Thesis (doctoral)--University of Lund, 1983. / Spine title: Transport routes of PCBs in aquatic ecosystems. Sponsoring organization: National Swedish Environmental Protection Board. Includes bibliographical references.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1985. / Vita. Abstract. Includes bibliographical references (leaves 118-127). Also available via the Internet.

Metabolites of DDT were detected in five out of six major organs of blue crabs, Callinectes sapidus, taken from estuarine populations. Residue concentrations were highest in the hepatopancreas and below the limit of detection in the heart. Concentrations in pooled gonad samples (ovaries + testes) depended on the stage of development of the ovaries. Residue levels were low in claw and backfin muscles. Adult blue crabs were exposed for 12 hours to 0.01, 0.1, and 1.0 ppm DDT in water. No significant mortality was recorded. DDT was absorbed through the gills and transported to the hepatopancreas via the hemolymph. Biotransformation and distribution of DDT and its metabolites was regulated by the hepatopancreas. Induction of metabolic transformation of DDT to DDD and DDE occurred immediately. Storage of residues was greatest in the hepatopancreas and developing ovaries . Rates of loss of DDT residues from organs was subject to considerable variation. This dissertation is from the Joint Program Degree from the College of William & Mary and University of Virginia and awarded by the University of Virginia.

Zooplankton composition, distribution, biomass and biochemical constituents were determined monthly in the lower Chesapeake Bay for two years beginning in August 1971. Settled volume, dry weight, and ash-free dry weight estimates of total biomass were generally consistent in showing summer and late winter peaks. A mean dry weight peak of 258 mg/m3 in August 1971 decreased precipitously to a December low of 9 mg/m3, then increased to a March 1972 peak of 199 mg/m3. The second year mirrored this pattern, except that the passage of Tropical Storm Agnes in June 1972 lowered the summer peak values for July and August considerably. In August 1971 and again in August 1972, a total of 53 species, from four dominant major groups, were used to characterize four distinct geographical cluster zones. The summer zooplankton was dominated by cladocerans, largely Penilia avirostris and Evadne tergestina, and the copepod Acartia tonsa. Decapod larvae proved to be the most diverse summer group studied, containing 30 species in August 1971 and 33 species in August of 1972. Dominant species included Upogebia affinis, Callinectes sapidus, and Uca sp. Chaetognath peaks in September of each year consisted almost entirely of Sagitta tenuis. Winter populations contained less than half the number of taxa as summer zooplankton and were dominated by Acartia clausi. This species almost completely replaced Acartia tonsa by April of each year. The most notable effects of the lowered salinities caused by Tropical Storm Agnes in the summer of 1972 were a drastic reduction in cladoceran abundance and a compression of chaetognath distribution to the higher salinity areas near the bay mouth. Protein, the largest organic fraction of the zooplankton, usually accounted for 40-60% of the total dry weight. Mean monthly lipid values ranged from 1.9 to 9.5% of the dry weight, and carbohydrate appeared only as a minor organic fraction. This dissertation is from the Joint Program Degree from the College of William & Mary and University of Virginia and awarded by the University of Virginia.

Laboratory and environmental studies of striped bass (Morone saxatilis) X white perch (M. americana) and striped bass X white bass (M. chrysops) were used to-determine the feasibility of introducing these hybrids into an estuary as a supplement to natural populations of the parental species. Growth patterns, survival, and general hardiness of the hybrids were used as criteria. Growth of striped bass X white perch hybrids in the laboratory was apparently somewhat less than growth of natural populations of striped bass, but was much greater than growth of natural populations of white perch. Hybrid growth was slower than striped bass growth under the same conditions, but hybrid survival was much better than striped bass survival. The hybrids were able to survive and grow in estuarine salinities. Most hybrids matured at two years of age. Striped bass X white bass hybrids were able to adapt to an estuarine environment (the Rappahannock River, Virginia) and could successfully compete with striped bass and other resident ichthyofauna. Hybrid growth was faster than striped bass growth in the Rappahannock and was considerably faster than growth of various freshwater populations of white bass. Hybrids were caught in salinities as high as 17%. They were mature at two years of age. Both hybrids were described using meristic and morphometric characteristics. They were both found to be generally intermediate to the parental species, but in certain traits they tended to resemble one parent more closely than the other. Striped bass, white perch, and their hybrid all had a diploid chromosome number of 48. Possible karyological differences are discussed. One or both hybrids may be suitable for introduction into an estuary to supplement natural populations of striped bass and white perch, but more comprehensive environmental experiments are needed. This dissertation is from the Joint Program Degree from the College of William & Mary and University of Virginia and awarded by the University of Virginia.

