The Rio Grande cichlid (Herichthys cyanoguttatus) has been established in the Greater New Orleans Metropolitan Area (GNOMA) for at least 20 years. It is often the most common fish species in urban canals and has also been found in natural waterways outside of the GNOMA. The effects and potential for further spread of H. cyanoguttatus is uncertain. My research addressed how extensive the cichlids spread in the GNOMA, how H. cyanoguttatus interacted with L. macrochirus, a native fish, and what salinity tolerance this species has. Surveys on Lake Pontchartrain and in the GNOMA indicated that H. cyanoguttatus is well established in urban habitats. These surveys also indicate that H. cyanoguttatus has spread rapidly into Bayou Saint John and City Park in recent years and that H. cyanoguttatus populations were relatively unaffected by Hurricanes Katrina and Rita. There is little evidence that H. cyanoguttatus has become established outside of the GNOMA, but this lack of persistence cannot be explained by abiotic variables I measured. Salinity may be a factor and this was measured in growth trials of H. cyanoguttatus. Salinities up to 16 ppt, however, had no significant effect on H. cyanoguttatus growth. Interspecific behavioral experiments were conducted to examine potential biotic interactions with native fish species. Prior resident trials indicated that H. cyanoguttatus was aggressive whether holding territory or not, and that native bluegill (Lepomis macrochirus) was only aggressive while holding territory. Feeding experiments were performed to examine biotic interactions between H. cyanoguttatus and L. macrochirus. Lepomis macrochirus grew faster than H. cyanoguttatus when inter- and intraspecific trials were compared; however, no significant growth differences were seen when trials were structured with L. macrochirus as prior residents. The major findings of my research are a high salinity tolerance of H. cyanoguttatus, a potential mechanism for H. cyanoguttatus affecting native fishes through aggression as residents and invaders, and the presence of H. cyanoguttatus throughout the GNOMA, before and after the hurricanes.

A concentração de sais na água é um dos principais aspectos a ser observado para se definir uma estratégia de manejo da irrigação, podendo levar a prejuízos pela salinização do solo, com conseqüente redução do rendimento das culturas. Visto que culturas tolerantes à salinidade apresentam maiores teores foliares de certos nutrientes, então a adubação em culturas sensíveis poderia ser conduzida de modo a elevar os teores destes nutrientes nas folhas, promovendo aumento da tolerância da cultura aos sais. Este trabalho teve o objetivo de estudar os efeitos de três doses de N e K na tolerância da cultura do tomateiro à salinidade, bem como avaliar a performance de medidores de íons específicos (MIE) na determinação de nutrientes na solução do solo e na seiva da planta. Mudas de tomateiro, híbrido Facundo, foram transplantadas em 23/10/2001 em vasos contendo 60 kg de solo franco-argilo-arenoso, no espaçamento de 1,0 x 0,5 m, em um ambiente protegido com cobertura de polietileno. Os tratamentos foram compostos pela combinação de três níveis de N (7,5; 15,0 e 22,5 g planta-1) e três níveis de K (8, 16 e 24 gK2O planta-1) aplicados via fertirrigação por gotejamento, no esquema fatorial 3x3 com cinco repetições, sendo que à água de irrigação foram adicionados os sais cloreto de sódio e cloreto de cálcio para obtenção de condutividade elétrica da água de 9,5 dS m-1. Foram realizadas coletas da solução do solo e da seiva do pecíolo para determinações dos nutrientes pelos MIE, cujos valores foram comparados com as determinações pelos métodos-padrões. Não foram observados efeitos significativos dos tratamentos sobre o desenvolvimento e a produtividade das plantas, bem como sobre a qualidade dos frutos. As concentrações de nutrientes na solução do solo determinadas com os MIE apresentaram boa correlação com as determinações pelos métodos-padrões, e as concentrações de nutrientes na seiva do pecíolo foram bem correlacionadas aos teores na matéria seca das folhas. A condutividade elétrica e a concentração iônica na solução do solo não puderam ser estimadas a partir dos valores medidos no extrato de saturação ou na solução 1:2 apenas pela correção de umidade, com exceção do K e Na, cujas estimativas foram satisfatórias para baixas concentrações destes elementos na solução do solo. / The concentration of salts in the water is one of the main aspects to be observed to define a strategy of irrigation management, which could take to damages due to the soil salinization, with consequent reduction of crops yield. Once tolerant crops to salinity present larger tenors of some nutrients in the leaves, then the fertilizing in sensitive crops could be conducted in order to increase the tenors of these nutrients in the leaves to increase the crop tolerance to salts. This work had the objective of studying the effects of three doses of N and K in the tomato tolerance to salinity, as well as to evaluate the performance of cardy-ion meters (CIM) in the determination of nutrients in the soil solution and in the sap of the plant. Tomato seedlings, hybrid Facundo, were transplanted in 10/23/2001 in vases containing 60 kg of a sandy-clay-loam soil, spaced 1.0 x 0.5 m, in a greenhouse covered with polyethylene film. The treatments were composed by the combination of three levels of N (7.5; 15.0 and 22.5 g plant-1) and three levels of K (8, 16 and 24 gK2O plant-1) applied by drip fertigation, in the 3x3 factorial scheme with five replications. Salts (sodium chloride and calcium chloride) were added to the irrigation water for obtaining an electric conductivity of 9.5 dS m-1. Soil solution and petiole sap were collected for determinations of the nutrients with the CIM, whose values were compared with the determinations by the standard methods. Significant effects of the treatments were not observed for the development and yield of the plants, as well as for the fruits quality. The concentrations of nutrients in the soil solution determined with CIM showed good correlations with the determinations by the standard methods, and the concentrations of nutrients in the petiole sap were well correlated to the tenors in the dry matter of the leaves. The electric conductivity and the ionic concentration in the soil solution could not be estimated from the measured values in the saturation extract or in the solution 1:2 only by the correction of the water content, except for K and Na, whose estimates were satisfactory for low concentrations of these elements in the soil solution.

