The research outlined in this dissertation represents a study towards the examination of the presence of mitochondrial arginine kinase (AK) activity in horseshoe crab (Limulus polyphemus) hearts and its possible physiological significance. The existence of such a mitochondrial bound AK was hinted at by the residual enzymatic activity in the mitochondrial pellet and the ability of arginine to stimulate state 3 respiration in the presence of ATP. The presence of a mitochondrial bound AK (AKm) in L. polyphemus hearts was confirmed by sucrose-density centrifugation and solubilization experiments. Between 1.5 and 2% of total cytoplasmic AK activity appeared to be associated with the mitochondria. Cellulose acetate electrophoresis revealed the existence of two populations of AKm--a 'fast' electrophoretic form (AKmf), migrating identically to cytoplasmic AK (AKc), and a 'slow' electrophoretic form (AKms). Both forms were present in a 1:1 ratio. The 'fast' form was easily extractable while AKms showed hydrophobic characteristics, only extractable with detergents. SDS-PAGE electrophoresis of these isoenzymes following purification showed the molecular weight subunit of both AKc and AKmf to be virtually the same (39-40 kD), but that of AKms being slightly higher (43.5 kD). The peptide maps of AKc and AKmf were identical, whereas that of AKms displayed some unique peptide fragments. AKmf is therefore thought to be a similar protein as AKc while AKmf may contain, however, an additional hydrophobic sequence for insertion and anchoring into the inner membrane of the mitochondrion. / Kinetic and thermodynamic experiments in the presence and absence of oxidative phosphorylation (OP) showed no difference in the kinetic parameters or movement of the mass action ratio, respectively. These results thus do not suggest effective functional coupling between OP (e.g. the adenosine nucleotide translocator) and the AKm reaction. These experiments exclude the possibility that there is preferential access of the AKm enzyme(s) for the product of respiration (ATP). A study comparing the efficacy of bound mitochondrial AK versus a soluble source of ADP showed that mitochondrial associated AK might be advantageous by minimizing the diffusion of ADP. / Source: Dissertation Abstracts International, Volume: 51-03, Section: B, page: 1077. / Major Professor: William Ross Ellington. / Thesis (Ph.D.)--The Florida State University, 1990.

Sea urchin U1 genes coding for the major embryonic U1 RNA are in the tandemly repeated units. The U1 repeat unit in L. variegatus is variable in size from 1.2 to 1.4 Kb while that in S. purpuratus has a homogenous size of 1.1 Kb. Two types of U1 repeats have been isolated from L. variegatus. They are conserved in the 5$\sp\prime$ flanking region for 500 bp, but vary in the 3$\sp\prime$ flanking sequence immediately after the CAAAGAAAGAAAA sequence necessary for 3$\sp\prime$ end formation. The tandemly repeated U1 cluster of S. purpuratus ends just 3$\sp\prime$ to the U1 coding region. / The sea urchin U1 gene is transcribed by RNA polymerase II in isolated nuclei, but it can be transcribed by RNA polymerase III in sea urchin nuclear extracts. Two assays were used for testing promoter function, a microinjection assay for testing the expression of U1 genes in vivo and a DNA-dependent nuclear extract for testing expression in vitro. At least 200 nucleotides, but no more than 345 nucleotides, 5$\sp\prime$ to the gene are required for the expression of U1 gene in vivo. Two of the four highly conserved regions between L. variegatus and S. purpuratus U1 5$\sp\prime$ flanking region are in these 142 nucleotides. In contrast, none of the 5$\sp\prime$ flanking region, but rather an internal promoter region is required for the synthesis of U1 RNA by RNA polymerase III in vitro. The internal promoter region contains a tRNA A-box consensus sequence and an 11-bp region with identical sequence to one of the highly conserved regions. These data suggest that the four highly conserved regions in the 5$\sp\prime$ flanking sequence are important for the expression of the sea urchin U1 gene. / Source: Dissertation Abstracts International, Volume: 50-12, Section: B, page: 5480. / Major Professor: William F. Marzluff, Jr. / Thesis (Ph.D.)--The Florida State University, 1989.

