Contaminants such as pharmaceuticals are of increasing concern due to their ubiquitous use and persistence in surface waters worldwide. Limited attention has been paid to the effects of pharmaceuticals on marine life, despite widespread detection of these contaminants in the marine environment. Of the existing studies, the majority assess the negative effects of pharmaceuticals over an exposure period of 30 days or less and focus on cellular and subcellular biomarkers. Longer studies are required to determine if chronic contaminant exposure poses risks to marine life at environmentally relevant concentrations. Also scarce in the literature is examination of whole organism effects to identify potential community-level consequences. Two long-term studies with the antidepressant pharmaceutical, fluoxetine (the active constituent in Prozac®) were conducted to determine whether nominal concentrations detected in estuarine and coastal environments affect organism health and interactions. First, we measured whole organism metrics in the California mussel, Mytilus californianus over a period of 107 days. Specifically, we measured algal clearance rates, growth, and condition indices for both reproductive and overall health. We found that fluoxetine negatively affects all measured characteristics, however many effects are mediated by length of exposure. Perhaps the most notable result was that mussels spiked with fluoxetine cleared less algae after 30 days of exposure. Reduced growth and condition indices likely are a consequence of improper nutrition among fluoxetine-treated mussels. Any level of fluoxetine significantly affected the gonadosomatic index after 47 days. The results from this study on mussels fill an important data gap, highlighting organism-level effects of chronic exposure periods; such data more explicitly identify the impacts of pharmaceuticals and other contaminants on marine communities and ecosystems. Fluoxetine has also been documented to affect the behavior of fish and invertebrates, including freshwater and marine bivalves, crustaceans, and fish. Given that other crustaceans exhibited increased activity levels under fluoxetine exposure, we hypothesized that this would subject them to greater predation risk. In our second exposure study, we assessed whether a similar range of fluoxetine concentrations used in the mussel study altered the risk behavior of the Oregon mud crab, Hemigrapsus oregonensis, in response to a common predator, the red rock crab, Cancer productus. We conducted this study for 60 days, conducting day and night behavioral trials (with and without predators) four times a week. We found that crabs exposed to any amount of fluoxetine (3 or 30 ng/L) had increased activity levels relative to controls; however behaviors of 3 ng/L-spiked crabs were not always significantly different from controls. Among control crabs, day and night trials yielded similar results, where a clear response to the addition of the predator was observed. Crabs dosed with fluoxetine exhibited more foraging and active behaviors in the presence of the predator. Additionally, crabs spiked with fluoxetine at 30 ng/L had the greatest risk of mortality either by predation by red rock crabs or due to more aggressive behaviors among conspecifics. The results of this study shed light on a particularly unexplored area of contaminants research: how do psychoactive pharmaceuticals affect animal behavior when exposed to the low concentrations persisting in the aquatic environment for a prolonged period of time?

The relationships between brook trout (Salvelinus fontinalis), brown trout (Salmo trutta), non-game fish populations and selected physical and chemical parameters were investigated in four streams draining the Blue Ridge Mountains in north-central Virginia during low flow conditions in August, 1981 and 1982. Multiple regression and discriminant function analysis identified average stream width and maximum stream temperature as the main environmental factors related to brook and brown trout abundance and distribution. Furthermore, consistent fish species assemblages relative to brown trout distribution were observed in the study streams. The movements of tagged brown trout in two streams were assessed for the period from June 1981 to July 1982. Most brown trout remained within 200 m of original tagging sections, 98.7% in the Conway River (78 out of 79) and 71.4% in the North Fork Thornton River (7 out of 9). The 1979, 1978 and 1977 year class fish (ages 2+, 3+ and 4+) exhibited extremely restricted movements and were invariably recaptured at original capture locations while the 1980 year class (age 1+) displayed small net upstream movements (<80 m) throughout the period. Two 1980 year class individuals displayed extensive movements (17.0 km downstream and 1.2 km upstream). These movements were characteristic of other stream resident brown trout populations. Results of this study suggest that brown trout may expand their range upstream into currently allopatric brook trout zones. It would likely be a slow but steady process which could be accelerated by infrequent long-range movements. The potential for establishment of reproducing brown trout populations and impacts of brown trout on native brook trout populations can be assessed utilizing fish species assemblages, average stream width and maximum stream temperature prior to further brown trout introductions in this region of Virginia. / Master of Science

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Ecology and Biodiversity / Master / Master of Philosophy