Soil salinity, a yield-limiting condition, has plagued crop production for centuries by reducing crop productivity. Research has introduced methods for successfully managing soil salinity. This research discusses the adaptation of established management methods to create new soil salinity management techniques. One adapted technique is an automated crop screening apparatus. A new design was created and successfully used in rapidly screening two strawberry cultivars to determine their tolerance to salinity. Screening crops and determining their tolerance to yield-limiting conditions are essential in managing soil salinity. Another salinity management tool used in this research was electromagnetic induction (EMI). EMI was used to complete a basin-scale inventory over an 18,000 ha study area in Cache County, Utah. The data obtained during the inventory were used to create EMI calibration models and a basin-scale map showing the spatial distribution of apparent soil electrical conductivity (ECa). These new methods for crop tolerance screenings and basin-scale salinity inventories will assist in successfully managing soil salinity and decrease its effect on the global food supply.

This thesis is a comparative study of the life history strategies, and in particular seed germination requirements, in Australian species of the halophyte plant genus Frankenia L. (Frankeniaceae). Frankenia is a cosmopolitan genus that occurs in Mediterranean, semi-arid, and arid regions on distinctive soil types – commonly on saline, sodic or gypseous soils – in habitats such as coastal cliffs, and on the margins of salt lakes, salt-pans and saltmarshes (Summerhayes 1930; Barnsley 1982). The plants are small shrubs or cushion-bushes with pink, white or pale purple flowers, and salt-encrusted recurved leaves. This project investigates germination requirements for Frankenia in relation to seed age, light requirements, temperature preferences, salinity tolerance, and soil characteristics. It also explores two divergent reproductive strategies – notably seed packaging strategies – in relation to environmental variables. Within the 46 currently recognized endemic Australia species, some species have a few ovules per flower and produce only a few larger seeds per fruit, while other species have many ovules per flower and produce many small seeds per fruit. Large-seededness is thought to increase the probability of successful seedling establishment in drought and salt-stressed environments. As both larger- and smaller-seeded species of Frankenia co-occur in close geographical proximity, hypotheses regarding the advantages of large-seededness in stress environments can be tested. By restricting the analysis of seed mass variation to similar habitats and within a single plant genus, it is possible to test ecological correlates that would otherwise be masked by the strong effects of habitat differences and phylogenetic constraints. Overall, larger-seeded Frankenia species were demonstrated to be advantageous for rapid germination after transitory water availability, and for providing resources to seedlings if resources became limiting before their successful establishment. Smaller-seeded species delayed germination until both soil-water availability and cooler temperatures persisted over a longer time period, improving chances of successful establishment for the more slowly growing seedlings that are more reliant on their surroundings for resources. This study produces information on the seed and seedling biology of many Australian species of Frankenia including several that are of conservation significance, e.g. F. crispa with its isolated populations, and the rare and endangered F. plicata. This information is important for the development of conservation management plans for these and other arid zone, halophyte species. In addition, the results of this study are of practical significance in determining the suitability of Frankenia for inclusion in salinity remediation and mine-site rehabilitation projects, and for promoting Frankenia as a drought and salt tolerant garden plant.

