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Distribution, condition, and growth of newly settled southern flounder (Paralichthys lethostigma) in the Galveston Bay Estuary, TXGlass, Lindsay Ann 16 August 2006 (has links)
Several flatfish species including southern flounder (Paralichthys lethostigma)
recruit to estuaries during early life. Therefore, the evaluation of estuarine sites and
habitats that serve as nurseries is critical to conservation and management efforts. I used
biochemical condition and growth measurements in conjunction with catch-density data
to evaluate settlement sites used by southern flounder in the Galveston Bay Estuary
(GBE). In 2005, beam-trawl collections were made in three major sections of the GBE
(East Bay, West Bay, Galveston Bay), and three sites were sampled in each bay. Within
each sampling site, replicate collections were taken from 1) the marsh edge, 2) an
intermediate zone, and 3) the open bay. The average size of southern flounder collected
was between 12 and 19 mm standard length, and peak densities occurred in January and
February. Catch data indicated that numeric densities of southern flounder were
significantly greater in East Bay (2.75 per 100 m2) than in West Bay (0.45 per 100 m2) or
in Galveston Bay (0.91 per 100 m2). Habitat-specific variation in density was not found.
Otolith-based estimates of age indicated that the majority of southern flounder collected
were 35-45 days old and derived from early December to early January hatch-dates.
Growth rate differences were negligible across bays and habitats, with the average
growth rate being 0.40 mm/day (range 0.21-0.76 mm/day). RNA:DNA ratios indicated
that newly settled southern flounder in the GBE were in relatively high condition. Habitat-specific differences in RNA:DNA ratios were not observed; however, ratios were
significantly lower in West Bay (average 8.0) than in East Bay (average 9.5) or in
Galveston Bay (average 9.8), suggesting the condition of new recruits may vary across
the GBE. Findings from this study indicate that southern flounder use a variety of
habitats within the GBE during early life, and survival and recruitment success appear
favorable regardless of settlement site. As a result, recruitment success of southern
flounder may be less a function of the quality of nursery sites/habitats within the GBE
than of other factors (e.g., larval supply to the estuary).
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Sonar imaging of bay bottom sediments and anthropogenic impacts in Galveston Bay, TexasMaddox, Donald Shea 25 April 2007 (has links)
Knowledge of surface sediment distribution in Galveston Bay is important because it
allows us to better understand how the bay works and how human activities impact the
bay and its ecosystems. In this project, six areas of bay bottom were surveyed using
acoustic techniques to make maps of bay bottom types and to investigate the types and
extent of anthropogenic impacts. A total of 31 km2 was surveyed in six areas, one in
Bolivar Roads (6.1 km2), one near Redfish Bar (3.1 km2), two in East Bay (12 km2), one
southeast of the Clear Lake entrance (5.3 km2), and one in Trinity Bay (4.3 km2). Sidescan
sonars (100 kHz and 600 kHz) were used to image the bay bottom, and a chirp
sonar (2-12 kHz) was used to image subsurface sediment layers and bottom topography.
In the side-scan records, objects as small as a few meters in extent were visible, whereas
the chirp sonar records show a vertical resolution of a few tens of centimeters. The sidescan
images display strong backscatter in some areas due to coarse sediments in addition
to weak backscatter in areas of fine sediment. The bay bottom was classified using three
levels of sonar backscatter ranging from high to low. Areas of differing sonar
backscatter intensity were sampled with cores and grab-samples. High backscatter
corresponded to coarse shell debris and oyster reefs, medium backscatter corresponded to a sand-silt-shell mixture, and low backscatter corresponded to silty loam. Chirp sonar
records were classified as one of nine different bottom reflection types based on changes
in amplitude and stratigraphy. Parallel, layered sediments are seen filling the bay valley
and resting atop a sharp contact at which the acoustic signal fades out. Along the flanks
of the valley fill the acoustic response revealed an absent or weakly laminated
stratigraphy, whereas areas of high oyster productivity produced mounds, strong surface
returns, and strong, shallow subsurface reflectors surrounding current oyster reefs.
