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- Title
- THE ARTIFICIAL REEF EFFECT OF WORLD WAR II ERA SHIPWRECKS IN THE NORTHERN GULF OF MEXICO.
- Author
- Morris, Nicole Marie Brown, Patterson, William F., Darby, Philip C., Snyder, Richard A., University of West Florida
- Abstract/Description
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Deepsea fishes and their associated habitats have not been well studied in the northern Gulf of Mexico (Gulf). Furthermore, little is know about whether fishes in the deep Gulf utilize shipwrecks as artificial reef habitat. The objective of this study was to examine the utilization of shipwrecks as habitat by fishes across a depth gradient in the northern Gulf. I examined community structure, diet, trophic structure using stable isotope values (13C, 15N, and 34S), and age of fishes associated...
Show moreDeepsea fishes and their associated habitats have not been well studied in the northern Gulf of Mexico (Gulf). Furthermore, little is know about whether fishes in the deep Gulf utilize shipwrecks as artificial reef habitat. The objective of this study was to examine the utilization of shipwrecks as habitat by fishes across a depth gradient in the northern Gulf. I examined community structure, diet, trophic structure using stable isotope values (13C, 15N, and 34S), and age of fishes associated with six World War II era shipwrecks ranging in depth from 87 to 1,964 m. Statistical analysis of community structure estimates revealed significant differences existed among wreck sites (ANOSIM: p 0.001) and among sample locations within sites (ANOSIM: p 0.001). At the three shallowest sites, reef- or structure-associated fishes were predominant over wreck sites. Fish communities over deep wrecks were similar to those away from wrecks and consisted mostly of halosaurs (Family: Halosauridae), cusk eels (Order: Ophidiiformes), grenadiers (Family: Macrouridae), and eel (Family: Anguilliformes) species, listed in order from highest to lowest relative abundance. Diet of fishes was determined by analysis of gut contents (n = 107) and trophic position was further clarified by analysis of muscle stable isotope values (n = 79). Results revealed a range of trophic levels and sources of production as benthic, pelagic, or chemosynthetic. At the two shallowest sites, 13C and 15N values among fishes indicated a range in feeding from planktivores to piscivores, and 34S values indicated a range in benthic versus pelagic prey. Stable isotope values among fishes at the third shallowest site indicated little difference in trophic levels and a pelagic source of production. At the three deepest sites, 13C and 15N values indicated feeding at middle trophic levels, and 34S values indicated a pelagic source of production. A total of 97 otolith sections (84 adults and 13 juveniles) were examined. On the two shallowest wreck sites, fish tended to be larger at age and younger overall than fishes on deeper wreck sites. Results from this study provide insight into the ecological function of shipwrecks as large artificial reefs along a depth gradient. The artificial reef affect of shallow wreck sites was apparent, but for shipwrecks below 1,500 m, no artificial reef effect was observed for fishes.
Show less - Date Issued
- 2007
- Identifier
- WFE0000067, uwf:60700
- Format
- Document (PDF)
- Title
- SPATIAL PATTERNS OF PHYTOPLANKTON AND PERIPHYTON GROWTH AS INDICATORS OF ESTUARINE CONDITION IN ESCAMBIA BAY, FLORIDA.
- Author
- Wagner, Matthew Earl, Snyder, Richard A., Caffrey, Jane M., Lepo, Joe E., University of West Florida
- Abstract/Description
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Periphyton and phytoplankton responses along the salinity gradient and in depth profiles of Escambia Bay, FL, were compared over a sampling period covering two summer seasons. Periphyton accumulation ranged from 0 to 54 µg Chl a / dm2, and phytoplankton biomass ranged from 1.5 to 73 µg Chl a / L. Horizontal periphyton spatial patterns indicated distribution of bioavailable nutrients differently than phytoplankton. Maximum growth of periphytic and planktonic microalgae did not occur at the...