This dissertation investigated ingress of postlarval blue crabs Callinectes sapidus to the Newport River estuary, North Carolina, USA. Data from C. similis, Menippe mercenaria, Pachygrapsus transversus, and Arenaeus cribrarius are included in some chapters for comparison. Changes in tolerance to low salinity were examined by: 1) exposing postlarvae (megalopae) collected in coastal and estuarine areas to a range of salinities and 2) determining the cue that stimulates acclimation of coastal megalopae to low salinities, the time to acclimation, and the decrease in salinity necessary for acclimation. Coastal megalopae were less tolerant to salinities of 5 and 10 than megalopae from the estuary. Coastal megalopae became acclimated to low salinities within 12 h when salinity was reduced from 35 to 31. Spatial patterns in abundance during ingress were investigated simultaneously in coastal and estuarine areas. Coastal distributions were determined using nighttime surface plankton tows at slack water after ebb tide and slack water after flood tide on four nights; two each during spring and neap tides. Estuarine distributions were determined using nightly settlement on 'hog's hair' collectors. C. sapidus megalopae were most abundant at the coast east of Beaufort Inlet, but settlement was restricted to western channels of the estuary. Species-specific patterns in abundance were maintained during two spring/neap cycles, possibly due to interactions between larval behavior and physical forcing. Biophysical mechanisms of estuarine ingress were investigated by comparing nightly abundance in coastal and estuarine areas with environmental variables. Comparisons were made using cross-correlation and cross-fourier analyses. High estuarine abundances were associated with wind-driven estuarine inflow and nighttime flood tides. The seasonal pattern of estuarine ingress was strongly associated with the seasonal pattern of alongshore wind stress, suggesting that inter-annual variations in atmospheric forcing may determine the yearly abundance of megalopae arriving in estuarine nursery habitats. The effect of sampling interval on annual megalopal abundance estimates was determined using an 11-year dataset of nightly settlement. Variability in abundance estimates increased with increasing sampling interval. Switching from a one day to two day sampling interval resulted in a 20 % decrease in the likelihood of detecting a significant correlation between annual abundance and CPUE in the North Carolina blue crab pot fishery. / Dissertation

The aim of this study was to investigate the reproductive ecology including fecundity, reproductive season, timing of larval release, evaporative water loss during reproductive migration, and the salinity tolerance of first zoeal stage of Cardisoma carnifex in Houwan, Hengchun Peninsula. The average carapace width of ovigerous females was 70.5 ¡Ó 6.57 mm, with a size range of 56.0-93.7 mm. Fecundity intimates increased with size and the number of hatched larvae from individual female varied from 90,000 to 490,000. The reproductive season of C. carnifex began at the onset of the rainy season and ends approximately at the end of that season. The reproductive season was from June to Oct. in 2009 and May to Sept. in 2010. The peaks of larval release occurred in July in 2009, 2010. Some females had the capacity in spawning twice during a reproductive season. Ovigerous females releasing larvae synchronously. The relationship between larval release timing and environmental cycle is listed in decreasing order of importance: diel rhythm, semilunar rhythm, tidal amplitude rhythm, and a low correlation was found with the tidal rhythm. Ovigerous females of C. carnifex started to release larvae after the new and full moon, lasting for 6-8 days with peaks occurring 4-6 days after the new and full moon. The peaks of larval release occurred within 2-3 hours after the sunset time (i.e., between 1930H and 2130H). This species exhibits different larval release timing and behavior compare to other species of Gecarcinidae; ovigerous females of gecarcinid crabs follow a lunar rhythm but C. carnifex follow a semilunar rhythm. More than half of the ovigerous females stayed in the water for up to 10 min (average 5.5 ¡Ó 2.87 min) and could move to deep water (i.e., 120 cm) to release their larvae. A few females even released their larvae in the freshwater environment. For C. carnifex, a mean of 15¢H of its original weight was lost by the time they died and the osmolality of the hemolymph is 856 mOsm kg-1. Compare with the hemolymph osmolality of ovigerous females (694 ¡Ó 6.3 mOsm kg-1), the results indicated that the ovigerous females at Houwan may not experience severe water loss during larval release migration. The first zoeal stage of C. carnifex could not survive in the freshwater, all larvae died within 2 hours. However, at salinities large than 5‰, most larvae could survive for more than 3 days. The results show first zoeal stage of C. carnifex had adapted to the low salinity in the estuary.

