Current Search: UWF Theses (x) » Pomory, Christopher M. (x)
VIEW ALL ITEMS
- Title
- MICROBIAL BIOGEOGRAPHY IN THE WATER COLUMN AND SEDIMENTS OF THE NORTHEASTERN GULF OF MEXICO.
- Author
- Henriksson, Nine Lisa, Snyder, Richard A., Moss, Joseph A., Pomory, Christopher M., Jeffrey, Wade H., University of West Florida
- Abstract/Description
-
Through their metabolic activities marine microbes are essential for marine biogeochemical cycles. Charting their spatial distribution and biogeographical patterns is important in order to increase knowledge of what drives these microbial communities. We evaluated the bacterial communities at 22 locations in the northeast Gulf of Mexico during the summer months of 2013. Surface, water column, and surface sediment samples totaled 91 communities. Metadata and physical parameters measurements...
Show moreThrough their metabolic activities marine microbes are essential for marine biogeochemical cycles. Charting their spatial distribution and biogeographical patterns is important in order to increase knowledge of what drives these microbial communities. We evaluated the bacterial communities at 22 locations in the northeast Gulf of Mexico during the summer months of 2013. Surface, water column, and surface sediment samples totaled 91 communities. Metadata and physical parameters measurements were collected at each location. Seawater (~20L) was collected on Sterivex filters and stored at -80U+00B0 C until gDNA extraction and subsequent Illumina sequencing (MiSeq), targeting the 16S rRNA gene. OTU picking routines generated over 280,000 OTU's and identified >14 million sequences across the dataset. Alpha diversity estimates revealed significant distinction between water column samples (Surface and Intermediate samples) and benthic samples (Sediment, Core and WOC) in terms of richness and Chao1 diversity, with the latter group prevailing. The eight most prevalent OTU's comprised 15% of the dataset population and were predominantly located in water column samples; Synechococcus (5.29%), Alteromonas (1.6%) and Prochlorococcus (1.51%) were the only groups previously classified. In contrast, most of these highly abundant groups existed in very small numbers in the benthic samples. Significant correlation was found between environmental parameters and the water column biological community. According to primer6 BEST analysis, temperature, longitude, dissolved oxygen, fluorescence, and nitrate/nitrite exert notable influence on the northeast GoM bacterial community structure.
Show less - Date Issued
- 2017
- Identifier
- WFE0000572, uwf:61178
- Format
- Document (PDF)
- Title
- MOVEMENT AND BEHAVIOR OF THE SAND DOLLAR, MELLITA TENUIS.
- Author
- Earls, Ashley Brianna, Pomory, Christopher M., Darby, Philip C., Janosik, Alexis M., University of West Florida
- Abstract/Description
-
Mellita tenuis occurs in large aggregations numbering in the tens per m2. Due to their high density they are considered major bioturbators of their environment. This investigation of ecological factors affecting their movement and behavior has provided a deeper understanding of the basic biology and ecological connectivity of this species. In this study, M. tenuis was placed in an enclosure under varying treatments and video recorded. The recordings were analyzed for activity, movement,...
Show moreMellita tenuis occurs in large aggregations numbering in the tens per m2. Due to their high density they are considered major bioturbators of their environment. This investigation of ecological factors affecting their movement and behavior has provided a deeper understanding of the basic biology and ecological connectivity of this species. In this study, M. tenuis was placed in an enclosure under varying treatments and video recorded. The recordings were analyzed for activity, movement, covering, distance travelled, and velocity. Contrary to existing literature, which has been primarily based on qualitative observations, there was no significant diel rhythm found for any of the variables studied among time of day treatments. Neither feeding history nor predator presence had significant effects, however, size was found to affect covering and velocity, with large individuals moving at a rate nearly two times faster and covered significantly less often than small individuals. Density differences resulted in a change in rotational activity, with individuals in low densities more active than those in high densities. The size of other individuals in the immediate area did not have a significant effect on any of the variables, although a higher sample size is recommended for borderline results.
Show less - Date Issued
- 2016
- Identifier
- WFE0000530, uwf:61247
- Format
- Document (PDF)
- Title
- SPECIATION IN TWO CLOSELY RELATED SPECIES OF THE STARFISH LUIDIA.
- Author
- Molina, Maria del Pilar Cortes, Pomory, Christopher M., Chung, Hui-Min M., Bennett, Wayne A., University of West Florida
- Abstract/Description
-
Recently established species Luidia lawrencei was compared to Luidia clathrata in order to determine whether their recent separation is supported by behavioral and physiological responses, as well as genetic differences. Behavior was assessed by recording choice of substrate for burial among four grain sizes (125, 250, 500 and 1000 ìm). Physiological responses were assessed by recording changes in activity level as a response to acute reduction in salinity. Genetic homology was assessed using...