Although many researchers have examined the phenomenon of intertidal zonation and its structuring processes in rocky habitats, similar studies concerning soft-bottom habitats are relatively uncommon. The bivalve assemblage of Polymesoda caroliniana (Corbiculidae) and Rangia cuneata (Mactridae), common in the shallow subtidal and intertidal zones of the mesohaline-oligohaline regions of southeastern United States estuaries, allows some analogies to previously studied rocky intertidal communities in that the adults of these bivalves are large (20-70 mm in shell length), and move very little, making the populations relatively easy to census and manipulate. I conducted field surveys and manipulative experiments on populations of R. cuneata and P. caroliniana between 1982 and 1984 in the Ochlockonee-Sopchoppy estuary of northwestern Florida. The emphasis of the research was description of the vertical distribution of members of each species, and analysis of factors controlling these distributions, including recruitment, physiological factors, disturbance, and potential competitive effects. Results indicate that R. cuneata is a subtidal inhabitant whose upper bound is controlled by physical factors, including physiological tolerances to such factors, and probably a lack of sufficient time for feeding and respiration. Recruitment of R. cuneata is highly variable, and results in populations dominated by single age classes. P. caroliniana is shown to be an intertidal inhabitant. The lower bound of the P. caroliniana population is determined, in an ecological sense, by larval settlement, but in an evolutionary time frame is probably controlled by biological factors such as predation and disturbance by predators and bioturbators. P. caroliniana seems to recruit regularly, but juvenile mortality is high, so recruitment to the adult population is low. No competitive effects between adult P. caroliniana and R. cuneata were found. / Source: Dissertation Abstracts International, Volume: 49-03, Section: B, page: 0601. / Major Professor: William Heard. / Thesis (Ph.D.)--The Florida State University, 1987.

The fauna and flora living on the bay scallop, Argopecten irradians, was examined from twenty-five consecutive monthly collections. The nematode fauna of scallops differed from that of nearby sediments and seagrasses in that it was less diverse and was dominated by three species, Viscosia macramphida, Syringolaimus striatocaudatus, and Chromadora nudicapitata. These species were rare in sediment samples and common, though not as abundant, on seagrasses. They accounted for 79.3% of the total individuals on scallops. The simplicity of this nematode assemblage was exploited in field and laboratory experiments designed to uncover the ecological factors responsible for the temporal variation of the dominant species. / Initial field experiments justified the view of scallop shells as isolated communities because the swimming activities of scallops did not remove the shell's nematode fauna, and space experimentally made available on a scallop shell was not appreciably recolonized over a four-hour period. Consequently, the system could be studied experimentally. / The major finding of the research was discovering that each species responded to a different ecological factor. Viscosia was most abundant on scallop shells in late summer. Its abundance coincided with a peak in diatom abundance, its preferred food. Chromadora was abundant in the spring on young scallops that had recently detached from blades of the seagrass Thalassia testudinum. At that time, Chromadora was the most abundant nematode on the blades, so its abundance on newly steeled scallops was a reflection of the recent history of the shell. It remained abundant on scallops until the early summer. A long-term field recolonization experiment determined that immigration of Chromadora from seagrasses was not responsible for the continued success of the shell populations. Syringolaimus increased in abundance over the course of the study, and was the overall dominant on scallop shells once Chromadora populations declined. A laboratory culture experiment determined that Syringolaimus was not able to competitively exclude Chromadora under conditions approximating those in the field. Rather, the species coexisted in densities consistent with their field values. / Source: Dissertation Abstracts International, Volume: 47-02, Section: B, page: 0465. / Thesis (Ph.D.)--The Florida State University, 1985.

It is the primary purpose of this study to develop a theoretical framework that can be used to analyze Florida's resident recreational anglers' behavior toward fishing days per trip. This is accomplished by focusing on linkages between household budgeting and recreational fishermen's behavior. The flexibility is also introduced in the theoretical model to accommodate the influence of household income on the demand for fishing days per trip through the concept of allocated household income for fishing. In addition, extended within this theoretical framework is the Pearce-Gibbs travel cost model by introducing a non-linear budget constraint. / Empirical results indicate that household income does not explain Florida resident anglers' demand for fishing days per trip. This conclusion is based on the fact that the results of the household income variable are statistically insignificant. However, there is some evidence that allocated income (i.e., money currently available) is a more appropriate variable for explaining the demand for fishing days per trip. / The second and third objectives of the study were to estimate Hicksian and Marshallian user value for a day's fishing and the value of Florida's resident saltwater recreational fishery, respectively. It is found that the Hicksian compensating and equivalent variations did not diverge much in magnitude from the Marshallian consumer surplus. This is due to the fact that the income effect is generally very small. The annual 1980 value of the resident saltwater fishery ranges from $299.27 million to \$6.075 billion. The value of $1.6 billion obtained by Bell, {\it et al.} (1982) falls in the range of our estimates. / Lastly, empirical results are consistent with the current move toward a resident saltwater fishing license in the state of Florida. Selling an artificial property right, i.e., a saltwater fishing license, for common property fishery resources is an essential pre-condition in establishing more effective management policy to protect marine fishery resources. This policy prevents free-riders from exploiting marine fishery resources and reduces Hardin's "The Tragedy of the Commons." / Source: Dissertation Abstracts International, Volume: 48-10, Section: A, page: 2684. / Thesis (Ph.D.)--The Florida State University, 1987.