Amazonian freshwaters host the most diverse ichthyofauna in the world but the ecological mechanisms that generate and regulate this diversity are poorly known. I performed the first comparison of spatial and temporal patterns of fish community diversity among the four primary aquatic habitats of the Amazon (major rivers, floodplains, lowland terra firme streams, and upland shield streams) and among the three distinct chemical water types in Amazon river-floodplain systems (low-nutrient blackwaters and clearwaters, and high-nutrient whitewaters). To minimize confounding influences of geographical variation in species ranges, my study targeted one of the few parts of Amazonia (near Santarém, Brazil) where all four habitats and all three river-floodplain water types occur in close proximity. In the first of three chapters, I compare diversity and biomass between blackwater, clearwater, and whitewater rivers and floodplains. My results provide the first support for positive species-energy and biomass-energy relationships across multiple aquatic habitat types from the same biome and region. In Chapter 2 I compare patterns of temporal beta-diversity, and beta-deviations from null model simulations, to demonstrate that species turnover is positively correlated to seasonality and hydrological connectivity among the four Amazonian habitats types but is uninfluenced by water type. In Chapter 3 I compare up-river transects from the common confluence of a blackwater, Clearwater, and whitewater river to infer that abrupt gradient of water chemistry act as major barriers to fish dispersal. My results have important implications for biodiversity monitoring and conservation planning in the increasingly threatened aquatic habitats of the Amazon basin.

Despite an increased global interest in harmful algal bloom (HAB) species and eutrophication, the relationship between nutrient sources and changes in species composition or toxicity remains unclear. Stable isotopes are routinely used to identify and track nitrogen (N) sources to water bodies, as sources can be differentiated based on stable isotope values. While literature is available describing N fractionation by diatoms and coccolithophores, data are greatly lacking regarding isotope fractionation by dinoflagellates. Here we investigate the fractionation of nitrogen isotopes by saxitoxin-producing Alexandrium fundyense, to validate the use of the δ15N of particulate organic matter and identify the nitrogen source fueling a dinoflagellate bloom and its toxicity. The effects of N chemical form on isotope fractionation, toxin content, and toxicity, were investigated using isolates in single-N and mixed-N experiments. Growth on NO3-, NH4+, or urea, resulted in isotope fractionation of 2.761.48‰, 29.019.32‰, or 0.340.19‰, respectively, with the lowest cellular toxicity and toxin quotas reported during urea utilization. Toxin composition and growth rates, however, remained constant across all N treatments, showing no effects of NO3-, NH4+, or urea utilization. Alexandrium fundyense was then preconditioned to either NO3-, NH4+, or urea, and abruptly inoculated into mixed-N medium containing all three chemical forms. All treatments initially utilized NH4+ and urea upon inoculation into mixed medium, suggesting no effect of preconditioning. Cells only began utilizing NO3- after NH4+ decreased below 2-4 M in the medium. During the inhibition of NO3- uptake by NH4+ utilization, the cellular δ15N was at its lowest (-5‰), and through the course of the experiment, the δ15N continuously changed to mimic the isotope value of the most recent N source(s) being utilized. When utilizing multiple sources, the isotope signature of the cells fell between the signal of the two N sources. Together this suggests that in NO3- and urea rich environments, the 15NPOM would reliably look like the source or sources of nitrogen utilized, but that caution should be taken in NH4+ rich environments where the large value could lead to misinterpretation of the signal. Nutrients are only one factor influencing bloom dynamics, but information about the relative importance of natural or anthropogenic nutrients in the development and toxicity of bloom events is necessary to predict future shifts in phytoplankton species composition, density, and toxicity.

The work of this dissertation examined the secondary metabolites of several blooms of the marine cyanobacterium Lyngbya collected in Guam and Florida with an emphasis on the isolation and structure elucidation of novel biologically active compounds. The introduction in Chapter One provides a brief history of marine natural products, a description of cyanobacteria and a summary of peptides isolated from Lyngbya collected in the Caribbean. In Chapter Two, a bioassay-guided fractionation of a Floridian collection of Lyngbya polychroa led to the isolation and structural determination of the cytotoxin desacetylmicrocolin B and the known compounds microcolins A and B. The structures were established by nuclear magnetic resonance (NMR) spectroscopic analysis. All three compounds inhibited the growth of cancer cell lines HT-29 and IMR-32 at nanomolar concentrations. Microcolins A and B were found to have little activity in the ecological assay against the marine fungus Dendryphiella salina. Chapter Three describes the isolation and structure elucidation of the glycosidic, acyl proline derivative tumonoic acid J from a sample Lyngbya sp. collected in Guam. The planar structure was determined by 1D and 2D NMR spectroscopy in conjunction with high resolution-mass spectrometry (HR-MS) data. Tumonoic acid J showed moderate activity in the ecological assay against the marine fungus D. salina. In Chapter Four, NMR-guided fractionation of a Floridian sample of Lyngbya majuscula led to the isolation of two novel cyclic peptides porpoisamides A and B. The planar structures were determined by 1D and 2D NMR spectroscopy with HR-MS data. The absolute configurations of these two compounds were defined through chiral chromatographic methods and derivatization techniques. / The porpoisamides showed only moderate activity in cytotoxicity assays against cancer cell lines HCT-116 and U2OS. Finally, Chapter Five examines a potential ecological role of compounds isolated from marine cyanobacte ria. These secondary metabolites may function as chemical defenses against competing microorganisms within marine environments. Compounds isolated from cyanobacteria were tested for anti-fungal activity against the saprophytic marine fungus D. salina. Three of the six compounds tested produced inhibitory activity at or below their natural concentration. / by Theresa Meickle. / Thesis (Ph.D.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

