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1. Movement shapes the lives of animals and their interactions with human activities. In recent decades, the emergence of movement ecology as a discipline and developments in electronic tagging and tracking have led to substantial improvements in our understanding of animal movement and its implications for species conservation. Yet while research has burgeoned for many taxa, including sharks, other groups in aquatic ecosystems, such as skate (Rajidae), remain comparatively understudied. 2. The flapper skate (Dipturus intermedius) is a large, Critically Endangered elasmobranch. The species has been extirpated from much of its former range, but individuals are still found off west Scotland where the Loch Sunart to the Sound of Jura Marine Protected Area (MPA) has been designated for flapper skate conservation. However, skate movements within and around the MPA remain poorly understood. 3. This thesis investigates the movements of flapper skate in relation to the MPA using electronic tagging and tracking data from passive acoustic telemetry, archival (depth and temperature) tags and mark-recapture angling. Objectives include the examination of site affinity, vertical movements and responses to disturbance. Research in these areas motivates the development of a flexible, mechanistic modelling framework for passive acoustic telemetry systems. 4. For flapper skate, the key finding is the prevalence of site affinity to the MPA. Vertical movements are shaped by depth-specific periodic behaviours and individual variation. These movements can be perturbed by angling, but on the whole skate appear to be behaviourally resilient to this practice. 5. Beyond flapper skate, this thesis highlights multifarious uses of electronic tagging and tracking data, brings underutilised analytical methods to the attention of the movement ecology community and establishes a holistic framework for movement modelling in passive acoustic telemetry systems. This work demonstrates the wide-ranging contributions of species-specific studies in the fields of movement ecology and conservation.

Flow injection apparatus was designed based on the use of selective reaction chemistry and sulphur specific flame photometric detection. The performance of two reaction systems was assessed using seven synthesised dimethylsulphonium compounds (dimethylsulphonio propionate (DMSP), dimethylsulphonio-2-methyl propionate, S-methyl methionine (SMM), dimethylsulphonio acetate, dimethylsulphonio butanoate, dimethylsulphonio pentanoate, dimethylsulphonio choline). Base hydrolysis was found to be selective towards dimethylsulphonio propionate, whilst sodium tetrahydridoborate (borohydride) gave a virtually equal response to all seven compounds. Two HPLC instruments were developed based on the reaction chemistries and detection systems employed in the flow injection apparatus. The chromatographic separation of the seven synthesized DMS precursor compounds on both anion- and cation-exchange media was evaluated for the identification of DMS precursors. This apparatus provides the basis for the first reliable identification of DMS precursor compounds at trace levels. The 3σ detection limit employing base hydrolysis is 1.29 x 10⁻⁷ mol(DMSP) dm⁻³ (200 μl injected), corresponding to an absolute injected mass of 3.5 ng (DMSP). Macroalgae, microalgae, flowering plants, barley and cyanobacteria were analysed for DMS precursor compounds. DMSP was identified as being present in a wide range of flora at concentrations of between 2.9 μmol kg⁻¹ fresh weight (FW) and 29.4 mmol kg⁻¹ FW. The instability of DMSP towards enzymatic and chemical breakdown requires particular attention to be given to sample collection and storage. An extraction method was developed involving 2% HC1 to deactivate DMSP- consuming enzymes and to slow chemical hydrolysis. The results constitute the first direct sulphur specific measurements of DMSP at trace levels. In macroalgae, levels ranged from 0.0010 to 29.4 mmol(DMSP) kg⁻¹ FW. For plankton levels between 0.82 to 158 μmol(DMSP) mg(chl'a')⁻¹ were recorded. SMM was found in cabbage and parsley (74.32±7.00 and 16.11 ± 0.78 μmol kg⁻¹ FW respectively) and these results constitute the first direct measurements of SMM at trace levels.

Many organisms must contend with navigating their environments from birth. An organism could be classified as – and is often studied – in the context of locomotion through a single habitat type. However, many organisms must contend with a wide variety of environmental obstacles and substrates. What’s more, a large group of animals, Lissamphibia, do so while undergoing drastic transformation of their morphology and locomotor appendages. This transformation, term metamorphosis, typically coincides with a movement from water as a tadpole, to land as a frog or salamander. Many studies have associated this transitionary period with decreased locomotor performance and worse survival compared to amphibians pre or post metamorphosis and have termed this paradigm as the “Adaptive Peaks Hypothesis”. This body of work sought to address the generality of the Adaptive Peaks Hypothesis by studying the locomotor performance, development, and survival of a fully aquatic frog, Xenopus laevis. Swimming performance and survival of frogs across developmental stages were measured using high speed cameras and a predation tank where morphological traits were compared between (non)survivors post predation. Another subset of frogs, including aquatic X. laevis and more terrestrial L catesbianus, were used to quantify bone mineral density and material properties of developing frogs. Finally, the aquatic frog, Xenopus laevis, underwent jumping performance trials using high speed cameras and force plates to determine how well an aquatic frog could perform out of the water. The adaptive peaks hypothesis is not as robust as once thought. Xenopus laevis did not experience a performance decrease during metamorphosis, despite similar capture rates from the predators. Furthermore, the bone development of the femur differed from the more terrestrial frogs such that the less dense bones had greater stiffness in Xenopus. Finally, despite being fully aquatic, Xenopus frogs were still capable jumpers across two incline treatments with greater variability in jump performance in the more juvenile stages. Taken together, this body of work builds upon our understanding of animal locomotion by addressing how animals with complex life cycles navigate complex habitats.

