this thesis, I describe the effects of inundation and nitrogen on vegetation productivity using a field-sampling approach and an in situ controlled mesocosm experiment, called a marsh organ. The West Channel of the Pascagoula River contained significantly higher belowground biomass than the East Channel, which is more anthropogenically modified. Vertical distribution of belowground biomass did not strongly vary between …


Patterns Of Habitat Use And Trophic Structure In Turtle Grass (Thalassia Testudinum)-Dominated Systems Across The Northern Gulf Of Mexico, Christian Hayes Aug 2021

Patterns Of Habitat Use And Trophic Structure In Turtle Grass (Thalassia Testudinum)-Dominated Systems Across The Northern Gulf Of Mexico, Christian Hayes

Dissertations

Seagrass structural complexity is a primary driver of nekton recruitment and faunal community structure. Few studies, however, have quantified the role of seagrass complexity on habitat use and trophic structures over large spatial scales. A large-scale simultaneous survey was conducted to assess relationships of multiple seagrass morphological complexity metrics to nekton habitat use, trophic dynamics, and blue crab (Callinectes sapidus) growth and mortality across the Northern Gulf of Mexico. Seagrass morphological and nekton community characteristics depended on site and season, and regional variation in seagrass morphology was an important driver of juvenile nekton abundance, species richness, beta diversity, …


Trophic Ecology Of Mesopelagic Fish Larvae And Juveniles In The Northern Gulf Of Mexico, Emily Gipson May 2021

Trophic Ecology Of Mesopelagic Fish Larvae And Juveniles In The Northern Gulf Of Mexico, Emily Gipson

Master's Theses

The deep-pelagic environment encompasses ocean waters below 200 m depth, and comprises 90% of the volume of the Gulf of Mexico. Deep-pelagic fishes are important prey for many oceanic consumers, but relatively little is known about their early life history, including larval fish trophic ecology. An understanding of the role deep-pelagic fish larvae have in oceanic food webs is important in the development of ecosystem models that examine the connectivity (via vertical migrations) between the deep-pelagic and epipelagic environments with respect to trophic interactions, nutrient cycling, and carbon sequestration. In this study, archived plankton samples collected during 2010 and 2011 …


Assessing The Occurrence Of Trichechus Manatus Latirostris In Mobile Bay, Alabama Using Edna, Elora Pierce May 2021

Assessing The Occurrence Of Trichechus Manatus Latirostris In Mobile Bay, Alabama Using Edna, Elora Pierce

Honors Theses

In the past several decades Florida manatees (Trichechus manatus latirostris) have begun to expand their summer range into the northern Gulf of Mexico. Because this is a recent occurrence, not much is known about their habitat use and distribution in this region. Citizen-sourced sighting data suggests that Florida manatees frequent subembayments of Mobile Bay, Alabama, reaching a sighting peak in August. To assess the occurrence of manatees in this area environmental DNA surveys were used from winter (February 19-20) and summer (August 21-22) of 2018. At each of the 21 sites ranging from the mouth of Mobile Bay, …