This thesis revealed Australian lakes to be richer in chironomid (Diptera: Insecta) species than was previously recognised. A methodology for the collection of chironomid exuviae from lakes was developed using a 12-month study of exuviae from a single lake, Lake McKenzie, Jervis Bay. The method is a rapid and effective way to produce an inventory of species living within a lake. In addition, a distinct biogeographical pattern was detected for chironomid species from a survey of chironomids from southern and eastern Australian freshwater lakes. Geographical location of the lake was more influential on the distribution of chironomid species than was the type of lake. The majority of lake dwelling chironomid species in this investigation were restricted to lakes within one of four geographic lake regions; Tasmania, south-eastern Australian mainland, Fraser Island or tropical north Queensland. A temporal investigation of chironomid exuviae was conducted on a pair of small upland Blue Mountain waterways. Abundance and species richness of exuviae exhibited diurnal patterns. A chemical and macro-invertebrate survey of zinc and sewage organic waste discharges to upland streams in the Blue Mountains detected marked ecological impairment. Macro-invertebrate families responded in different ways to the two different types of waste discharge. According to the family-level results, chironomid larvae responded negatively (reduced abundance) to the zinc pollution and positively (increased abundance) to the sewage pollution. Another major finding from this thesis was that chironomid species assemblages, in the streams surveyed, were strongly impaired by zinc-contaminated mine drainage and sewage effluent. This differed to the family-level larval results. This thesis provided the first Australian evidence that many chironomid species are intolerant of heavy-metal pollution. This research also revealed further evidence that many chironomids species are intolerant of sewage pollution. / Doctor of Philosophy (PhD)

Doctor of Philosophy(PhD) / This thesis uses a political ecology framework to critically analyse how development and environmental orthodoxies influence the use, management and development of living aquatic resources in an information poor developing country context. The research focuses specifically on Lao PDR, the only landlocked country of the Mekong River Basin, to question how knowledge over living aquatic resources is framed by a range of stakeholders. Specific attention is given to how aquaculture has gained ascendancy over capture fisheries in the rhetoric of resources users as well as government and nongovernment organisations. The empirical research focuses on the role of broad scale economic, social and environmental influences over resource use, the practical and perceived importance of both aquaculture and capture fisheries in rural Lao livelihoods and finally, how living aquatic resources are represented within the dominant development agendas of conservation, poverty alleviation and rural development. Field work was conducted in Savannakhet province in Southern Lao PDR over 18 months from 2001 to 2002. The thesis has a strong empirical research base divided into activities carried out over multiple scales ranging from household to the Mekong River Basin. The thesis begins by establishing the historical context of resource use as well as the major orthodoxies on which development is based. Attention then turns to the extensive empirical research conducted over three districts of Savannakhet province. The results of the empirical research report two macro scale studies at the district level. The first is a survey of fish ponds across three districts focusing on the spatial distribution of investment and resource use. The second is a survey of fish trade focusing on the differential trade between culture and capture fish species. The results of both studies highlight the disjuncture between complex patterns of aquaculture and capture fishery use and the major assumptions made about the use of these two resources by policy makers and management. Analysis then moves to the local level focusing on the role and importance of aquaculture and capture fisheries to the livelihoods of rural Lao communities. The results show the instrumental and hermeneutic importance of fish and other aquatic resources in the livelihoods of households and the community. In particular it is shown that capture fisheries are more important to rural livelihoods in terms of income and nutrition, while aquaculture is perceived as a more important activity in the development of community and household economies. ii The final section then compares the empirical findings of the thesis with the policy and planning agendas of government and non-government organisations. The analysis focuses on the role of ideas and agency creating a highly politicised policy environment concluding that aquaculture based policy is more compatible with both government and non government agendas of poverty alleviation and rural development than capture fisheries. Furthermore, capture fisheries are marginalised within conservation as a resource that cannot contribute to the improvement of livelihoods or alleviate poverty. The thesis concludes that living aquatic resources provide an imperative source of food and income to rural communities through diverse and complex human-environment interactions. In contrast government and non-government organisations operating at regional, national and local scales of policy and planning simplify these relationships drawing on wider orthodoxies of aquaculture and capture fisheries development. These simplifications do not reflect the problems and needs of the predominantly rural population. Furthermore, in the absence of a strong empirical base of information, living aquatic resources management and development has become highly politicised. Instead of responding to the realities of resource users, policy and planning reflect the interests and beliefs of development organisations, government and non-government. The thesis provides an important, grounded account of the importance of living aquatic resources to rural livelihoods in Lao PDR and how these resources are understood and translated into national development and management agendas. In doing so the thesis contributes to an understanding of how complex human-environmental systems are perceived and represented in development policy and wider knowledge systems. The thesis also makes an important theoretical contribution to the growing body of literature on critical political ecology by arguing for the revitalisation of ecology as an integrated approach within political ecology and more widely within the study of humanenvironment interaction.