Crude oil commonly enters freshwater aquatic ecosystems as thin sheens forming on the water surface. Oil contains mixtures of toxic compounds called polycyclic aromatic hydrocarbons (PAHs), some of which are known to be photodynamic, increasing toxicity when combined with ultraviolet radiation. Benthic macroinvertebrate communities are commonly utilized as bioindicators, and as such rely on abundant data in literature concerning benthic macroinvertebrates' relative tolerances to a wide range of pollutants. A series of 10 plastic traps, half of which were filtered from UV radiation, were deployed in an urban pond for 27 days to determine colonization preferences of benthic macroinvertebrates to UV exposure. Results of this in situ experiment indicated that the majority of aquatic insects collected from traps inhabited the UV exposed treatment group, particularly the nonbiting midge, Chironomidae. A series of bioassays were then completed to investigate the sensitivities of a Chironomidae species to thin sheens of crude oil in the presence and absence of UV radiation. All bioassays were conducted using 10 day old Chironomus dilutus larvae cultured in the lab. The series of C. dilutus bioassays were all conducted under the same water quality parameters, temperatures, and oil sheen dosing methods, under a 16:8 photoperiod and exposed to 16 h UV per day. Five replicates (n = 20) were loaded into 350 mL glass crystallizing dishes and exposed to four treatments for 96 hours: no UV/with sheen, with UV/no sheen, both UV and oil sheen, and a control. Three assays with 175 mL water volume were completed, one with no sediment, one with silica sand, and one with fine sand. Sediment type had a significant effect on mortality (p < 0.0001), but significant effects of UV or PAHs were not found. Two more C. dilutus assays were completed with identical parameters as the latter two with sediment, except a decreased water volume of 90 mL was used to bring the sheen closer to sediment. There was a significant effect of PAHs on mortality (p = 0.0003), however, no clear trend showing PAHs driving mortality. Results showed no significant effects of UV, sediment type, or relationship between UV and PAHs. A final bioassay was completed to compare phototoxic effects of PAHs on pelagic organisms with benthic organisms. This bioassay used test species Daphnia magna, for a 48 h exposure period with five replicates (n = 10), 8 h UV exposure and 16:8 photoperiod. All individuals in the control group and UV only group exhibited 0% mortality, and with sheen/with UV treatment group resulted in 100% mortality following the 48 h exposure. The results of the D. magna exposure showed significant effects of PAHs (p < 0.0001), UV (p = 0.037), and photoinduced toxicity (p = 0.024), and were consistent with similar bioassays in the literature. This study suggests that C. dilutus are at low risk to photo-induced oil sheen toxicity.

Per- and polyfluoroalkyl substances are persistent chemicals that present risks to human environmental health as a result of their ubiquitous nature. These compounds also impact laboratory based exposure and toxicology experiments through PFAS contamination in common materials used for aquatic laboratory exposure experiments. This thesis reviews literature surrounding PFAS bioaccumulation in aquatic organisms in laboratory exposure studies using several measures such as the bioaccumulation factor, bioconcentration factor, biomagnification factor, rate of uptake, and elimination rate. Lack of standardization in how the bioaccumulation factors were calculated creates challenges in statistical comparisons. This thesis also investigates potential PFAS contamination and impacts on aquatic laboratory based exposure experiments in habitat materials, fish feed, and aquaculture fish. Results suggest that PFAS contamination is present in common fish feed and can also be found in aquaculture fish. Unaccounted PFAS contamination in bioaccumulation and toxicity studies could confound results and ultimately influence environmental health recommendations.

Abstract: Hydraulic fracturing is an unconventional oil and gas extraction method used to liberate oil and gas reserves from low permeability geological formations by injecting large quantities of fracturing fluid into the well-bore under high pressures. A by-product of this process is flowback and produced water (FPW), a chemically complex and heterogeneous wastewater mixture. Spills and releases of FPW to surface bodies of water is an environmental topic gaining increasing public attention. Freshwater animals are extremely sensitive to FPW, with saline components of the solution responsible for a considerable proportion of the induced lethality. However, other chemical constituents besides saline components (e.g., metal species and numerous toxic dissolved organic compounds, including polycyclic aromatic hydrocarbons [PAHs], organophosphorus compounds, and alkyl ethoxylate carboxylate surfactants) appreciably contribute to the overall toxicological potential of FPW. I demonstrated that in rainbow trout (Oncorhynchus mykiss; RT) acutely exposed to FPW, significant induction of key phase I and II xenobiotic metabolic processes occurs (ethoxyresorufin-o-deethylase activity and cytochrome P450 1A, UDP-glucoronosyl transferase and glutathione-s-transferase transcript expression), implying that biotransformative responses are induced to detoxify organic compounds (specifically PAHs). Furthermore, increased reactive oxygen species is another major physiological stress encountered in FPW exposed organisms while elevated expression of vitellogenin and estrogen receptor α2 genes also demonstrate possible endocrine disruptive effects in exposed organisms. I additionally examined hepatic nutrient handling and energy dynamic processes in FPW exposed RT and showed that an immediate deviation in nutrient handling occurs following/during FPW exposure in trout. Embryonic exposure studies revealed that the development and function of cardio-respiratory systems in fish are severely impacted by acute FPW exposure. FPW significantly increased rates of numerous developmental deformities at hatch (including rates of pericardial edema) and decreased heart rates in zebrafish (Danio rerio; ZF) embryos. FPW-mediated impacts to embryo metabolic O2 consumption (MO2) were additionally displayed to persist through development and past initial acute exposures in both ZF and RT. Embryos from both species of fish also displayed elevated expression of critical cardiogenic development and differentiation transcription factors and altered expression of atp2a2a (a key cardiac Ca2+ ATPase required for proper cellular Ca2+ cycling and transport during an excitation-contraction coupling event) following acute FPW exposures. RT embryos additionally displayed altered expression of other cardiac electrochemically related genes responsible for the transport of ions required for action potential propagation and completion, including scn5lab, kcnh6, and kir2.1. These transcriptional changes agree with cellular studies on isolated ventricular mahi mahi (Coryphaena hippurus) cardiomyocytes exposed to low-strength FPW dilutions displayed reduced sarcomere contraction sizes and altered relaxation indices. Finally, I identified that embryonic exposures to FPW significantly decrease juvenile fish swimming performance (Ucrit), with corresponding decreases in maximum metabolic rates and aerobic scope. Additionally, embryonic FPW exposure reduced ventricular compact myocardium thickness that may contribute to the latent effects of embryonic FPW exposure on juvenile fish swimming performance and respirometry. Overall, these results highlight the considerable toxicity of FPW to organisms of aquatic environments and reveal cardio-respiratory development and function in fish as targeted processes affected by FPW exposure.

Abstract: Ecological stoichiometry is a framework that allows explicit consideration of nutrient restrictions on growth, and can be used to answer important ecological questions. First, we consider the impact of the turnover rate of producer biomass on ecosystems, since it is usually much faster in aquatic ecosystems than terrestrial. The WKL model uses ecological stoichiometry to describe the flow of phosphorus and carbon through a producer-grazer system, hence varying the model parameters allows for analysis of different ecosystems of this type. Here we explore the impacts of the intrinsic growth rate of the producer and the maximal ingestion rate of the grazer on these dynamics. Simulations show that for low intrinsic growth rate and maximal ingestion rate, the grazer goes extinct; for higher values, coexistence occurs in oscillations. Analyses show that the persistence of terrestrial grazers despite lower turnover times likely relies on additional factors, such as light intensity and grazer loss rate. Second, we extend the WKL model to allow for consideration of the impacts of elevated atmospheric carbon dioxide concentration on producer-grazer dynamics. Three new models are developed, with varying amounts of system openness to carbon as well as consideration of different impacts of elevated atmospheric carbon dioxide concentration on photosynthesis. The most basic of these models is analysed further using primarily local bifurcation analysis. Overall, these analyses show that increased carbon sequestration and decreased stoichiometric quality of producers would require sufficient amounts of other factors necessary for photosynthesis.