Anthropogenic features imaged with the sonar included sediment disruptions, such as the
ship channels, dredge holes, gouges, and trawl marks, as well as debris, such as
submerged boats, pipes, and unidentified objects.
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Flow around a dredge spoil island in a shallow estuary during peak tidal currentsChristiansen, David Aaron 24 March 2014 (has links)
A vessel-mounted ADCP study focusing on channel-scale flow patterns in Galveston Bay near the Houston Shipping Channel and Mid-Bay Island is described. Winds of 5-7 m/s at 215-230◦ from N were present during data collection. For both peak ebb and flood conditions, the tidal circulation forced flow in a direction opposing the wind, perhaps due to a large-scale flow divergence forced by Mid-Bay Island. The strongest such currents were measured closest the island.
During peak flood flow, the shape of the along-channel velocity profile for the open water upwind of the channel at Mid-Bay Island indicated uniform flow, and the salinity profile indicated a well-mixed water column. The near-island along- channel velocity profile showed a near-linear trend, and the salinity profile indicated a stratified water column. This suggested that the stratification had some effect the velocity profile shape, but further research is needed to better quantify this effect.
During peak ebb flow, the near-island along-channel velocities were highly variable with respect to the mean velocity, indicating an area of active turbulence. Salinity profiles collected in the open water and near-island both showed stratification, something that was not seen during flood conditions.
Differences in observations between flood and ebb flows can possibly be attributed to the survey location with respect to the chain of dredge spoil islands. During flood flows Mid-Bay Island is the first of the islands, and the flows surrounding the island may part of a developing horizontal boundary layer. During ebb flows the island is last in the chain relative to the direction of flow, and therefore the surrounding flows are well back from the leading edge of a horizontal boundary layer. / text
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Sea-ing Blue: Community Responses to an Eco-Award in Galveston, TexasButler, Kristin 08 1900 (has links)
The Blue Flag program is a French international eco-award for beaches, marinas, and tour boats. With a set of 33 criteria required for obtaining the award, the Blue Flag program has sites all over the world, but none in the United States. The American Shore and Beach Preservation Association (ASBPA) sought to change that and provided an opportunity for locations in the U.S. to apply for the award. One of those applicants was the Galveston Island Park Board of Trustees in Galveston, Texas. This thesis focuses on data obtained for the park board through a survey to determine beachgoer support and interest in the Blue Flag program. Data was collected through the use of a survey and ad hoc interviews during the summer of 2021. Examined through various theoretical lenses, the data was analyzed to determine its impacts on the local community, and its relationship with other historical conservation projects. The results for this project were provided through a paper report and presentation on the findings to the client and presented at the ASBPA National Coastal Conference in October of 2021.
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Using Geographic Information Systems for the Functional Assessment of Texas Coastal Prairie Freshwater Wetlands Around Galveston BayEnwright, Nicholas 05 1900 (has links)
The objective of this study was to deploy a conceptual framework developed by M. Forbes using a geographic information system (GIS) approach to assess the functionality of wetlands in the Galveston Bay Area of Texas. This study utilized geospatial datasets which included National Wetland Inventory maps (NWI), LiDAR data, National Agriculture Imagery Program (NAIP) imagery and USGS National Land Cover data to assess the capacity of wetlands to store surface water and remove pollutants, including nitrogen, phosphorus, heavy metals, and organic compounds. The use of LiDAR to characterize the hydrogeomorphic characteristics of wetlands is a key contribution of this study to the science of wetland functional assessment. LiDAR data was used to estimate volumes for the 7,370 wetlands and delineate catchments for over 4,000 wetlands, located outside the 100-yr floodplain, within a 2,075 square mile area around Galveston Bay. Results from this study suggest that coastal prairie freshwater wetlands typically have a moderate capacity to store surface water from precipitation events, remove ammonium, and retain phosphorus and heavy metals and tend to have a high capacity for removing nitrate and retainremove organic compounds. The results serve as a valuable survey instrument for increasing the understanding of coastal prairie freshwater wetlands and support a cumulative estimate of the water quality and water storage functions on a regional scale.