Baigiamajame magistro darbe nagrinėjamas ką tik nuo atliekų šalinimo konvejerio nuimtas, neatvėsęs ir nesusihidratavęs ekstrakcinis pushidratis fosfogipsas. Tai pati gausiausia mineralinė atlieka, kurios sąvartynai sparčiai auga, o panaudojimas lig šiol nėra išspręstas. AB “Lifosa” kasmet į sąvartynus šalina daugiau kaip 1 mln. tonų E-PG, o su kiekviena tona prarandama apie 160 kWh jame akumuliuotos atliekinės energijos. Todėl būtina ieškoti efektyvių būdų jam perdirbti neleidžiant sunykti atliekinei energijai. Tokio pavidalo, kokio fosfogipsas šalinamas į sąvartynus, jis negali būti naudojamas statyboje dėl jame esančių priemaišų (nesureagavęs apatitas, H3PO4 ir H2SO4 likučiai, CaS, geležies, aliuminio druskos). Dėl šių priemaišų poveikio fosfogipso bandiniai labai lėtai kietėja ir pasižymi nedideliu tankiu ir stipriu, dideliu vandens įgeriamumu. Darbe pasiūlytas ir išbandytas mechaninės aktyvacijos būdas, neleidžiantis pushidračiame fosfogipse akumuliuotai atliekinei energijai sunykti. Nustatyta, kad tiek neaktyvuoto, tiek aktyvuoto fosfogipso bandinių stipriai mažai priklauso nuo išlaikymo trukmės, o bandinių, suformuotų iš gipscemenčio stipriai pastebimai didėja. Vandens poveikis skirtingos formavimo masių sudėčių bandiniams yra nevienodas: fosfogipso bandiniai prarado pradinę formą ir iš dalies arba visiškai stiprį, tuo tarpu gipscemenčio bandinių forma nepakito, o stipris sumažėjo nežymiai. Analizuojant kietėjimo deformacijų duomenis, matyti, kad kietėjimo deformacijos... [toliau žr. visą tekstą] / The main magistracy final work motivation and aims: The main goal was to implementation a pilot project for use of surplus energy accumulated in E-PG. Phosphogypsum is one of the most abundant mineral waste materials, the use of which is solved fully up to the present time. In spite of the fact, that there are tens of millions of tons of phosphogypsum accumulated in stacks, an additional million tons of E-PG is added each year. Due to the fact, that during the phosphoric acid production process from apatite phosphogypsum is formed in the hemi hydrate state (CaSO4  1/2 H2O) similarly like construction gypsum, therefore it could be used in construction work as a gypsum binding material. However the acids present in the E-PG compositions block the hydratation and hardening processes. Various technological solutions such as washing out the soluble admixtures or neutralization with slaked lime suspensions increase the energy expenditures substantially. Energy requirements then increase by almost two times to produce a gypsum binding material in comparison to when natural gypsum materials are used. Correspondingly the energy costs increase and pollutant emissions into the environment. Taking into account these conditions, we investigated the E-PG properties when mechanical activation method was used. It allows obtaining chemically active formation mixtures with out using fuel or other sources of heat energy. However from a technological point of view, if we store E-PG for longer... [to full text]

Mercury (Hg) is a toxicant of global concern, but few strategies exist to evaluate its biological effects on the ecosystem. Piscivorous wildlife, such as mink (Mustela vison), are particularly at risk because they can bioaccumulate Hg to concentrations known to impair neurological systems. Given that biochemical changes in the brain precede functional and structural impairments, I evaluated the use of neurochemicals as early-warning biomarkers of Hg toxicity in mink. Initial studies demonstrated that neurochemical biomarkers could be measured from mink carcasses collected from the field, as long as factors such as storage temperature and freeze thaw cycles were accounted for. To determine if Hg could directly impair neurochemicals in mink, an in vitro study demonstrated that Hg (HgCl2 and MeHg) could inhibit radioligand binding to the muscarinic cholinergic (mACh) receptor in the cerebellum and cerebral cortex regions of the brain. By analyzing whole brains collected from wild mink, it was demonstrated that a significant positive correlation existed between concentrations of brain Hg and levels of mACh receptors. These field observations were confirmed by results from a controlled methyl Hg (MeHg) feeding trial in captive mink, whereby sub-chronic exposure of mink to 0.5 - 2 ppm MeHg (ecologically relevant levels) resulted in significant increases in acetylcholinesterase activity and mACh receptor levels in specific brain regions. Collectively, these results demonstrated that exposure of mink to environmentally realistic concentrations of Hg can be related to alterations in neurochemicals at multiple tiers of biological organization. Given the importance of a functional nervous system in wildlife health, the physiological and ecological significance of these findings need further exploration. The results demonstrate that neurochemical approaches may be novel biomarkers to assess the ecotoxicology of Hg, and by extension, other pollutants o