In-situ fluorometry sensors offer a new means of estimating total algal biomass by measuring the fluorescence of photosynthetic pigments like chlorophyll-a. Researchers and water quality monitors, such as the National Estuarine Research Reserves (NERRs), are broadly deploying these new total algae sensors to augment current grab sample spectrophotometry techniques with high frequency sensor data. However, field performance assessments for these new sensors are limited, with potential for site-specific environmental parameters to interfere with chlorophyll-a fluorescence measurements. In this assessment, I examine the effectiveness and applicability of the YSI Total Algae probe for use in Old Woman Creek National Estuarine Research Reserve and other NERRs across the country. I also attempt to quantify and correct for interferences with sensor readings due to attenuation effects from water temperature and turbidity using controlled lab tests of deionized water and live water samples from Old Woman Creek. I then developed multiple correction models based on these lab tests, with the end goal of creating a strong correlational model between paired field measurements of in-situ fluorometric chlorophyll-a and ex-situ spectrophotometric chlorophyll-a collected over a 3 year period. Correction models were tested against uncorrected sensor values using simple linear regression analyses and Akaike Information Criterion (AIC) tests. I was unable to develop a strong correction model for temperature and turbidity, with the best full dataset correction model (r2=0.441) barely improving upon the uncorrected model (r2=0.440). However, additional models created with a "best-case" dataset that subset the full dataset to include only measurements with similar conditions to the live sample lab tests resulted in significant model improvements in corrected (r2=0.663) and uncorrected (r2=0.655) models. The lack of improvement between corrected and uncorrected models could be due to multiple compounding factors, including incident light refraction in turbidity tests, a chlorophyll-a concentration effect in temperature tests, and an algal colonial behavior effect throughout lab and field measurements. The improvement of models between the full dataset and best-case dataset highlights the importance of site-specific calibration and consideration of dynamic characteristics in coastal estuaries. In-situ fluorometry sensors are powerful tools for high frequency total algae sampling, but researchers and water quality monitors must be cognizant of interference effects and the site-specific limitations of these new methods.

The generalized bio-optical transition from oligotrophic blue to mesotrophic green waters has enabled remote measurement of oceanic ecosystems under conditions in which the optically relevant water mass constituents covary with the primary phytoplankton photopigment, chlorophyll a (Chla). This assumption, known as case-1, is generally incorrect within coastal and inland water bodies, where external factors, such as riverine discharge and sediment resuspension, also modify the concentrations of organic and inorganic constituents beyond the ranges anticipated for natural oceanic ecosystems. New approaches to characterize aquatic ecosystems without relying on case-1 criteria are proposed here using measurements of apparent and inherent optical properties. The methods applied in this work include bio-optical modeling and analyses of in situ, airborne, and satellite radiometric measurements of oceanic, coastal, and inland water ecosystems. Key findings are that: satellite phytoplankton datasets underestimate phytoplankton biomass in coastal ocean regions when default atmospheric correction methods are applied (Chapter 1); the expansion of spectral range for above-water radiometric measurements improves the accuracy of colored dissolved organic matter algorithms (Chapter 2); and hyperspectral beam-attenuation meters can accurately predict Chla without relying on empirical relationships between organic and inorganic particle populations (Chapter 3). The bio-optical advances presented here improve measurement capabilities for optically complex waters and are relevant to global (i.e., oceanic, coastal, and inland) water bodies. Finally, this work supports the perspective that bio-optical approaches should be consistent with electromagnetic theory or other fundamental principles - rather than requiring a partition between waters that satisfy versus fail empirical open ocean criteria - to incorporate a greater diversity of global aquatic ecosystems.

Terrestrially-derived dissolved organic matter (t-DOM) is one of the largest reservoirs of reduced carbon on the planet with approximately 2.5x1014 g-C entering the global coastal oceans annually. This carbon pool is largely derived from the products of vascular plant degradation, such as humic and fulvic acids, which are recalcitrant due to their enrichment in aromatic moieties. As t-DOM travels through riverine systems to the coastal oceans it becomes increasingly refractory as riverine microbial communities preferentially oxidize the most bioavailable components. However, most chemical tracers diagnostic of t-DOM (e.g. lignin-derived phenols) are removed before reaching the open oceans, suggesting that this material is transformed in the coastal margins. Microbial transformations are expected to contribute to the disappearance of t-DOM in these systems, but the mediating factors and mechanisms are presently unknown. The work described in this dissertation aims to understand how coastal microbial communities degrade t-DOM. Within, I show that a concept well studied in soil systems, the priming effect (PE), may help explain the disappearance of t-DOM in these systems. PE occurs when the presence of a labile carbon source and/or nutrients stimulates the degradation of a recalcitrant carbon source. I focused my studies on coastal margins of the Southeastern United States. These systems represent a transition zone between riverine systems, carrying recalcitrant t-DOM, and marsh systems, which are sites of new production and contain small yet labile carbon pools. As such, they are ideal study sites in which to investigate whether coastal microbial communities can indeed be primed. A first study employed a mesocosm experiment to demonstrate that PE could be invoked in a natural coastal microbial community. A second study demonstrates that concentration and type of labile carbon influence the magnitude, timing and sign of PE in a species-specific manner. Finally, metatranscriptome-based field studies provide evidence that coastal marsh microbial communities are actively catabolizing aromatics and carbohydrates common to the systems. Collectively, these studies enhance our understanding of the mechanisms through which estuarine communities transform t-DOM and provide insights and future directions for continued study in the field.

Climate change and eutrophication alter the structure and function of ecosystems; however, the interactive effects of these two stressors are poorly understood. In particular, we lack understanding of how the quantity and stoichiometry of essential nutrients such as nitrogen (N) and phosphorus (P) shape ecosystem responses to warming. Predicting these responses will require a mechanistic understanding of how nutrient availability shapes autotrophic functional groups, nutrient acquisition, and subsequently controls ecosystem response to warming. Because stream biofilms (a matrix of algae, bacteria, fungi, and detrital matter) represent an important component GPP and therefore control the flux of energy and nutrients through aquatic and global ecosystems, improving predictions of GPP and subsequent ecosystem response to warming will require developing a mechanistic understanding of biofilm response to N and P supply.To evaluate how nutrients mediate the temperature dependence of GPP, we conducted three successive stream-side channel experiments to develop biofilm communities across wide gradients of N concentration (0-14.3 µM), P concentration (0-6.5 µM), N:P ratios (

