Larval recruitment is influenced by intrinsic biological traits (e.g. swimming behavior) and environmental factors. In this study, I examined the effects of environmental factors (e.g. light, temperature, salinity and pH) on the development of an intertidal keratose sponge from Peng-hu. The experiments included species identification, the observation of larval development, effects of environmental factors on larval choice and development. Based on morphological characters and the mitochondrial COI (cytochrome c oxidase subunit I) gene, the sponge is identified as Spongia ceylonensis which is viviparous. Sponge larva is a typical lecithotrophic, tufted parenchymella, about 500 £gm long and ovoid in shape. The mean swimming speed was 3.9 ¡Ó 0.6 sec/cm. Under natural light condition (3500 ¡V 6500 lux), planktonic stage was 5-6 hours. In the vertical dark/light choice experiments, larvae exhibited a negative phototaxis with larvae distributed in dark areas in all treatments except the light-treated group. A significant shorter time period for metamorphosis in the light-treated group than all other groups (all dark, upper-half dark and lower-half dark) (p < 0.0001) had been observed. Under various light gradients of single light source, i.e. fluorescent, non-UV, UVA, UVB or UVC light, larvae preferred in the darkest area. Under various light sources (fluorescent, non-UV, UVA, UVB and UVC lights) with the same intensity (220 ¡Ó 10 lux), there was no significant differences (p > 0.05) in the distribution of larvae. In all, larvae had strong dark preference and no preference on different light sources. Under various environmental gradients of each experimental factor (i.e. pH 6.5 ¡V 9.0; temperature: 20 ¡V 40¢J; silica: 0.5 ¡V 20.5 mg/L) in all light or all dark conditions, larvae showed no significant preference (p > 0.05). In salinities of 5, 15, 25 and 45 psu, some larvae had abnormal development as ball formation or dead. At pH 8.0 and 8.2, sponge juveniles developed better than the groups of pH 7.0¡B7.5¡B8.5 and 9.0. In addition, there was no significant difference in larval development (p > 0.05) under various silica concentrations (i.e. SiO2 0¡B2.5¡B5.0¡B7.5¡B10.0 mg/L).

Thesis (M. Phil.)--University of Hong Kong, 1982.

Future climate change has been the subject of considerable speculation with scientists called upon to predict timing, magnitude, and impact of these changes. The Pliocene Warm Period serves as the best-available, pre-modern analog to predicted climate changes, and Pliocene climate anomalies are examined as possible scenarios for future climate change. Comparing modern conditions to the mean climate state of the Pliocene is essential for better constrained predictions of future climate change, and seasonal paleoenvironmental records provide a data set more analogous to instrumental observations and thereby reducing the uncertainty in modeled climate changes. This study first examines the potential of large gastropod shells as a paleoclimate proxy. Specimens of Busycon sinistrum, active in winter, and Fasciolaria tulipa , active in the summer, were collected alive from Tampa Bay and St. Joseph Bay in the hope of establishing a multi-year record of seasonality. The δ18O time series of each shell were compared with predicted δ18O, based on local marine temperature variations, and both species cease shell growth during the winter months, despite opposing seasons of feeding activity. As none of the profiles provide information on winter environmental parameters, this sclerochronological system was replaced by work on pristine specimens of the scleractinian coral Siderastrea spp.  Seasonal δ18O and Sr/Ca time series from two Pliocene corals, collected from the Lower Pinecrest Member of the Tamiami Formation in southwest Florida, were used to calculate seawater δ18O variations. Inferred salinity in the Pliocene has a reversed seasonal pattern from that of modern annual salinity variations, and is interpreted to be a response to an increase in winter precipitation, a teleconnection of the Pliocene “Super El Niño.” Concentrations of variance in the typical ENSO frequency band are not apparent above the 95% confidence interval, suggesting that the Pliocene was dominated by a perennial, rather than an intermittent, El Niño-like state.  Further geochemical analyses from both Pliocene and Pleistocene Siderastrea spp. corals indicate a high nutrient nearshore marine environment in south Florida. Marine phosphates, inferred from P/Ca analyses, were significantly higher in the Pliocene Tamiami Fm. than in the Early Pleistocene Caloosahatchee and Bermont Fms, and the decline in nutrients preceded local extinction by > 0.5 Ma. Additionally, high-resolution P/Ca analyses of an individual coral reveal no evidence of seasonality required by a previously hypothesized upwelling-based nutrient delivery mechanism The Pliocene nearshore marine environment in southwest Florida was characterized by higher nutrients than in the Pleistocene and precipitation patterns similar to modern El Niño teleconnections.