Show moreRecently established species Luidia lawrencei was compared to Luidia clathrata in order to determine whether their recent separation is supported by behavioral and physiological responses, as well as genetic differences. Behavior was assessed by recording choice of substrate for burial among four grain sizes (125, 250, 500 and 1000 ìm). Physiological responses were assessed by recording changes in activity level as a response to acute reduction in salinity. Genetic homology was assessed using segments within the cytochrome oxidase I (COX-I) mitochondrial gene. Substrate preference trials suggested that Luidia clathrata has a preference towards smaller grain sizes, while no definite preference was found for Luidia lawrencei and no significant difference was found between the species. Salinity trial results indicated that Luidia lawrencei is more active at salinities 25 psu and higher, while Luidia clathrata is more active at salinities lower than 25 psu. Mitochondrial genome comparison returned over 99% homology among these species. While the sediment and salinity data indicate a difference in responses to habitat differences, the COX-I genetic result is strong evidence that does not support the recently proposed separation of these species contrary to what has been previously published.
Show less - Date Issued
- 2011
- Identifier
- WFE0000287, uwf:60897
- Format
- Document (PDF)
- Title
- TAKE MY BREATH AWAY... PHYSIOLOGICAL RESPONSES OF ATLANTIC STINGRAYS, DASYATIS SABINA, TO CYCLING HYPOXIA.
- Author
- Dabruzzi, Theresa Francine, Bennett, Wayne A., Behan, Kristina J., Pomory, Christopher M., University of West Florida
- Abstract/Description
-
Atlantic stingrays, Dasyatis sabina, inhabit shallow water seagrass habitats where they experience temperature and salinity fluctuations, as well as natural cycles of hypoxia. In this study I examined changes in gill morphology, critical oxygen minimum, and hemoglobin/hematocrit levels in Atlantic stingrays acclimated for 20 days at normoxia (.5.50 mg/l), or normoxia with 6 hour intervals of moderate (4.0 mg/l), or marked hypoxia (2.0 mg/l). Neither hematocrit (Range 7.3-7.6 g/dl) nor...
Show moreAtlantic stingrays, Dasyatis sabina, inhabit shallow water seagrass habitats where they experience temperature and salinity fluctuations, as well as natural cycles of hypoxia. In this study I examined changes in gill morphology, critical oxygen minimum, and hemoglobin/hematocrit levels in Atlantic stingrays acclimated for 20 days at normoxia (.5.50 mg/l), or normoxia with 6 hour intervals of moderate (4.0 mg/l), or marked hypoxia (2.0 mg/l). Neither hematocrit (Range 7.3-7.6 g/dl) nor hemoglobin (Range 24.3-26.7%) mean values differed significantly across treatments. Perhaps the existing hemoglobin is sufficient, or stingrays have switched to a more efficient isoform. Gill dimensions including number of primary filaments, primary filament length, and number of secondary lamellae show increasing trends with severity of hypoxic exposure. Mass specific gill surface areas ranged between 85 and 140 mm2/g, and showed a significant 1.7 fold increase in total surface area between the normoxic and markedly hypoxic treatment group. Fish in the normoxic group had significantly higher critical oxygen minima (0.67±0.11 mg/l) than stingrays in either hypoxic treatment (0.40±0.05, and 0.42±0.06 mg/l). Gill remodeling improves hypoxia tolerance and likely allows Atlantic stingrays to successfully exploit hypoxic habitats inaccessible to predators and competitors, as well as forage across a wider habitat range.
Show less - Date Issued
- 2013
- Identifier
- WFE0000409, uwf:61157
- Format
- Document (PDF)
- Title
- TELOMERE ELONGATION IN REGENERATING TISSUES OF THE GREY STARFISH, LUIDIA CLATHRATA.
- Author
- Varney, Rebecca, Pomory, Christopher M., Janosik, Alexis M., Chung, Hui-Min, University of West Florida
- Abstract/Description
-
Regeneration of body tissues in starfish remains poorly understood despite centuries of study. In 2015 elongation of telomere sequences was documented in the asexually reproducing starfish Coscinasterias tenuispina, the first time such a phenomenon had ever been observed in somatic tissues. Here, telomere sequences were investigated in Luidia clathrata, a sexually reproducing species. Telomere elongation was confirmed in Luidia clathrata, after both arm injury and a simulated asexual split....