A study of Asian clam (Corbicula fluminea Müller) colonization in relation to changes in aquatic vegetation community as a result of management of Hydrilla verticillata (L. f.) Royle with grass carp was conducted at the Lewisville Aquatic Ecosystem Research Facility (LAERF), Lewisville, TX, from April 2015 through October 2016. Percent vegetation cover, C. fluminea abundance and water quality metrics (pH, turbidity, conductivity, DO, calcium, chlorophyll a) from 16 experimental subjects were analyzed. Treatments included four replicated grass carp stocking densities; 1-control with no fish stocked (n = 4), 2-low density of 40-43 fish per vegetated ha (n = 4), 3-medium density of 72-81 fish per vegetated ha (n = 4) and 4-high density of 110-129 fish per vegetated ha (n = 4). Data analysis showed statistical significance in the relation of C. fluminea abundance to percent vegetation cover (multiple linear regression, r2 = 0.820), grass carp stocking densities (two-way analysis of variance, p =

The field of Aquatic Toxicology has produced diverse studies on contaminants of emerging concern (CECs). Investigations have brought to light a plethora of knowledge on the subject; of particular interest are those involving pathways by which CECs arrive in waterways (source), the concentrations which they exist therein (fate), and to what extent they affect aquatic animals (effect). Particularly concerning CECs are pharmaceuticals that find their ways into aquatic environments, as these compounds are inherently biologically active and often stable in aqueous solution. Interest in potential adverse effects on exposed animals has begun to yield compelling evidence supporting behavioral and developmental disturbances in addition to physiological and anatomical pathologies. In an attempt to identify anomalies as a consequence of pharmaceutical exposure larval fathead minnows were examined in conjunction with the common panfish, Lepomis macrochirus (colloquially the bluegill sunfish), as models to build on prior evidence. The pharmaceuticals intended for investigation in my experiment are those representing multiple modes-of-action and were administered at concentrations found downstream of wastewater treatment plant (WWTP) effluent discharges. Fathead minnow exposed to 2000 ng/L diclofenac in a 21-day static exchange experiment were found to have inhibited foraging efficiency in a 60 second timed trial. Hepatocyte vacuole proliferation was found in bluegills exposed to methocarbamol (4000 ng/L) or sulfamethoxazole (2000 ng/L), while those exposed to a mixture of all pharmaceuticals or temazepam (2000 ng/L) experienced subdued plasma cortisol and hematocrit (temazepam only) concentrations.

ü Best Management Practices storm water ponds (BMPs) are ways of controlling and filtering storm water and storm sewer effluent. Urbanized areas are increasingly turning to the use of these BMPs as a means to mitigate the affect of storm water runoff on aquatic environments. However, the effectiveness of BMPs is not well understood and there have been few studies that look at the biological efficacy of these filtration systems. This study looked at the effectiveness of three BMPs in the cities of St. Paul and Minneapolis, MN. The BMPs being studied used iron filings blended with sand as a filtration substrate. Water was collected at winter snow melt, spring rain event, and summer rain event. Collected water was used to expose Daphnia magna and Pimephales promelas. D. magna exposure endpoints were survival and reproduction. Daphnia were exposed for 16-day periods to establish adult survival and neonate production. P. promelas exposure endpoints were larval c-start performance, growth, and feeding assays. Larval P. promelas were exposed to stormwater for 21-days before assessing their endpoints. Water chemistry indicates that there is an improvement in water quality from the Inflow to Outflow in each BMP. However, there were few significant differences in larval minnow or Daphnia performance results between the Inflow and Outflow of the BMPs for all three storm water sampling events. The only area that showed marked improvement was larval performance over time, with minnows exposed to water collected later in the year performing better on predator escape assays than minnows exposed to winter snow melt. The design of the BMP filtration system may need to be improved or more filtration may be needed to achieve improvements in biological outcomes.

Lake Catherine is a reservoir located downstream of a historic mine near Hot Springs, Arkansas. The reservoir has received inputs of a range of metals associated with mining, including vanadium (V). The toxicity of V in freshwater sediments is poorly understood. In order to evaluate the success and potential need for continuing remediation efforts in Lake Catherine, a toxicity threshold for V needs to be established. This study evaluated the toxicity of V to laboratory cultured Hyalella azteca, a species commonly used in sediment toxicity tests. H. azteca were exposed to V spiked sediments and site sediments from Lake Catherine, with whole sediment V concentrations ranging from 0 ug/g dw to over 2000 ug/g dw. Mortality and growth were assessed following a 28-day chronic toxicity test to establish lethal and effect concentrations. Mortality was the only endpoint with significant results in the spiked sediment tests, resulting in a sediment V LC50 of 742 ug/g and a pore water V LC50 of 1870 ug/L. Pore water was the best predictor of total V and V+5 bioaccumulation in H. azteca for spiked sediments (r2 = 0.8949 and 0.8934, respectively). Significant toxicity was not observed with site sediment exposure to H. azteca. These results suggest that V toxicity occurs due to pore water exposure. Further, the results suggest that Lake Catherine is not toxic to H. azteca, despite the sediments high V concentrations.

To ventilate their gills, ray-finned fishes (Actinopterygii) use pumps in their buccal and opercular chambers to alternate between positive and negative pressures, driving water over the gills in a unidirectional current. The basic mechanics are conserved across Actinopterygii, but there is considerable morphological and functional variation of the buccal and opercular pumps. I used comparative approaches to investigate the evolution of ventilatory morphology and function across actinopterygians. In the first chapter, I reconstructed the evolutionary history of restricted gill openings across 433 actinopterygian families using recently published molecular data. Restricted gill openings have evolved at least 11 times among ray-finned fishes with diverse morphology and ecology. Fishes with restricted gill openings also occupied a larger cranial morphospace than fishes with other morphologies. In the second chapter, I studied the gill ventilation of the goosefish, Lophius americanus, which exhibits extremely slow ventilation. I found that the inspiration phase of ventilation is greatly increased relative to that of typical fishes, and that, during this phase, the branchiostegals slowly expand. I described the specialized musculature of the gill opening, which has functional and systematic implications for Lophius. In the third chapter, I studied ventilation function among four sculpins and found considerable variation in buccal and gill chamber pressures. Using phylogenetically corrected generalized least squares models (PGLS), I linked variation in pressures to morphology of the ventilatory pumps, and variation in pressures correlated closely with the size of the branchiostegal 3 apparatus. I propose that adding a third pump to the traditional two-pump model, in which the branchiostegal rays work in parallel with the operculum, is a useful framework for comparative gill ventilatory studies. In the fourth chapter, I reconstructed the phylogeny of sculpins and close relatives (Cottoidei) using published molecular data to analyze measurements of cranial bones from a subset of 23 cottoids. Using PGLS models, I found that suction-feeding associated characters (jaws and operculum) are closely evolutionarily correlated. However, there is only weak correlation between the branchiostegals and these structures. The branchiostegal apparatus may be a source of modularity within gill ventilation that releases constraints imposed by close coupling of feeding and ventilation. 4