Estuarine wetlands and salt marshes are fundamentally driven by variations in freshwater inflow. In semi-arid salt marshes, such as the Nueces River Delta, TX, the stochastic nature of freshwater inflow events exposes resident organisms to a wide range of environmental conditions. In this study, we investigate (1) the relative importance of environmental variables on porewater salinity and (2) determination of freshwater inflow needs based on the response of emergent plants to salinity variations. Porewater salinity variations were tracked on a continuous basis with deployed conductivity sensors and on a synoptic basis with soil water extracts. We found that spatial patterns of porewater salinity were characterized by a high degree of variability in creekbank areas (23.8 ± 7.68) relative to interior marsh areas (44.2 ± 3.4). Our observations were used to test a simple model capable of predicting porewater salinities based on environmental variables. Both empirical measurements and model simulations indicated that semiannual tides play a critical role in controlling porewater flushing from precipitation and freshwater inflow events. Estimation of freshwater inflow needs for the Nueces Delta proceeded in two steps. First, we examined the response of three common emergent plants species (Borrichia frutescens, Spartina alterniflora, and Salicornia virginica) to variations in salinity. The abundance of one species in particular (S. alterniflora) was tightly coupled to salinity variations whereby salinities exceeding 25 ± 5 resulted in dramatic declines in coverage. Next, the relationship between freshwater inflow and porewater salinity was examined with respect to the salinity “tolerance” of S. alterniflora. Estimated inflow needs based on maintenance of substantial (> 20%) S. alterniflora coverage was comparable to both previous inflow needs estimates and mean annual inflows observed over the course of the study. The results of this study suggest that S. alterniflora abundance provides a reliable indicator of overall estuarine hydrological condition in the Nueces Delta. / text

The effect of brine ionic composition on oil recovery was studied for a limestone reservoir rock at a high temperature. Contact angle, imbibition, core flood and ion analysis were used to find the brines that improve oil recovery and the associated mechanisms. Contact angle experiments showed that modified seawater containing Mg[superscript 2+] and SO4[superscript 2-] and diluted seawater change aged oil-wet calcite plates to more water-wet conditions. Seawater with Ca[superscript 2+], but without Mg[superscript 2+] or SO₄[superscript 2-] was unsuccessful in changing calcite wettability. Modified seawater containing Mg[superscript 2+] and SO₄[superscript 2-], and diluted seawater spontaneously imbibe into the originally oil-wet limestone cores. Modified seawater containing extra SO₄[superscript 2-] and diluted seawater improve oil recovery from 40% OOIP (for formation brine waterflood) to about 80% OOIP in both secondary and tertiary modes. The residual oil saturation to modified brine injection is approximately 20%. Multi ion exchange and mineral dissolution are responsible for desorption of organic acid groups which lead to more water-wet conditions. Further research is needed for scale-up of these mechanisms from cores to reservoirs. / text

Contaminated sediments are periodically subjected to resuspension processes during either storm events or due to dredging. In sediments, metals are often contained in insoluble low bioavailability forms. Upon resuspension, however, biogeochemical processes associated with the exposure to more oxic conditions may lead to transformation and release of the metals, giving rise to exposure and risk in the water column. Batch experiments suggested that oxidation of reduced species and corresponding pH decrease were the most importance processes controlling metals release upon sediment resuspension. A mathematical model was implemented to better understand the complex underlying biogeochemical reactions that affect metals release. The model described the metals dynamics and other inter-related important biogeochemical factors well and was successful at predicting the metals release from different sediment reported in the literature. Tidal and other cyclic variations in oxygen, pH and other relevant parameters in the overlying water may also lead to cyclic transformations and release of metals from surficial sediments. In simulated estuarine microcosm experiments, cyclic variations in pH and salinity due to freshwater/saltwater exchange were shown to lead to cyclic variations in metal release. Both pH and salinity were important factors controlling interstitial dissolved metals concentrations, however, in terms of freely dissolved metals concentrations, which have been considered to be more related with toxicity and bioavailability, pH was the single most important parameter. The mathematical model was extended to the conditions of the cyclic behavior in an estuary and successfully described metals release under such conditions. It is believed that the model can be used to predict the metals behavior in other sediments and conditions by model calibration with a similar experimental approach to that used in this study. / text