Show morePeriphyton and phytoplankton responses along the salinity gradient and in depth profiles of Escambia Bay, FL, were compared over a sampling period covering two summer seasons. Periphyton accumulation ranged from 0 to 54 µg Chl a / dm2, and phytoplankton biomass ranged from 1.5 to 73 µg Chl a / L. Horizontal periphyton spatial patterns indicated distribution of bioavailable nutrients differently than phytoplankton. Maximum growth of periphytic and planktonic microalgae did not occur at the same location in the estuary. This dissimilarity in spatial distribution was directly related to hydrographic conditions. Periphyton appeared to be more limited by total Nitrogen in the water than phytoplankton which was more dependent on total and dissolved Phosphorous. Vertical profiles showed that water chemistry not light availability controlled microalgal distribution, with the highest biomass accumulating at the freshwater/seawater interface. River discharge accounted for the majority of spatial and temporal variability of physical and nutrient dynamics in Escambia Bay estuary, and affected the location of the estuarine turbidity maximum and the phytoplankton chlorophyll maximum. This study presents evidence that analyzing periphyton growth at fixed locations provides the means to examine integrated nutrient loading patterns unconstrained by hydrodynamics. The combination of periphyton response measures with conventional measurements of the water column created a different view of the overall ecosystem status of Escambia Bay.
Show less - Date Issued
- 2006
- Identifier
- WFE0000010, uwf:60738
- Format
- Document (PDF)
- Title
- THE EFFECTS OF HUMAN AND CLIMATIC IMPACTS ON SEDIMIENT NITROGEN DYNAMICS IN ESCAMBIA BAY, FLORIDA.
- Author
- Smith, Kristin Anne, Caffrey, Jane M., Jeffrey, Wade H., Snyder, Richard A., University of West Florida
- Abstract/Description
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Potential nitrification rates and benthic flux measurements (NO2-+NO3-, NH4+, DIP, DSi, and SOC) were measured during the fall of 2005 at 12 different sites in Escambia Bay, Florida. Escambia Bay is a highly productive estuary whose major environmental problems include urban and agricultural runoff and point source discharges. A significant industrial spill occurred in 1969 when Monsanto Industrial Plant contaminated the bay with polychlorinated biphenyls (PCBs), which are still present in...
Show morePotential nitrification rates and benthic flux measurements (NO2-+NO3-, NH4+, DIP, DSi, and SOC) were measured during the fall of 2005 at 12 different sites in Escambia Bay, Florida. Escambia Bay is a highly productive estuary whose major environmental problems include urban and agricultural runoff and point source discharges. A significant industrial spill occurred in 1969 when Monsanto Industrial Plant contaminated the bay with polychlorinated biphenyls (PCBs), which are still present in the sediment over 40 years later. While PCB effects on marine life are well documented, much less is known of its effects on sediment nitrogen dynamics. Due to the sensitivity of nitrifying bacteria, PCBs were hypothesized to inhibit potential nitrification rates, but this study found no trend between PCB content and potential nitrification rates. In addition to anthropogenic effects, climatic impacts, such as two hurricanes, have affected the bay in recent years. Benthic fluxes from 2005 were compared to prestorm flux data and no significant long term storm effects were found. Potential nitrification rates from 2005 were compared to prestorm 2004 potential nitrification rates and significant differences were seen at the shallow site, but not at the deeper site.
Show less - Date Issued
- 2006
- Identifier
- WFE0000008, uwf:60749
- Format
- Document (PDF)
- Title
- PHOSPHATIDYLINOSITOL SYNTHASE OF TETRAHYMENA: UTILIZATION OF INOSITOL ISOMERS IN THE HEADGROUP EXCHANGE REACTION.
- Author
- Riggs, Bridget May, Ryals, Phillip E., Fox, Theodore C., Snyder, Richard A., University of West Florida
- Abstract/Description
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Phosphatidylinositol synthase [CDP-diacylglycerol: myo-inositol 3-phosphatidyltransferase, E.C. 2.7.8.11] is present in all eukaryotic cells and some bacterial cells. Predominantly found on the cytoplasmic side of the endoplasmic reticulum, this bifunctional enzyme catalyzes the de novo synthesis of phosphatidylinositol from cytidine diphosphate-diacylglycerol and myo-inositol. The enzyme also catalyzes a headgroup exchange reaction wherein the inositol headgroup of phosphatidylinositol is...