Engineered Nanoparticles (NPs) have been widely used in various industrial processes and consumer products. While there seems to be unlimited potential that nanotechnology would improve the quality of our lives, it is inevitable that these manufactured materials will find their way to enter the environment. This study systematically studied the transport, retention and deposition of several industrially important metal and metal oxides NPs (CeO2, TiO2, ZnO and Ag) under different environmental conditions in the aquatic systems. The stability, transport and deposition of engineered CeO2 nanoparticles through water-saturated column packed with sand were studied by monitoring effluent CeO2 concentration. The influence of solution chemistry such as ionic strength (1–10 mM) and pH (3–9) on the mobility and deposition of CeO2 nanoparticles was investigated by using a three-phase (deposition-rinse-reentrainment) procedure in packed bed columns. The results show that water chemistry governs the transport and deposition of CeO2 nanoparticles. A mathematical model was developed based on advection-dispersion-adsorption equations and it successfully predicts the transport, deposition and re-entrainment of CeO2 nanoparticles through a packed bed. There is strong agreement between the deposition rate coefficients calculated from experimental data and predicted by the model. This study also studied the role of natural organic matter (NOM) in the transport and fate of NPs in the aquatic environments. Unlike other studies which used synthesized or standardized NOM samples, this study used NOM that was obtained from OhiO River, which has more practical relevance. The influence of this NOM on the surface charge, transport and retention of Ceria NPs was investigated in packed columns. Results indicated that the properties of Ohio River NOMs (OR-NOMs) differ from Suwannee River Humic Acid (SRHA), which is commonly used as standard NOM in similar researches. OR-NOMs showed a distinct effect in stabilizing and mobilizing CeO2, and the summer NOM had a higher stabilizing effect than winter NOM. The stabilizing effect is attributed to both electrostatic effect and steric effect.This study also characterized, experimentally and theoretically, the transport and retention of engineered NPs through slow sand filters at drinking water treatment plants (DWTPs) under realistic conditions. The transport of four commonly used NPs (ZnO, CeO2, TiO2, and Ag, with bare surfaces and coated with capping agents) through filter beds filled with three difference sand surfaces were investigated. The results have shown that capping agents have a determinant importance in the colloidal stability and transport of NPs through the different filter media. The effort of the biofilm was less significant. The data was used to build a mathematical model which was used to simulate the performance of a scale-up slow sand filter and the effects on filtration cycle of traditional sand filtration system used in DWTPs. Finally, the study took a further step to examined and compared industrially coated and lab-coated NPs in the biofilm coated porous media and confirmed that The role of steric repulsion between electrostatically stabilized NPs and biofilm is a prevalent force against NPs retention in saturated porous media.

The estimated risks of being impacted by oil spills in the coastal waters were used to improve the oil spill contingency plan of Thailand. Functional roles of local agencies are integrated into the plan. Intensive measures are suggested for the coastal provinces located in high-very high risk zones, whereas light and moderate measures are suggested for the coastal provinces located in low and moderate risk zones, respectively. The estimated percentage risks due to simulated oil slicks hitting the coast and/or important resources (PRoilspill) were used to guide the year-round water activities that should be carefully handled at a certain radius with a low-moderate PRoilspill, whereas they should be avoided at a certain radius with a high-very high PRoilspill. Important measures before, during, and post periods of an oil spill incident are suggested to prevent and monitor oil spill incidents and mitigate their impacts on the environment.

Aquatic macrophytes play a significant role in maintaining water quality and ecosystem health. They provide refuge for algae-consuming zooplankton, stabilize sediment, consume nutrients, and provide habitat for aquatic vertebrates. However, high densities of non-native invasive macrophytes can cause harm to the lake ecosystem. A healthy aquatic macrophyte community consists of a diversity of native taxa. Common carp, an invasive species, can disrupt native macrophyte communities. High densities of common carp uproot aquatic macrophytes and stir up sediments, encouraging a turbid water state and low density of macrophytes. Water clarity and aquatic macrophytes will likely increase after the removal of common carp. However, it can take several years for native macrophytes to return after a large-scale fish manipulation. There is also concern that non-native invasive macrophytes will quickly dominate the littoral zone after carp removal.I evaluated the response of the aquatic macrophyte community, between 2009 and 2012, after the large scale removal of common carp from Lake Susan, Carver County, MN (MN DNR DOW ID 10-001300). To assess plant frequency of occurrence, plant communities were assessed using a point intercept survey method in the spring and mid-summer. To quantify changes in plant biomass, approximately 40 random biomass samples were taken during each survey. To further understand response of Eurasian watermilfoil (Myriophyllum spicatum), a non-native invasive plant, milfoil herbivore surveys were also conducted throughout each summer. To evaluate recruitment potential of the non-native curlyleaf pondweed (Potamogeton crispus) turions were sampled each October. Comparisons of the plant community were done between the years to understand the succession of natural plant recruitment.To promote the recruitment of native plants, I transplanted six native taxa from nearby Lake Ann into Lake Susan to increase the species richness and distribution macrophytes within the lake. Four separate transplant experiments were conducted, each assessing a different variable. The primary focus of experiment one was to assess the survival of selected taxa and compare growth between open locations and those protected from herbivore access. The primary focus of experiment two was to increase the number of transplant locations geographically around the littoral zone, and correlate environmental growth factors (light, sediment bound nitrogen, sediment bulk density, sediment organic matter, and wave protection behind lily beds), to the expansion of the transplanted taxa. Experiment three tested transplant survival and expansion at greater depths. Experiment four evaluated if earlier planting of transplants improved survival of deeper transplants.There was an increase in the diversity and overall abundance of submersed aquatic macrophytes in Lake Susan after common carp population was reduced. Species richness increased naturally from 13 taxa in 2009 to 14 in 2012. The number of sites with moderate diversity (>4 taxa per site) increased from 8 sites to 2009 to 12 sites in 2012. There was also an increase in the frequency of occurrence of most taxa. Total dry shoot biomass of both native and invasive taxa also showed a statistically significant increase (p