As we have come to depend on aquaculture to supplement natural fisheries, intensive culture methods have increased production. Accompanying environmental damage--non-point source pollution, loss of biodiversity and struggle for water--has offset food and financial gains. Problems surrounding food production are amplified in arid lands, as the potential of irrigated agriculture is weighed against the value of water. Through the following research, I studied integration of aquaculture and agriculture through multiple uses of water and nutrients, to reduce environmental impacts. When managed properly, integration can provide multiple cash crops, increased food and fiber production with reduced inputs. Integration allows for groundwater and nutrients in water and solid waste to be reused. Shrimp farms in Arizona use low-salinity ground water from aquifers for shrimp ponds and agricultural irrigation. On one of these farms, effluent is reused for irrigation of olive trees and other field crops. In Chapter 3, I described an experiment designed to quantify changes in the height of olive trees due to irrigation with shrimp effluent. Trees receiving effluent grew an average of 61.0 cm over the two-year experiment, 70.4 cm with fertilizer and 48.4 cm in the well water treatment. No negative effects due to effluent irrigation were found, while increases in water use efficiency were realized by producing two crops with the same irrigation water. Multiple uses of water are also possible in smaller scale agriculture systems. I performed a financial analysis of a small-scale aquaponics system, integrated hydroponics and aquaculture, in Chapter 4. Biological viability of such systems is clear. By building and managing this system for five months, I examined economic viability, by analyzing annual costs and revenue. Calculating net present value showed that the system was not financially viable unless labor costs were excluded. Financial returns were between 3,794 and 10,640 over six years. In five months, this system produced 181.4 kg of food, with fish feed, iron and water as the only inputs. This study showed potential for using small-scale aquaponics as a hobby, in schools, and as a tool for agricultural economics education, but not as a business opportunity.

The virile crayfish (Orconectes virilis), an aggressive polytrophic species, has been introduced into many Arizona streams. I investigated competition and predation between this crayfish and several native Arizona fishes. I conducted field experiments to assess competition for food between crayfish and fish, and laboratory experiments to examine competition for shelter and food, and predation. In Sabino Creek, I manipulated crayfish densities in isolated pools to examine effects of crayfish on growth, mortality, and recruitment of Gila chub (Gila intermedia). Regardless of crayfish density, Gila chub declined slightly in weight and condition. Mortality and recruitment did not differ between densities of crayfish. I examined crayfish effects on benthic macroinvertebrates, a submerged aquatic macrophyte and associated invertebrates, and three fish species in a small stream in the White Mountains by fencing eight stream sections to prevent movement. The three fishes were speckled dace (Rhinichthys osculus), Sonora sucker (Catostomus insignis), and desert sucker (C. clarki). Molluscs > 10 mm and macrophytes were less abundant at sites with a high density of crayfish than at sites with low crayfish densities. Insect diversity was lower in high- vs. low-density sites. No treatment effect was observed on growth or condition of individually marked fish. Short-term laboratory experiments demonstrated predatory interactions and competition for shelter between crayfish and Gila chub, desert sucker, and speckled dace. Crayfish used shelter more than fish, displaced fish from shelter, and frequently attacked fish. Fish never attacked crayfish, and only once displaced crayfish from shelter. In predation experiments, crayfish preyed upon all species, but preyed most heavily upon desert suckers. Fish never altered use of the water column in the presence of crayfish. Density manipulation experiments in a laboratory measured food competition between crayfish and two native fishes. Growth of Gila chub was less affected by crayfish than by increased density of Gila chub. Thus crayfish are not strong competitors with Gila chub for food. However, growth of flannelmouth sucker (Catostomus latipinnis) was negatively impacted by presence of crayfish. These laboratory experiments provide evidence that introduced crayfish can reduce fish growth by competition for food, and that native fishes are vulnerable to crayfish predation.