The focus of this study was the development of an improved correlation that more accurately quantifies the relationships between optimum salinity, optimum solubilization ratios, chemical formulation variables such as surfactant and co-solvent structures, and the EACN. Entrained in this study are improved correlations for co-solvent partition coefficients and correlations for the optimum salinity and solubilization ratio with EACN. Several trends in the oil-water partition coefficient were observed with the alcohol type (IBA and phenol), the number of ethylene oxide groups in the co-solvent, the EACN of the oil, temperature, and salinity. New EACN measurements were made using optimized formulations containing various combinations of primary surfactants, co-surfactants, co-solvents and alkali. The new EACN measurements ranged from 11.3 to 21.1. These new data significantly expand the total number of reliable EACN values available to understand and correlate chemical EOR formulation results. An improved correlation that more accurately quantifies the relationship between surfactant structure, co-solvents, oil, temperature, and optimum salinity was developed using a new and much larger high quality formulation dataset now available from studies done in recent years in the Center for Petroleum and Geosystems Engineering at the University of Texas at Austin. The correlation is useful for understanding the now very large number of microemulsion phase behavior experiments as well as the uncertainties associated with these data, and for suggesting new chemical structures to develop and test. / text

10 pp. / Introduction: Adult human beings may drink up to two liters/day (approx. two quarts/day) of fresh water to stay alive. However, we can consume up to two quarts/hour of water, depending on the level of activity, ambient temperature, and humidity conditions (Born 2013). We also need fresh water to cook with and to clean ourselves. About 40% of our food production depends on irrigation (UN Water 2013) using water with low salinity and other contaminants. Climate scientists project increasing temperatures and possibly less rainfall in the Southwest now and into the near future, see Extension Publication #AZ1458 (Artiola et al. 2008). Thus, climate change is likely to stress the limited water resources of Arizona and affect water quality by concentrating contaminants and stressing water-dependent environments. This publication presents brief summaries of the types of water sources, their water quality, and possible uses in Arizona. Since the types and amounts of constituents found in water, whether nutrients, pathogens, contaminants or pollutants, help determine its possible uses, it is necessary to measure water quality to determine treatment options for a given use. To assist in this task, we present a triangle-shaped diagram (Figure 8) which divides water quality into three major groups: Pathogens, Salinity, and Specific Contaminants, placing major water sources in relation to the three groups. Home and well owners can use this diagram as a general aid to evaluate various sources of water, determine their likely water quality, and identify appropriate uses for them.

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The area of secondarily salinized lands is increasing at a faster rate over time. Many irrigation districts around the world are shrinking as a result of secondarily salinized soils. This is resulting in crop yield losses. Irrigation practices with low drainage are intensifying this problem. Bioremediation of salinized soils with halophytes is one of the means of reversing this process. In these studies, we tested the growth and performance of four salt tolerant halophytes to varying levels of salinity. We analyzed the salt content of the plant tissues at different salinities, in order to determine how the plants' tissues reflect the increases in salinity. It was discovered that Allenrolfea occidentalis tolerates and grows well at higher salinities than the other plants tested. Furthermore, the concentration of salt in the aerial plant tissue was high and increased further in response to the external salt concentration. Halophytes such as A. occidentalis can be used to remediate abandoned salt affected lands and their biomass can have an added economic value. On the other hand, domestication of wild halophytes for agronomic purposes represents another opportunity to address the increasingly salinized soils and shortages of freshwater around the world. In these studies, we assessed the potential for improvement of an oilseed halophyte, Salicornia bigelovii, through selective breeding. We compared plant characteristics of S. bigelovii cultivars produced in breeding programs with wild germplasm in a green house common garden experiment. We concluded that S. bigelovii has sufficient genetic diversity among wild accessions and cultivars to support a crop improvement program to introduce desirable agronomic characteristics into this wild halophyte.