Nanomaterials (NMs) have promised lighter, stronger, smaller and more efficient products in areas such as electronics, medicines and even environmental sectors. This investigation started at the base of the food chain and characterized NMs interactions with aquatic plants. Citrate capped gold nanoparticles were used as a model nanoparticle to track fate and gain insight on factors that influence gold nanoparticle (AuNP) bioavailability and absorption. Four species of aquatic macrophytes were investigated. Azolla caroliniana, Myriophyllum simulans, Egeria densa and Myriophyllum aquaticum were selected due to growth habitat, leaf morphology and root structure. Because aquatic plants absorb the majority of their nutrients from the water column, it is logical to hypothesize that they may absorb nanomaterials in suspension, potentially facilitating trophic transfer. Azolla caroliniana, E. densa and M. simulans were exposed to 4 nm and 18 nm AuNPs at a nominal concentration of 250 μg Au/L for 24 h. Macrophytes were harvested at six different time points (1,3,6,12,18 and 24 h), dried and then analyzed for gold concentration via inductively coupled plasma mass spectrometry. Concentrations were normalized to whole plant dry tissue mass. Electron microscopy revealed that 4 nm and 18 nm AuNPs adsorbed to the roots of each species. Further, it was observed that 4 nm and 18 nm AuNPs were absorbed by A. caroliniana, however, only 4 nm AuNPs were absorbed by M. simulans; E. densa did not absorb AuNPs of either size. To further identify factors that influence the bioavailability of gold nanoparticles to aquatic macrophytes, A. caroliniana, E. densa and M. simulans were exposed to 4, 18, and 30 nm gold nanoparticles. Results indicated that particle uptake was influenced by plant species, presence or absence of plant roots, particle size and dissolved organic carbon and their interactions; this suggests that nanoparticle bioavailability is influenced by multiple parameters. Absorption of AuNP was species specific and dependent upon the presence of roots and nanoparticle size. In the presence of dissolved organic carbon, the suspension of 4 and 18 nm gold nanoparticles formed a nanoparticle/organic matter association that resulted in 1) minimized particle aggregation and 2) a decrease of nanoparticle absorption by the aquatic plants. The same effect was not observed with the 30 nm nanoparticle treatment. Multiple factors, both biotic and abiotic, must be taken into account when predicting bioavailability of nanomaterials to aquatic plants. Electron microscopy was used to further investigate the influence of AuNP size on species dependent uptake. Root micrographs of E. densa, M. simulans and A. caroliniana indicated that absorption of gold nanoparticles from suspension correlated with root microfibril density. The microfibril network defines the porous structure of the root cell wall. The cell wall porosity of A. caroliniana was 4.5 - 5.0 nm, as measured by solute exclusion. The effect of evapotranspiration on AuNP uptake was measured over 16 days for emergent species A. caroliniana and M. aquaticum using 4 nm AuNPs. Disrupting boundary layers and varying humidity around the emergent plant achieved changes in the evapotranspiration rate. Placing plant units under a fan, in a sealed system or open (control) conditions correlated with increased, decreased or control measured evapotranspiration rates. Plant root and shoot samples were separated and analyzed for gold content. Increased evapotranspiration rates correlated with an increase in AuNP root loading (mg Au/kg dry tissue/24 h). An average of 18.83 ± 3.3 mg Au/kg dry tissue/24 h was observed in the fan treatment for A. caroliniana and in M. aquaticum, an increase of 1.07 ± 0.18 mg Au/kg dry tissue/24 h was observed in the fan treatment when compared to the control treatments. While an increase in evapotranspiration rate increased root loading, shoot concentrations of Au did not correlate with evapotranspiration rate. This suggested that shoot translocation was a diffusive process, not dependent on water movement into the root tissue. Shoot tissue concentrations in A. caroliniana increased from 14.58 ± 3.29 mg Au/kg dry tissue to 140.15 ± 6.73 mg Au/kg dry tissue over the course of 16 days. This corresponded with an average AuNP translocation rate of 6.79 ± 3.26 mg Au/kg dry tissue/24 h in A. caroliniana. At the same point, day 16, root tissue concentration for A. caroliniana is the highest observed, 1265.34 ± 139.3 mg Au/kg dry tissue. Overall, my dissertation results indicate that absorption of gold nanoparticles by aquatic macrophytes from suspension is a complex interaction of plant species, nanomaterial size, levels of dissolved carbon in water, root structure, and evapotranspiration rate. Because no visual toxicity or deleterious effects were observed with the exposure of AuNPs to aquatic plants, there is potential for the use of AuNPs in tracking and fate studies within these macrophytes.

While environmental controllers of decomposition have been extensively studied, organic matter quality and biotic controllers of decomposition, such as detritivore preference and manipulation of detritus, are largely understudied. In the studies described in this dissertation, a range of biotic controllers of detrital dynamics in aquatic ecosystems are presented. Crayfish, as model shredders, produce a diverse pool of fine particulate organic matter (FPOM) through fragmentation of coarse particulate organic matter (CPOM) and fecal production in the laboratory. Crayfish process maple leaves at a greater rate than oak leaves, and produced a greater amount of FPOM from maple compared to oak. Crayfish-generated FPOM had lower C:N ratios and increased bacterial abundances compared to original CPOM. Further, hydropsychid caddisfly and simuliid blackfly larvae confer greater growth efficiency when reared on crayfish-generated FPOM compared to mechanically ground FPOM in the laboratory, indicating that crayfish increase bioavailability of FPOM. No differences in growth or metamorphosis of simuliid larvae were observed when larvae were lab-reared on crayfish-generated FPOM from CPOM of different tree species (i.e., sugar maple, sycamore, or white oak) or different stream conditioning times (i.e., 30 or 150 d). This suggests that crayfish processing reduces organic matter origin effects on bioavailability. Changes in macrophyte abundance in a tropical wetland due to competition and ecosystem management can affect litter availability and litter quality. In two field-based, replacement series experiments with floating-mat macrophytes (Eichhornia crassipes and Neptunia oleracea), no interspecific competition was detected. However, E. crassipes dominated experimental enclosure biomass through attrition. Decomposition rates were faster for E. crassipes litter compared to N. oleracea litter within enclosures, but no differences in decomposition rates were detected by floating-mat species composition. Both synergistic and antagonistic diversity effects were observed on decomposition dynamics in an experiment varying litter richness from one to five species. Additionally, cattail (Typha domingensis) eradication efforts lead to changes in the decomposition landscape within the wetland, as E. crassipes colonizes managed areas, and decomposition rates were slower for litter of T. domingensis compared to E. crassipes. The compounding effects of litter species, detritivore interactions, and anthropogenic impacts on organic matter dynamics illustrate that it is critical to consider ecosystem function in ecosystem management.