Show morePhosphatidylinositol synthase [CDP-diacylglycerol: myo-inositol 3-phosphatidyltransferase, E.C. 2.7.8.11] is present in all eukaryotic cells and some bacterial cells. Predominantly found on the cytoplasmic side of the endoplasmic reticulum, this bifunctional enzyme catalyzes the de novo synthesis of phosphatidylinositol from cytidine diphosphate-diacylglycerol and myo-inositol. The enzyme also catalyzes a headgroup exchange reaction wherein the inositol headgroup of phosphatidylinositol is exchanged for a different molecule of inositol. Headgroup exchange activity associated with phosphatidylinositol synthase from the protist Tetrahymena was investigated to establish whether isomers of inositol other than myo-inositol are suitable substrates. This investigation revealed that eight of the nine isomers of inositol examined were used as substrates in the headgroup exchange reaction. Furthermore, cytidine monophosphate was shown to be necessary for maximal headgroup exchange activity. These data provide evidence for a mechanism by which novel phosphatidyl-non-myo-inositols can be formed in vivo.
Show less - Date Issued
- 2006
- Identifier
- WFE0000030, uwf:60755
- Format
- Document (PDF)
- Title
- PERSISTENCE OF MOLECULAR INDICATORS FOR FECAL POLLUTION IN ENVIRONMENTAL WATERS, DEMONSTRATED IN MESOCOSMS USING A METHOD THAT DISTINGUISHES LIVE FROM DEAD MICROORGANISMS.
- Author
- Kennedy, Elizabeth Marie, Lepo, Joe E., Harwood, Valerie J., Jeffrey, Wade H., Snyder, Richard A., University of West Florida
- Abstract/Description
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Polymerase chain reaction (PCR) methods to detect indicators of fecal contamination are more rapid and specific than current government-recommended culture-based methods. However, PCR does not distinguish among live cells, dead cells or extracellular DNA. Propidium monoazide (PMA) is a DNA-binding dye that only permeates membrane-compromised (dead) cells. Once inside a dead cell, it binds DNA, preventing subsequent PCR amplification, allowing for PCR detection of only live cells. I used PMA...
Show morePolymerase chain reaction (PCR) methods to detect indicators of fecal contamination are more rapid and specific than current government-recommended culture-based methods. However, PCR does not distinguish among live cells, dead cells or extracellular DNA. Propidium monoazide (PMA) is a DNA-binding dye that only permeates membrane-compromised (dead) cells. Once inside a dead cell, it binds DNA, preventing subsequent PCR amplification, allowing for PCR detection of only live cells. I used PMA coupled with quantitative PCR (qPCR) to compare persistence of live human-associated Bacteroidetes (HB) and Methanobrevibacter smithii to dead HB and M. smithii and their extracellular DNA. The HB qPCR signal was detected for 5 to 6 days (d) in mesocosms and was unaffected by PMA treatment. Thus, HB DNA, detected by PCR, was due to live bacteria and would indicate recent human fecal contamination if present in natural water. In contrast, the M. smithii qPCR signal persisted the entire study without PMA treatment but only 5 to 6 d with PMA treatment. Thus, although live M. smithii decreased in the mesocosms, its DNA persisted. Thus, M. smithii DNA, as detected by PCR, could be due to live cells, dead cells or extracellular DNA, leading to false indication of fecal contamination.
Show less - Date Issued
- 2011
- Identifier
- WFE0000274, uwf:60885
- Format
- Document (PDF)
- Title
- RESPONSES IN BACTERIOPLANKTON PRODUCTION AND COMMUNITY STRUCTURE AFTER EXPOSURE TO OIL AND DISPERSANT IN THE NORTHEASTERN GULF OF MEXICO.
