Texas A&M University – Corpus Christi
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Effect of Temporarily Opening and Closing the Marine Connection of a River Estuary
Get PDFThe lower Rio Grande is a river-dominated estuary that serves as the border between Texas, USA, and Tamaulipas, Mexico.
River estuaries encompass the section of the river influenced by tidal exchange with the Gulf of Mexico, but the connection with the Rio Grande is intermittent and can be temporarily open or closed. During the 4.8-year study period, the river
mouth was closed 30% of the time, mostly during average or dry climatic conditions, with the temporary closing of the river
mouth being linked to hydrology. When the Rio Grande estuary is closed, salinity is low (1.5 psu compared to 4.8 psu when
open), nitrate plus nitrite are low (4.4 μM compared to 31.5 μM when open), and ammonium is high (9.6 μM compared to
4.3 μM when open), but chlorophyll is similar (20 μg/L compared to 21 μg/L when open). Benthic macrofaunal abundance
and biomass are higher when the river mouth is closed: 16,700 individuals m−2 and 3.3 g m−2 compared to 8800 individuals
m−2 and 2.4 g m−2 when the Rio Grande river mouth is open. Benthic macrofaunal community structure is divided into two
groups: chironomid larvae and Oligochaeta dominated when the river mouth was closed, whereas polychaetes Mediomastus
ambiseta and Streblospio benedicti dominated when the river mouth was open. The implications of these results for managing freshwater flows are that the open and closed conditions each have a characteristic benthic macrofaunal community that
is strongly influenced by system hydrology
Photograph of a two sail boats in Corpus Christi, Texas
No full textPhotograph of a two sail boats in Corpus Christi, Texa
Tracking bottlenose dolphin movement and behavior in the Corpus Christi ship channel
No full textPort Corpus Christi and Port Aransas, Texas, have undergone considerable infrastructure and oil exportation growth over the past 40 years. As humans continue to transform and exploit these coastal marine habitats, understanding dolphin and vessel interactions in the area is vital to improve conservation and management practices. As dolphins increased diving intervals and avoidance behavior in the presence of vessels, protecting marine mammals in areas of high vessel activity is urgent. To test the hypothesis that the movement patterns and behaviors of free-swimming bottlenose dolphins (Tursiops truncatus) are altered by vessel presence and size near Port Aransas, a shore-based digital theodolite is being used. Dolphin behavioral state and movement are analyzed in response to vessel activity. Distance between dolphin positions and habitat features are being calculated in ArcGIS Pro. Large vessels may elicit social and travel behavioral states as dolphins rode on the bows of most large tankers and cargo carriers. Dolphins mill and forage along channel banks and near the ferry crossing, suggesting that physical structures of concrete seawalls and mixing currents from vessel activity are utilized by dolphins to capture prey. In the morning and afternoon, dolphins oriented along the channel perimeter against the current flow with no positional changes in movement, indicating that tides may influence this population’s movement and behavior patterns. Understanding behavioral associations with diverse microhabitats in the Port Aransas area is crucial to conserve critical environments utilized by dolphins
Physical properties of dicarboxylated amino acid based surfactants in presence of diamine alkane counterions
No full textSurfactants are being examined for many different fields such as chemical, medical, cosmetics, and phar- maceutical applications. Surfactants consist of two regions a hydrophobic and a hydrophilic region. The hydrophobic region is the head in most surfactants, while the hydrophilic region is the tail. Surfactants are dynamic molecules and able to form micelles. The micelles form when the hydrophobic region aggregates together and forms different shapes. The concentration at which micelles are formed is called the critical micelle concentration (CMC). The CMC is the lowest concentration needed for the surfactants to form mi- celles. Many different types of surfactants can be created. The surfactants that were examined consisted of dicarboxylated amino acid groups (glutamic and aspartic) with a 11 and 13 caron chain hydrophobic tails. The CMC of these surfactants were measured in presence of 1,2 diamino ethyl, 1,3 diaminopropane, 1,4 diaminobutane, 1,5 diaminopentane and 1.6 diaminohexane. The effects of the different amino acids, tail structures, and counterions were tested by comparing the CMC values of the solution. The CMC was measured using the change in solution conductivity at different surfactant concentrations. Preliminary re- sults indicated that the hydrophobic chain length and the counterion type significantly effects aggregation behavior of the dicarboxylated amino acid surfactants in solution
Jessie Elizabeth Heard Power
No full textPortrait of Jessie Elizabeth Heard Power, wife of James F. Power and mother of Audre
Photograph of a portion of the Broadway Bluff Balustrade Improvement
No full textPhotograph of a portion of the Broadway Bluff Balustrade Improvemen
Family Returning to North Beach
No full textFamily Returning to North Beach returning after the hurricane scar
Photograph of Mechee Taken in Backyard at home before houses were removed.
No full textPhotograph of Mechee Taken in Backyard at home before houses were removed