Show moreRegeneration of body tissues in starfish remains poorly understood despite centuries of study. In 2015 elongation of telomere sequences was documented in the asexually reproducing starfish Coscinasterias tenuispina, the first time such a phenomenon had ever been observed in somatic tissues. Here, telomere sequences were investigated in Luidia clathrata, a sexually reproducing species. Telomere elongation was confirmed in Luidia clathrata, after both arm injury and a simulated asexual split. Telomeres of juvenile starfish were consistently longer than those of adults. Telomerase expression was detected prior to injury as well as during regeneration, suggesting constitutive expression. As Luidia clathrata are not immediately related to Coscinasterias tenuspina, the presence of telomere elongation suggests that this ability may be common to all starfish.
Show less - Date Issued
- 2016
- Identifier
- WFE0000564, uwf:61193
- Format
- Document (PDF)
- Title
- THE EFFECT OF SHRIMP DENSITY AND ARTIFICIAL SEAGRASS DENSITY ON GROWTH AND PROXIMATE BODY COMPOSITION OF THE BROWN SHRIMP, FARFANTEPENAEUS AZTECUS (IVES, 1891) (CRUSTACEA:MALACOSTRACA: DECAPODA: PENAEIDEA).
- Author
- Ren, Alexander Kyung Joo, Pomory, Christopher M., Dantin, Darrin D., Darby, Philip C., University of West Florida
- Abstract/Description
-
Complex habitats benefit organisms by providing refuge from predators, foraging, and stress reduction. Juveniles are particularly vulnerable and rely on complex habitats as nurseries. Many studies have assigned nursery value to habitats based on juvenile abundances, rather than growth and recruitment to adult populations. Nearly all such studies have compared habitat types, rather than within habitat variation. The purpose of this study was to determine the potential value of different...
Show moreComplex habitats benefit organisms by providing refuge from predators, foraging, and stress reduction. Juveniles are particularly vulnerable and rely on complex habitats as nurseries. Many studies have assigned nursery value to habitats based on juvenile abundances, rather than growth and recruitment to adult populations. Nearly all such studies have compared habitat types, rather than within habitat variation. The purpose of this study was to determine the potential value of different seagrass, submerged aquatic vegetation (SAV), densities as well as shrimp densities to growth of juvenile brown shrimp, Farfantepenaeus aztecus (Ives, 1891). Experiments in tanks examined effects of non-vegetated bottom (NVB) and artificial SAV densities and different shrimp densities on growth. Measurements included total length, dry weight, and body composition of protein, lipid, and carbohydrate. Presence and density of artificial SAV density did not result in greater growth or changes in body composition; however, individual growth and carbohydrate reserves decreased significantly with increasing shrimp density. While individual growth decreased, total biomass produced was greatest in tanks with high shrimp densities. While the value of SAV should not be reduced, it appears that the value of NVB to juvenile brown shrimp may have been ignored by previous studies.
Show less - Date Issued
- 2011
- Identifier
- WFE0000291, uwf:60964
- Format
- Document (PDF)
- Title
- VENOM TOXICITY AND BIOENERGETICS OF THE SPINE FROM ATLANTIC STINGRAY, DASYATIS SABINA.
- Author
- Enzor, Laura Ann, Bennett, Wayne A., Pomory, Christopher M., Ryals, Phillip E., University of West Florida
- Abstract/Description
-
Atlantic stingray, Dasyatis sabina, possess a venomous spine thought to be useful in defense. Anecdotal evidence as well as observations of stinging incidents in nature illustrate that these fish are reluctant to use the spine when threatened or attacked, and in cases where the spine is used, it is not an effective predator deterrent. Venomous systems have been shown to be metabolically expensive, raising the question of why stingrays invest in a system that is inadequate for defense. This...
Show moreAtlantic stingray, Dasyatis sabina, possess a venomous spine thought to be useful in defense. Anecdotal evidence as well as observations of stinging incidents in nature illustrate that these fish are reluctant to use the spine when threatened or attacked, and in cases where the spine is used, it is not an effective predator deterrent. Venomous systems have been shown to be metabolically expensive, raising the question of why stingrays invest in a system that is inadequate for defense. This study determines stingray venom toxicity (LC50) and quantifies metabolic costs associated with the venom delivery system. Acute toxicity tests determined a LC50 value of 0.018 mg protein·g fish-1 with the average protein content of 35.71 mg·mL venom-1. Respirometry determined that approximately 0.000162 kcal·g-1·h-1 are devoted to maintenance of venomous tissues and the spine. Caloric density of spines was measured using ballistic bomb calorimetry. The average number of kilo-calories per gram of spine weight was 0.238. Empirical and observational evidence from laboratory and field studies suggest that the spine may serve key roles in reproductive behavior and in establishing social hierarchies as well as defense.
Show less - Date Issued
- 2008
- Identifier
- WFE0000102, uwf:60849
- Format
- Document (PDF)