- Author
- Houghton, Katelyn Ashley, Jeffrey, Wade H., Lepo, Joe E., Snyder, Richard A., University of West Florida
- Abstract/Description
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The Deepwater Horizon Oil Spill in 2010 significantly impacted the planktonic ecosystem of the northern Gulf of Mexico. A key element of this ecosystem is the bacterioplankton. They are the base to the food web and were the primary agents of oil degradation. It has been hypothesized that exposure to oil and or dispersants may change microbial community structure by selecting for those strains capable of utilizing oil carbon while selecting against others by toxic effects of oil and or...
Show moreThe Deepwater Horizon Oil Spill in 2010 significantly impacted the planktonic ecosystem of the northern Gulf of Mexico. A key element of this ecosystem is the bacterioplankton. They are the base to the food web and were the primary agents of oil degradation. It has been hypothesized that exposure to oil and or dispersants may change microbial community structure by selecting for those strains capable of utilizing oil carbon while selecting against others by toxic effects of oil and or dispersants. To view spatial and temporal variability in bacterioplankton community response, surface and near bottom water samples were collected at two sites, offshore Choctawhatchee Bay, Florida, in winter (December 2012) and summer (June 2013). Bioassays were performed on 1 L water samples amended with oil, oil and Corexit, and Corexit alone, and compared to an un-amended control. Samples were incubated at in situ temperatures for two days in the dark and 16S rRNA genes were amplified and sequenced. Community structure shifts and production changes were associated mostly with the oil treatment, while Corexit alone had the smallest effect. Trends for community response were more significantly influenced by collection site parameters, namely season and depth, than by treatments.
Show less - Date Issued
- 2015
- Identifier
- WFE0000481, uwf:61118
- Format
- Document (PDF)
- Title
- SPATIAL AND TEMPORAL VARIATIONS IN THE COMMUNITY STRUCTURE OF MARINE ARCHAEA IN THE NORTHEASTERN GULF OF MEXICO.
- Author
- Tominack, Sarah Anne, Snyder, Richard A., Moss, Joseph A., Riesenfeld, Christian S., Richardson, Terry D., Jeffrey, Wade H., University of West Florida
- Abstract/Description
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Archaea, once thought to solely inhabit extreme environments, are now known to be widespread and have major roles in biogeochemical cycling. Archaea are known to utilize refractory compounds as an energy source and compete with bacteria in the open ocean for labile, often limiting, nutrients. In the Gulf of Mexico the BP Deepwater Horizon oil well failure (2010) highlighted the need to better understand basic physical, chemical, and biological dynamics of the North Eastern Gulf of Mexico (NE...
Show moreArchaea, once thought to solely inhabit extreme environments, are now known to be widespread and have major roles in biogeochemical cycling. Archaea are known to utilize refractory compounds as an energy source and compete with bacteria in the open ocean for labile, often limiting, nutrients. In the Gulf of Mexico the BP Deepwater Horizon oil well failure (2010) highlighted the need to better understand basic physical, chemical, and biological dynamics of the North Eastern Gulf of Mexico (NE GoM). Through 16S rRNA clone library analysis, this study characterized the spatial and temporal dynamics of archaeal communities on the Northwest Florida Shelf in the NE GoM. In addition, patterns in physicochemical parameters were examined and relationships between Archaea and the environment in the NE GoM explored. Four main archaeal assemblages were observed: a seasonally independent near coastal assemblage, a seasonally dependent epipelagic assemblage, a seasonally independent mesopelagic assemblage, and a unique seasonally independent sediment assemblage. The main environmental factors associated with archaeal community structure in the water column were nutrients and salinity, but no environmental factors measured accounted for variability in sediment archaeal communities.
Show less - Date Issued
- 2015
- Identifier
- WFE0000492, uwf:61130
- Format
- Document (PDF)
- Title
- TAXONOMIC AND METABOLIC CHARACTERIZATION OF BACTERIA ISOLATED FROM GULF OF MEXICO SEDIMENTS AFFECTED BY THE DEEPWATER HORIZON OIL SPILL.