Concentrate (when discharged to the ocean) may have chronic/acute impacts on marine ecosystems, particularly in the mixing zone around outfalls. The environmental impact of the desalination plant discharges is very site- and volumetric specific, and depends to a great extent on the salinity tolerance of the specific marine microbial communities as well as higher order organisms inhabiting the water column in and around this extreme discharge environment. Scientific studies that aim to grant insight into possible impacts of concentrate discharge are very important, in order to understand how this may affect different marine species when exposed to elevated salinity levels or residual chemicals from the treatment process in the discharge site. The objective of this PhD research was to investigate the potential environmental effects of the concentrate discharge in the near-field area around the submerged discharge of the King Abdullah University of Science and Technology (KAUST) seawater reverse osmosis (SWRO) plant by a combination of biological and hydrological studies. Possible changes in microbial abundance were assessed by using flow cytometric (FCM) analysis on a single-cell level in 107 samples, taken from the discharge area, the feed-water intake area and two control sites. Results indicate that changes in microbial abundance in the near-field area of the KAUST SWRO outfall are minor and appear to bethe result of a dilution effect rather than a direct impact of the concentrate discharge. In order to also investigate potential impacts on higher order organisms, a longterm in-situ salinity tolerance test at the discharge site was conducted on the coral Fungia granulosa and its photophysiology. The corals were exposed to elevated levels of salinity as a direct result of concentrate discharge. Their photosynthetic response after exposure to extreme salinity conditions around the full-scale operating SWRO desalination discharge was measured. A pulse amplitude modulated (PAM) fluorometer was used to assess photochemical energy conversion in photosystem II (PSII) measured under constant concentrate discharge conditions. Based on a literature review, we anticipated distinct impairment of photosynthetic characteristics as a response to elevated salinity levels. We also expected particularly quick indications of bleaching for the specimens exposed to the highest salinity levels. The hypothesis was strongly rejected as symbiotic dinoflagellates of Fungia granulosa demonstrated high tolerance to hyper saline stress as measured by effective quantum yield of PSII (ΔF/Fm’) during this study. A series of propulsion driven autonomous underwater vehicle (AUV) missions with velocity and salinity measurements were used for possible plume detection and evaluation of the discharge. The Cornell Mixing Zone Expert System (CORMIX) was additionally utilized in order to assess discharge performance under different ambient velocity magnitudes. Results show that AUV missions could provide significant insight with regards to plume identification and effluent discharge environmental impact studies. Combined with robust in-situ field measurements, models and expert systems were used to evaluate possible impacts on the marine environment in comparison with regulatory mixing zones and dilution criteria. Based on the findings and existing environmental governance (national and international), a revised regulatory framework for mixing zones within the Kingdom of Saudi Arabia is recommended.

No description available.