Flooding cycle in wetland rice (Oryza sativa L.) production systems is often subject to seasonal and cultural variations which may affect the availability and uptake of nitrogen in different ways. These factors may more or less influence the physiological and growth responses of the plant. In an effort to improve productivity in rice cropping systems, two controlled environment studies and a field trial were conducted to evaluate the growth and yield responses of rice to different flooding regimes and nitrogen fertilizer management strategies. In the first glasshouse trial, an upland cultivar (GM-1) was used to study the effects of four flooding regimes and three nitrogen application rates on the tillering, yield components and grain yield of rice. The field study determined the applicability of the results of the glasshouse trial to out-door environmental conditions, with the aim of gaining further insight into the impact of nitrogen application strategy on tiller and grain qualities. Two wetland cultivars (FKR-19 and N-19) and GM-1 were used to evaluate the effects of two flooding regimes and two nitrogen topdressing patterns. The second glasshouse trial determined the effect of hydro-priming on the establishment of direct seeded rice, and the effect of flooding on aerenchyma formation in rice roots. Results of the studies showed that flooding with standing water of 5 cm above the soil surface, irrespective of when it occurred, and nitrogen application increased the number of tillers and panicles, above ground dry matter, nitrogen uptake and grain yield of rice. However, late flooding and high nitrogen application rate of 220 kg ha-1 were found to encourage the production of late tillers, thereby reducing the efficiency of nitrogen use for grain production. Nitrogen application in three split doses tended to increase plant nitrogen content at heading; it slightly increased the protein content of the grains at maturity, but reduced the amylose content of the starch granules. Nitrogen application in two split doses led to increased grain yield in non-flooded plants, while the three-split treatment increased nitrogen uptake and grain yield in the flooded plants. Flooding significantly increased aerenchyma formation in the cortical tissues of rice roots, particularly at 50 mm behind the root tips. Hydro-priming seeds for 48 h improved plant establishment by shortening the germination and emergence times, and increasing the height and dry matter accumulation of seedlings, thereby ameliorating the susceptibility of rice to flooding stress. Overall, the thesis affirmed that controlled flooding is beneficial to rice production since it enhanced the growth and yield of the plant. It further revealed that early flooding and appropriate timing of moderate nitrogen application can ensure the conservation of water and nitrogen resources, including the quality of the environment, with no significant consequence for yield and productivity of the crop. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

This dissertation outlines the contribution of evolutionary and environmental factors on North American freshwater fish morphological variation. A more thorough understanding of the factors which result in morphological variation is essential to describing patterns of evolutionary diversification, distribution, ecological niche, ontogeny, sexual dimorphism, ecosystem role, community assembly, invasion dynamics, and conservation. This dissertation makes a unique contribution to understanding morphological diversity in freshwater fishes by linking intraspecific and interspecific variation to phylogeny, allometry, sex, habitat niche, geographic niche, hydrology, and long term environmental change. This dissertation is comprised of three chapters which detail large scale macroevolutionary patterns in morphological variation for North American freshwater fishes, long term morphological changes with hydrological alterations in Cyprinidae, and phenotypic plasticity of freshwater drum in the Wabash River. Overall, North American fishes tend to be deeper bodied and more robust with larger body size, in females, in low flow and lentic hydrological conditions, and in taxa with smaller geographic range that occupy more specialized habitat niches. Further, macroevolutionary analysis suggests that the majority of morphological diversification occurred relatively early on in the evolutionary history of North American fishes. / Evolution of North American freshwater fish morphology with variation in habitat use and geographic range -- 100 years of hydrologic alterations and morphological variation in Cyprinidae -- Effects of allometry, sex and river location on morphological variation of freshwater drum Aplodinotus grunniens in the Wabash River, USA. / Department of Biology

Copies of author's previously published articles inserted. / Bibliography: leaves 317-359. / xxii, 360 leaves : ill. (some col.), maps (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Examines the generality of the Flood Pulse Concept as a model for the role of flow in large floodplain rivers of all climatic zones and reviews the literature on hydrology-biology relations, with particular reference to the ecology of riverine fish. Using techniques of ordination, clustering and analysis of similarities (ANOSIM), examines the relations between flow variability, econology and climate in large rivers worldwide. Using a fie-year database for Cooper Creek in Central Australia, relates structures of fish, macroinvertebrate and zooplankton assemblages and indices of fish health and behaviour to hydrology at several spatial and temporal scales. These relations are established using multivariate techniques, univariate correlation and regression, and neural networks modelling. / Thesis (Ph.D.)--University of Adelaide, Dept. of Zoology, 1999

Copies of author's previously published articles inserted. / Bibliography: leaves 317-359. / xxii, 360 leaves : ill. (some col.), maps (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Examines the generality of the Flood Pulse Concept as a model for the role of flow in large floodplain rivers of all climatic zones and reviews the literature on hydrology-biology relations, with particular reference to the ecology of riverine fish. Using techniques of ordination, clustering and analysis of similarities (ANOSIM), examines the relations between flow variability, econology and climate in large rivers worldwide. Using a fie-year database for Cooper Creek in Central Australia, relates structures of fish, macroinvertebrate and zooplankton assemblages and indices of fish health and behaviour to hydrology at several spatial and temporal scales. These relations are established using multivariate techniques, univariate correlation and regression, and neural networks modelling. / Thesis (Ph.D.)--University of Adelaide, Dept. of Zoology, 1999