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Opening the closed shop: the Galveston Longshoremen's Strike, 1920-1921Abel, Joseph Anthony 17 February 2005 (has links)
Beginning in March of 1920, the Galveston coastwise longshoremens strike against the Morgan-Southern Pacific and Mallory steamship lines was a pivotal moment in the history of organized labor in Texas. Local and statewide business interests proved their willingness to use the state apparatus by calling on Governor William P. Hobby and the Texas National Guard to open the Port of Galveston. Despite this, the striking dockworkers maintained the moral support of many local citizens from a variety of social classes, including small merchants and officials of the Galveston municipal government. By February of 1921, however, the segregated locals representing the striking longshoremen had fallen victim to the divisive racial tactics of the shipping companies, who implemented the open-shop policy of non-discrimination in hiring on their docks. Further demonstrating the capital-state alliance, the Texas legislature passed Governor Hobbys notorious Open Port Law in October 1920, making it virtually illegal for dockworkers and others to engage in strikes deemed harmful to commerce. This legislation and the nearly yearlong strike not only destroyed the coastwise longshore unions in Galveston, but ushered in a decade of repression from which Texass organized labor movement did not recover for many years.
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Antecedent and anthropogenic influences on the Galveston Island shorefacePitkewicz, Jennifer Lynn 15 May 2009 (has links)
Galveston Island, Texas has been experiencing high rates of erosion in recent
years, spawning an interest in developing complex beach management programs.
However, before any effective management project can be implemented we must
understand all of the processes that control the shoreface. It is only recently that
scientists have begun to recognize the importance of the role that the geologic
framework plays on the coastal evolution of the shoreline. In this region, it is the
antecedent geology as well as the anthropogenic obstructions which are the key factors
controlling the formation of the modern shoreface. This study defines the extents to
which these antecedent and anthropogenic factors influence the shoreface as well as
refines the geologic interpretations offshore of Galveston Island. Using sidescan sonar,
CHIRP seismic sonar, multibeam bathymetry data and sediment cores, the shoreface and
subsurface geology were modeled. It was determined that the thickness, extent and
slope of the modern sediment in the nearshore environment is controlled by the
topography of the Beaumont Clay, a consolidated clay deposited during the Pleistocene. Anthropogenic obstructions, including the Galveston Seawall, groin and jetty system,
have changed the sediment transport patterns in the region and have created a system of
erosion and accretion not only along the shoreline, but for the entire length of the
shoreface.
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Response of Benthic Microalgal Community Composition at East Beach, Galveston Bay, Texas to Changes in Salinity and NutrientsLee, Alyce R. 2009 May 1900 (has links)
Benthic microalgal community composition on an ephemerally submerged sandflat at East Beach, Galveston Island, Texas was studied to determine the spatial and temporal variability of total biomass and community composition and its responses to experimental manipulations of two environmental factors (salinity and nutrients). Four field studies were conducted between August 2004 and February 2005. The community consisted of two major algal groups, diatoms, and cyanobacteria with two less abundant groups, green algae, and phototrophic bacteria. Spatial variability showed that patch sizes of 12 - 25 m were detected over larger scales with smaller scale (cm) patches of approximately 28 - 201 cm^-2 contained within the larger patches. The second study examined the spatio-temporal variability of BMA over a 21-month period in a 1,000 m^2 area. Sampling location and date explained a significant amount of the variability in the abundances of algal groups, which were positively correlated with the water content of the sediments and negatively correlated with temperature (sediment and water). All of the algal groups showed a seasonal pattern with higher abundances measured in the winter months and lower abundances found during the summer. BMA biomass (100 mg Chl a m^-2 or greater) maxima occurred at temperatures less than 22 degrees C and sediment water content greater than 15% (g water g sediment^-1).