A concentração de sais na água é um dos principais aspectos a ser observado para se definir uma estratégia de manejo da irrigação, podendo levar a prejuízos pela salinização do solo, com conseqüente redução do rendimento das culturas. Visto que culturas tolerantes à salinidade apresentam maiores teores foliares de certos nutrientes, então a adubação em culturas sensíveis poderia ser conduzida de modo a elevar os teores destes nutrientes nas folhas, promovendo aumento da tolerância da cultura aos sais. Este trabalho teve o objetivo de estudar os efeitos de três doses de N e K na tolerância da cultura do tomateiro à salinidade, bem como avaliar a performance de medidores de íons específicos (MIE) na determinação de nutrientes na solução do solo e na seiva da planta. Mudas de tomateiro, híbrido Facundo, foram transplantadas em 23/10/2001 em vasos contendo 60 kg de solo franco-argilo-arenoso, no espaçamento de 1,0 x 0,5 m, em um ambiente protegido com cobertura de polietileno. Os tratamentos foram compostos pela combinação de três níveis de N (7,5; 15,0 e 22,5 g planta-1) e três níveis de K (8, 16 e 24 gK2O planta-1) aplicados via fertirrigação por gotejamento, no esquema fatorial 3x3 com cinco repetições, sendo que à água de irrigação foram adicionados os sais cloreto de sódio e cloreto de cálcio para obtenção de condutividade elétrica da água de 9,5 dS m-1. Foram realizadas coletas da solução do solo e da seiva do pecíolo para determinações dos nutrientes pelos MIE, cujos valores foram comparados com as determinações pelos métodos-padrões. Não foram observados efeitos significativos dos tratamentos sobre o desenvolvimento e a produtividade das plantas, bem como sobre a qualidade dos frutos. As concentrações de nutrientes na solução do solo determinadas com os MIE apresentaram boa correlação com as determinações pelos métodos-padrões, e as concentrações de nutrientes na seiva do pecíolo foram bem correlacionadas aos teores na matéria seca das folhas. A condutividade elétrica e a concentração iônica na solução do solo não puderam ser estimadas a partir dos valores medidos no extrato de saturação ou na solução 1:2 apenas pela correção de umidade, com exceção do K e Na, cujas estimativas foram satisfatórias para baixas concentrações destes elementos na solução do solo. / The concentration of salts in the water is one of the main aspects to be observed to define a strategy of irrigation management, which could take to damages due to the soil salinization, with consequent reduction of crops yield. Once tolerant crops to salinity present larger tenors of some nutrients in the leaves, then the fertilizing in sensitive crops could be conducted in order to increase the tenors of these nutrients in the leaves to increase the crop tolerance to salts. This work had the objective of studying the effects of three doses of N and K in the tomato tolerance to salinity, as well as to evaluate the performance of cardy-ion meters (CIM) in the determination of nutrients in the soil solution and in the sap of the plant. Tomato seedlings, hybrid Facundo, were transplanted in 10/23/2001 in vases containing 60 kg of a sandy-clay-loam soil, spaced 1.0 x 0.5 m, in a greenhouse covered with polyethylene film. The treatments were composed by the combination of three levels of N (7.5; 15.0 and 22.5 g plant-1) and three levels of K (8, 16 and 24 gK2O plant-1) applied by drip fertigation, in the 3x3 factorial scheme with five replications. Salts (sodium chloride and calcium chloride) were added to the irrigation water for obtaining an electric conductivity of 9.5 dS m-1. Soil solution and petiole sap were collected for determinations of the nutrients with the CIM, whose values were compared with the determinations by the standard methods. Significant effects of the treatments were not observed for the development and yield of the plants, as well as for the fruits quality. The concentrations of nutrients in the soil solution determined with CIM showed good correlations with the determinations by the standard methods, and the concentrations of nutrients in the petiole sap were well correlated to the tenors in the dry matter of the leaves. The electric conductivity and the ionic concentration in the soil solution could not be estimated from the measured values in the saturation extract or in the solution 1:2 only by the correction of the water content, except for K and Na, whose estimates were satisfactory for low concentrations of these elements in the soil solution.

Increasing salinity is a worldwide problem, but the knowledge on how salt enters the roots of plants remains largely unknown. Non-selective cation channels (NSCCs) have been suggested to be the major pathway for the entry of sodium ions (Na+) in several species. The hypothesis tested in this research is that PQ loop (PQL) proteins could form NSCCs, mediate some of the Na+ influx into the root and contribute to ion accumulation and the inhibition of growth in saline conditions. This is based on previous preliminary evidence indicating similarities in the properties of NSCC currents and currents mediated by PQL proteins, such as the inhibition of an inward cation current mediated by PQL proteins by high external calcium and pH acidification. PQL family members belonging to clade one in Arabidopsis and barley were characterized using a reverse genetics approach, electrophysiology and high-throughput phenotyping. Expression of AtPQL1a and HvPQL1 in HEK293 cells increased Na+ and K+ inward currents in whole cell membranes. However, when GFP-tagged PQL proteins were transiently overexpressed in tobacco leaf cells, the proteins appeared to localize to intracellular membrane structures. Based on q-RT-PCR, the levels of mRNA of AtPQL1a, AtPQL1b and AtPQL1c is higher in salt stressed plants compared to control plants in the shoot tissue, while the mRNA levels in the root tissue did not change in response to stress. Salt stress responses of lines with altered expression of AtPQL1a, AtPQL1b and AtPQL1c were examined using RGB and chlorophyll fluorescence imaging of plants growing in soil in a controlled environment chamber. Decreases in the levels of expression of AtPQL1a, AtPQL1b and AtPQL1c resulted in larger rosettes, when measured seven days after salt stress imposition. Interestingly, overexpression of AtPQL1a also resulted in plants having larger rosettes in salt stress conditions. Differences between the mutants and the wild-type plants were not observed at earlier stages, suggesting that PQLs might be involved in long-term responses to salt stress. These results contribute towards a better understanding of the role of PQLs in salinity tolerance and provide new targets for crop improvement.