- Author
- Davis, Bryan David, Lepo, Joe Eugene, Snyder, Richard A., Jeffrey, Wade H., Riesenfeld, Christian, University of West Florida
- Abstract/Description
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Recent studies of microbial response to the BP Deepwater Horizon oil spill have relied on non-culture based molecular biological tools for community structure analyses. To complement these studies, we enriched and isolated bacteria that utilize petroleum hydrocarbons as their sole C-source from sediments within the zone of impact. Deep-sea and near-shore sediments collected along a transect crossing the well-head of the Gulf of Mexico (GoM) BP oil spill were stored at 4C. Homogenized...
Show moreRecent studies of microbial response to the BP Deepwater Horizon oil spill have relied on non-culture based molecular biological tools for community structure analyses. To complement these studies, we enriched and isolated bacteria that utilize petroleum hydrocarbons as their sole C-source from sediments within the zone of impact. Deep-sea and near-shore sediments collected along a transect crossing the well-head of the Gulf of Mexico (GoM) BP oil spill were stored at 4C. Homogenized sediments were inoculated into Bushnell-Haas broth containing n-hexadecane, a PAH mix, and artificially weathered crude oil. Enrichments were shaken at 25C until turbid, then streaked to trypticase-soy agar. Unique colonies inoculated to sole C-source (phenanthrene or n-hexadecane) media ensured ability to grow on those substrates. In total, 138 strains have been isolated and maintained. The 16S rRNA genes of isolates were PCR amplified and sequenced, elucidating 14 genera from bacterial phyla Actinobacteria, Firmicutes, and Proteobacteria (all of which were within Class Gammaproteobacteria). Selected strains have been characterized using standard microbiological staining and testing. Many of our isolates represent bacterial taxa known to contain hydrocarbon degraders; individual isolates have been confirmed in our laboratory as presumptive hydrocarbon degraders.
Show less - Date Issued
- 2014
- Identifier
- WFE0000461, uwf:61131
- Format
- Document (PDF)
- 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
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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
- TEMPORAL ANALYSIS OF BACTERIAL COMMUNITY STRUCTURE IN THE NORTH EASTERN GULF OF MEXICO.
- Author
- Knight, Katelyn T., Jeffrey, Wade H., Caffrey, Jane M., Snyder, Richard A., University of West Florida
- Abstract/Description
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Bacteria are found in all oceans around the globe and dominate marine processes because of their abundance and contribution to biogeochemical cycles. Resource availability and environmental parameters are both key factors in determining bacterioplankton growth and community structure. Understanding temporal changes in the microbial community structure in the Gulf of Mexico has the potential to shed new light on the dynamics of energy transfer and organic processing. A two-year seasonal study...
Show moreBacteria are found in all oceans around the globe and dominate marine processes because of their abundance and contribution to biogeochemical cycles. Resource availability and environmental parameters are both key factors in determining bacterioplankton growth and community structure. Understanding temporal changes in the microbial community structure in the Gulf of Mexico has the potential to shed new light on the dynamics of energy transfer and organic processing. A two-year seasonal study was conducted at a station 40 km south of Choctawhatchee Bay on the Florida Shelf in the Northeast Gulf of Mexico. A total of 31 water column samples were collected from surface and bottom waters (~90 m) and mid-water deep chlorophyll maxima, when present, at 12 different time points. In addition to microbial diversity, chemical, physical, and biological environmental parameters such as bacterial production, nutrients, temperature, salinity, chlorophyll a, and bacterial counts were also taken. 16S rRNA clone libraries generated 2,160 high quality clones that were used for community analysis. 535 OTUs were obtained at 97% similarity. Samples were analyzed in three different categorical groupings: all OTUs, all OTUs grouped together at order level, and OTUs without dominant taxa. Environmental patterns were seen to correlate directly with seasonal changes; however, community structure was independent of seasonal trends. Depth, nutrients, and salinity were seen to have a slight influence on the community structure. This shows that no single parameter is driving the community structure, but rather the community structure is the result of complex interactions between many factors.
Show less - Date Issued
- 2018
- Identifier
- WFE0000619, uwf:61281
- Format
- Document (PDF)