BMA response to different salinities and nutrient (N+P) amended sediments was assessed in four bioassays conducted over a 6-month period (Aug. 2004, Oct. 2004, Dec. 2004, and Feb. 2005). In the salinity study, the treatments that were either 100% or partially diluted with deionized water had the lowest BMA biomass over all. Chlorophyll a and fucoxanthin were significantly affected by salinity with higher abundances found in salinities that averaged 15 with a preference for salinities greater than 22. Chlorophyll b was affected by salinity with higher abundances measured in the treatments with lowest salinity (DL and DI); and was affected by the time of year. This would suggest that this algal group prefers an environment with salinity less than 2 but can easily adapt to environments with higher salinities. BMA abundances were not significantly affected by the nutrient amended sediment, but were significantly affected by stations with higher water content, and during the cooler months (Dec. 2004 and Feb. 2005).
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A Rapid Assessment Method Examining the Ecological Health of Tidal Marine Wetlands in Galveston Bay, TexasStaszak, Lindsey Ann 2010 August 1900 (has links)
Wetlands are one of the most productive ecosystems in the world, housing diverse biota and serving important functions as nursery habitat and feeding grounds. However, nearly 70% of coastal wetlands, including 21% of the salt marshes in Texas, have been lost since 1950, due primarily to coastal development and declines in water quality. Restoration of wetlands is essential to reestablish lost functions, but there is no standard method to assess the ecological health of restored salt marshes in Texas. Numerous recent salt marsh restoration projects in Galveston Bay have made it an ideal model system to develop and implement an ecosystem health assessment, known as a rapid assessment method (RAM). In this study, I modified an established RAM, the Mid-Atlantic Tidal Fringe Assessment, to compare the ecological health of representative reference salt marshes to restored marshes around Galveston Bay.
I measured 14 biotic and abiotic characteristics at 12 restored and 6 reference sites around Galveston Bay, and then grouped those measurements into four functional groups: landscape/site characteristics, hydrology, wildlife habitat, and soil characteristics. I then developed a scoring system (minimum 0, maximum 100) to summarize the overall health of each site.
Most of the restored salt marshes in this study scored lower than reference marshes. The average reference site score was 81.8 and the average restored site score was 69.7. Functional group values for landscape/site characteristics, soil, and wildlife habitat were significantly lower in restored than in reference sites. In particular, restored sites had more hydrological modifications, more fill material, and fewer macrobenthos than reference wetlands.
The Galv-RAM effectively and efficiently identified restoration successes and weaknesses. With this information, management agencies can address restoration shortcomings by adapting management goals. The Galv-RAM will streamline monitoring protocols and facilitate long-term examination of restored wetland health. As a result, management decisions can be modified based on the scores received in different categories or variables to improve and or meet the goals of the project.
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Opening the closed shop: the Galveston Longshoremen's Strike, 1920-1921Abel, Joseph Anthony 17 February 2005 (has links)
Beginning in March of 1920, the Galveston coastwise longshoremens strike against the Morgan-Southern Pacific and Mallory steamship lines was a pivotal moment in the history of organized labor in Texas. Local and statewide business interests proved their willingness to use the state apparatus by calling on Governor William P. Hobby and the Texas National Guard to open the Port of Galveston. Despite this, the striking dockworkers maintained the moral support of many local citizens from a variety of social classes, including small merchants and officials of the Galveston municipal government. By February of 1921, however, the segregated locals representing the striking longshoremen had fallen victim to the divisive racial tactics of the shipping companies, who implemented the open-shop policy of non-discrimination in hiring on their docks. Further demonstrating the capital-state alliance, the Texas legislature passed Governor Hobbys notorious Open Port Law in October 1920, making it virtually illegal for dockworkers and others to engage in strikes deemed harmful to commerce. This legislation and the nearly yearlong strike not only destroyed the coastwise longshore unions in Galveston, but ushered in a decade of repression from which Texass organized labor movement did not recover for many years.
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