Selenium bioaccumulates along the lower Colorado River and may impact fish and waterfowl. Selenium may be reduced in lakes or reservoirs by flushing (increasing the water exchange rate). Therefore, I monitored selenium levels in water, sediment, and bluegill (Lepomis macrochirus) in response to flushing on the Cibola NWR in the lower Colorado River Valley, California and Arizona. Selenium in the lakewater was below the detection level of 5.6 ppb wet weight (WW) but data from the US Geological Survey (1990-1995) showed that selenium levels in the water ranged from 1 to 3 ppb WW in the mainstem Colorado River 135 km upstream from Cibola Lake. There was no predictable trend in selenium in the sediment after flushing. It was the same after the first flushing, lower after the second flushing, and higher after the third flushing. Selenium levels in the biota also did not vary in a predictable way after flushing. It went up after the first flushing, down after the second flushing, and up after the third flushing. One might speculate that higher flushing rates, or continuous flushing might result in lower selenium levels in biota and sediment. However, selenium levels in the sediment (1.10 ppm DW) and bluegill (4.93 ppm DW) in Cibola Lake were not significantly different than levels in the sediment (0.86 ppm DW) and bluegill (4.83 ppm DW) in a comparable backwater lake (Mittry Lake, Arizona) that was continuously flushed. Therefore, flushing does not appear to be a viable strategy for managing selenium levels in backwater lakes along the lower Colorado River.

The primary objective of this study was to evaluate the economic feasibility of introducing fish culture into irrigated cotton production on farms in central Arizona. The representative farm adopted in this study is a cotton farm described in Arizona Field Crop Budgets, 1994-95. The only adjustment necessary for the farmer to make is to keep water in the ditches at all times. Water as a production variable for fish production was thus calculated only for the additional quantity required. Analysis of these production systems was accomplished by budgeting procedures as well as statistical analysis. The economic-engineering (synthetic firm technique) was employed to develop the input-output coefficients necessary for analysis. Five fish densities and eight ditch capacities were tested. The production function was estimated using input and yield data. Three functional forms (linear, quadratic and Cobb-Douglas) were examined to determine how well they estimated the production system. Using budget analysis, a fish stocking density of six fish per cubic meter and a ditch capacity of 2,925 m3 appear to provide the optimal production scenario, if the percentage of fish reaching harvestable size is improved from 66 percent to at least 80 percent. This density has been proven to require minimum production costs and to provide the most efficient use of resources. However, production functions estimated in this study indicate that profits can be increased through additional use of feed. At any ditch capacity, a density of six fish per cubic meter, provides the optimal economic results, MVP = PX2 Finally, the implication of the findings of this study are that raising tilapia in irrigation ditch systems on cotton farms in central Arizona is feasible at a stocking density of six fish per cubic meter. Studies to improve the percentage of fish reaching marketable size at this density is very critical. Increasing the initial size of the fingerlings could be a consideration in improving the percentage of fish reaching marketable size and eventually increasing optimum economic returns.

Integration of aquaculture with agriculture appears to be an excellent way to save water, dispose of aquaculture effluents, and provide additional fertilizer to the agricultural crop. However, the amount of nitrogen transferred from fish effluent to plants has not been quantified. Therefore, I tested the feasibility of using ¹⁵N labeled fish feed, to produce a labeled effluent that could be used to study the fate of nitrogen in an integrated aquaculture and agriculture system. A pilot project showed that tilapia accepted labeled feed, that ¹⁵N ammonium sulfate was not hazardous to fish, and that labeled effluent could be detected in lettuce. Two experiments irrigating lettuce with the labeled effluent showed the pathways of nitrogen movement. Different combinations of chemical fertilizer and tap water and fish effluent were used to irrigate lettuce. Nitrogen transfer was quantified based on the percentage of ¹⁵N recovered from the fish effluent by plants. Lettuce that received fish effluent as the only source of nitrogen recovered practically all the available inorganic nitrogen. However, there was not sufficient nitrogen for optimal plant growth. Plants that received a combination of fish effluent and chemical fertilizer were more efficient at uptaking the nitrogen in the chemical fertilizer than in the fish effluent. Available inorganic nitrogen levels in fish effluent were generally too low to meet the nitrogen needs of plants. However, decomposition of organic material over time may improve long term soil fertility. Concentration of fish culture effluent might also increase nutrient content. The nitrogen budget for fish tanks used to produce effluent for these studies showed that fish contained the highest amount of nitrogen, followed by algae and effluent in descending order. Estimates of nitrogen assimilation based on ¹⁵N recovery from labeled fish feed did not agree with calculations based on recovery of total nitrogen. Therefore ¹⁵N recovery does not appear to be a good indicator of nitrogen assimilation by fish in short term experiments.