The global decline in freshwater ecosystem health has prompted governments to return water to rivers to restore natural flow regimes. Adequate volume, temporal variability and spatial connectivity of flows are essential requirements for maintaining freshwater ecosystem integrity. However, a major challenge is integrating environmental flow requirements into regulated river systems historically managed for water supply and flood mitigation. In my thesis, I aimed to: (1) evaluate operational opportunities and challenges for the allocation, release and delivery of environmental flow in regulated rivers; and (2) support environmental flow management capacity building through decision support tools and techniques. I focused on two inland river systems in Australia's Murray-Darling Basin, the Gwydir River and the Macquarie River, where unprecedented environmental water investment aims to rehabilitate degraded semi-arid floodplain wetlands of international significance: the Gwydir wetlands and the Macquarie Marshes. Chapter 1 provides an overview of the global importance, progress and challenges of integrating environmental flows into regulated rivers. Chapter 2 outlines the development and application of a long term daily decision support tool for explicit simulation of environmental water allocation and flexible specification of water management rules. Chapter 3 demonstrates the importance of management and biophysical factors in influencing long term availability of environmental water. Chapter 4 examines operational implications of different environmental water release strategies, illustrating the need to include operational opportunities and risks together with ecological outcomes in a strategic environmental watering planning framework. Chapter 5 examines techniques for efficiently and effectively identifying floodplain earthworks built for irrigation and flood mitigation which often fragment spatial flow connectivity and interrupt delivery of environmental flows to target floodplain assets. Results demonstrated that semi-automated Geographic Information Systems techniques were an effective and efficient alternative for large scale earthwork detection compared to traditional visual interpretation. Chapter 6 synthesizes the research presented in my thesis and suggests directions for future research towards a transparent, systematic and adaptive approach to decision making in river systems progressing towards sustainable integrated water resource management.

The intent of this research was to investigate the effects of fluid flow characteristics and epiphyte colonization on submerged aquatic vegetation (SAV) photosynthesis and dissolved material uptake. SAV, with its stems and leaves completely submerged in the water column, is strongly affected by both the physical characteristics of the water, such as dissolved material concentrations and fluid motion, and by factors that alter its interaction with the water, such as epiphyte colonization of SAV surfaces. The nature of these interactions was investigated through a series of four separate studies. First, through a laboratory mesocosm experiment, epiphyte uptake and SAV uptake of a dissolved contaminant (nickel) were shown to occur at different rates and due to different mechanisms. Second, a model of photosynthetic rates, based on mass transfer theory, was developed requiring only three parameters that accounted for the effect of water motion on photosynthetic rates. This model was experimentally validated with dissolved oxygen and velocity profiles over blades of giant kelp, Macrocystis pyrifera. Third, using two separate microscale velocity imaging methods, photosynthesis was shown to alter fluid motion near the surface of a Cladophora spp. filament by more than doubling velocity gradients and thus surface shear stress. In this investigation, bacterial epiphytes had no effect on shear stresses but assemblages consisting primarily of diatom epiphytes strongly decreased the surface shear stress from what would have been experienced during photosynthesis without epiphytes present; indicating a harmful interaction with epiphytes. Fourth, in agreement with the microscale results in the third study, epiphyte removal was shown to increase local dissolved oxygen concentrations throughout the water column as well as decrease water column soluble reactive phosphorus concentrations due to higher photosynthetic rates in field research in a constructed wetland. In a related laboratory study, epiphyte detachment rates were functionally related to water velocity. Overall, I have shown through laboratory and field experiments that SAV photosynthesis is closely linked to fluid flow characteristics, SAV and epiphyte uptake are not equally affected by flow conditions, and epiphyte colonization decreases SAV photosynthetic rates.

SourceURL:file://localhost/Users/johnmoulton/Desktop/SenatoreGailMay2012.docA molecular approach was taken to differentiate morphologically homogeneous species within the Simulium jenningsi species group (SJG). This group of Nearctic black flies consisting of 22 recognized species has its highest diversity in the southeastern United States. No other group of black flies in this region is more ubiquitous or pestiferous. Female black flies in this group are nearly isomorphic, which complicates identification, elucidation of host specificity and pest status, and directed control of through application of Bti in the appropriate natal streams. Among SJG species, only S. luggeri Nicholson & Mickel, S. jenningsi Malloch, and S. penobscotense Snoddy & Bauer have well documented medical and veterinary importance. However, in the Deep South these three species are uncommon or not present (penobscotense), so other group species must be to blame for causing human discomfort. The objective of this study was to use sequences from the nuclear gene speckle (IKappaB kinase complex) for identification of and phylogenetic resolution among SJG species. The ultimate application of the fruits of this project is enabling the identification of pest females. Several positively identified individuals (mostly pupae) of each species were used as standards against which unknowns can eventually be compared. Parsimony and Bayesian phylogenetic analyses were conducted. The data obtained permitted identification of all morphospecies except S. nyssa Stone & Snoddy, S. infenestrum Moulton & Adler, and S. penobscotense. It could not resolve relationships within the fibrinflatum (fibrinflatum Twinn, notiale Stone & Snoddy, snowi Stone & Snoddy, and underhilli Stone & Snoddy) and taxodium (taxodium Snoddy, lakei Snoddy, chlorum Moulton & Adler, confusum Moulton & Adler) complexes. A large degree of polymorphism was observed within several species, possibly indicative of introgression or highly polymorphic antecedent species.

In recent decades, Western Basin of Lake Erie has been beset by various episodes of dense and sometimes harmful algal blooms. The federal government has mandated that jurisdictions have plans in place to predict and respond to harmful algal concentration explosions. In very large lakes like Lake Erie, satellite remote sensing can provide synoptic glimpses of the dynamics of algal growth along with wind and current mixing patterns. Colored dissolved organic matter (CDOM), which is a component of the water, absorbs light strongly in the ultraviolet to blue wavelengths, which overlaps a strong absorption area of the spectrum for the chlorophyll a in algae. Measurements in these wavelengths are essential for remote quantification of chlorophyll a aquatic concentrations. Since CDOM only absorbs electromagnetic energy and does not reflect a signal to the satellite, the purpose this study is to characterize the variation in the absorption spectrum of CDOM temporally and spatially in the Western Basin, detect terrestrial influences on the spectral slope of absorption, S, and determine the effect of S variations on satellite retrieval algorithms.In 2011, absorption spectra for over 100 Western Basin water samples were measured with a spectrophotometer, and S, was calculated for each sample. The spectral slope values were tested for correlation with contemporaneous water physical factors and meteorological conditions. Changes in slope were compared to the timing of hydrograph peaks of four tributaries to the Western Basin. Using SeaDAS processed MERIS scenes from dates near the dates of the collections, slope values were examined as to their spatial relationships with algal blooms in the basin. To test the effect of the S variations on the results of satellite chlorophyll algorithms, the results of various values of CDOM and other optical components were modeled with HydroLight software. The remote sensing reflectances output by the model were applied to the OC3 algorithm to see what satellite retrievals would return compared to in situ chlorophyll concentrations.No strong relationships between CDOM spectral slopes and the other parameters tested were verified during this study. The Western Basin is shallow, has a rapid rate of water column turnover, and steady currents moving the water masses. The results of large scale mixing may have made it difficult to track water masses with different CDOM absorption spectra. The slopes measured for the CDOM over the 2011 season ranged from 0.004 to 0.042 which is a broader variability than had been previously published for Lake Erie. The mean S was comparable to published data. CDOM S values of 16 and 11 produced the best performance of satellite-band retrieved values in the chlorophyll a algorithm, but often that meant errors of 30 or 40 percent.

An invasive insect, hemlock woolly adelgid (HWA), has initiated widespread hemlock decline and mortality in the Great Smoky Mountains National Park (GSMNP). Riparian hemlock mortality impacts on vegetative and aquatic systems of first-order, headwater streams were evaluated. Reference sites for this study were representative of the best available conditions within the GSMNP, with initial stages of HWA presence. Impacted sites were defined as areas with over 90 percent hemlock mortality. Impacted streams had decreased canopy coverage and increased light availability. Residual red maple, yellow birch, and sweet birch capitalized on the loss of hemlock, with increases in relative basal area and species importance values. Rosebay rhododendron responded with increased density and height at impacted sites, thereby preventing woody regeneration. Since long-term regeneration and post-mortality canopy recruitment are limited, alterations of vegetative composition and structure in the stream riparian zone are expected. A seasonal assessment (Sept. 2009 – March 2010) of aquatic impacts revealed increased diurnal variation in stream temperature and exhibited cooler temperatures during the colder months than reference streams. Impacted streams exhibited greater amounts and larger size classes of large woody debris (LWD). Higher concentrations for several nutrients, including silicon, sodium, potassium, magnesium, chlorine, and copper were detected in impacted streams than detected in reference streams. Impacted streams were characterized by higher pH and increased acid neutralization capacity, while reference streams exhibited nitrate concentrations three times higher than impacted stream concentrations. Reference streams were experiencing the initial stage of HWA-induced defoliations, increasing stream nitrate concentrations, while impacted sites had levels suggesting nitrate concentrations have returned to pre-infestation levels. A seasonal assessment of macroinvertebrates found species diversity, abundance, and taxa richness were not affected by hemlock mortality. Impacted streams had a lower density of Chironomidae and Ephemeroptera when compared to reference streams, while Pleuroceridae snails were virtually eliminated at impacted stream sites. Reference streams were dominated by the collector/filter functional feeding group (FFG), while impacted streams were dominated by the scraper FFG. Hemlock mortality induced by the presence of HWA has resulted in short-term impacts to vegetative and aquatic dynamics in stream riparian areas of the Great Smoky Mountain National Park.

The field of viral ecology is still relatively new and many processes by which viruses influence hosts are still widely unknown. One problem is that there are few standardized techniques in virus ecology, making comparisons of data very difficult. To better understand the methodology, we first set out to make a video showing the process for the viral production assay using the “dilution and reoccurrence” method, which has become the standard to analyze production rates in aquatic ecosystems. Using this method, we also determined the production rates of viruses during a seasonal pelagic phytoplankton bloom during a cruise off the coast of the north island of New Zealand in the subtropical Pacific Ocean. Other biotic and abiotic parameters were also compared throughout the bloom. Production rates were within normal ranges, but showed that viruses were very important for the remobilization of nutrients in the nitrogen-limited system. It is well known that the cyanobacterial genera Synechococcus and Prochlorococcus thrive in the world’s oceans with Synechococcus and other cyanobacterial species also succeeding in freshwater ecosystems. Cyanophages are viruses which infect cyanobacteria and many studies have investigated their diversity using the portal vertex g20 gene in the Cyanomyoviridae family. Although we know that there is significant genetic richness in these phage in marine and freshwater environments, information on their numerical distributions is rare. Using quantitative PCR with the g20 gene, we determined that cyanomyoviruses are ubiquitous and abundant in the Atlantic and Pacific Oceans as well as within Lake Erie. Using statistical analyses we were able to find correlations between cyanomyoviruses and other biotic and abiotic parameters: in the Sargasso Sea, cyanomyovirus abundance correlated well to biology, but in the other systems there was no significant correlation to biological abundances. This suggests that the constraints of this group of viruses may be different in different aquatic realms.

In cities across America, there are various existing assets that were produced to complement the overall system making up total infrastructure. Often, however, rather than utilizing existing forms of transportation infrastructure (e.g. unused rail lines, navigable water), new highways and roads are built to serve areas that can already access existing non-road assets. Better use could be made of existing, viable infrastructure for a lower cost than new highway construction, while leaving far greater areas of land open for development. This would result in significant economic, social, and ecological spillover benefits. The use of such infrastructure for mass transit would provide declining communities with decreased travel times to other places, such as central business districts, since they would provide dedicated rights-of-way. Often, waterside communities are filled with properties that are not economically feasible to develop due to high costs in elevating them above floodplains. A relatively small investment in aquatic-based transit, such as vessels and dock improvements but little property acquisition or right-of-way construction and maintenance, would immediately make these properties worth reclaiming, promoting the infill redevelopment of existing communities rather than furthering detrimental urban sprawl.

Globally, natural wetlands are under threat from water resource development reflecting the need to support a growing population. In the Border Rivers Catchment in Queensland, Australia, a large irrigation industry coupled with a highly variable flow regime has necessitated the building of large on-farm water storages and often associated destruction or isolation of their natural counterparts. With the decline in abundance of natural wetlands, the presence of these storages on the floodplain has raised the question of their suitability as alternative aquatic habitat. This project aimed to investigate the diversity of storages and the structure and function of the aquatic assemblages they support compared with nearby natural wetlands. These results were then used to recommend best management practice for optimising both diversity and ecosystem function in storages. Initially the physical variety of water storages in the Border Rivers Catchment was described and their morphology and hydrology compared to that of natural wetlands. Storages and natural wetlands formed two distinct groups based on morphology. Storages tended to be large, deep structures with a more regular shape, while natural wetlands were irregular and shallow with large perimeters. Although there was a degree of variability amongst storage sites, most fell into one group and were considered to be a ‘typical’ storage in this region. After classifying the storages based on hydrology and morphology, the spatial and temporal biodiversity of the different storage groups was compared with natural wetlands. Spatial patterns (between waterbody types) in fish and macroinvertebrate assemblages composition were explored between August and October 2005 in three waterbody types; natural wetlands, typical storages and a group of storages with similar morphology to typical storages but lacking tailwater (‘no tailwater’ storages). In total nine fish species were collected comprising seven natives and two exotic species. Only one species, the eel-tailed catfish, Tandanus tandanus, was specific to natural wetlands. Although fish species diversity was similar between the two storage types and natural wetlands, there was significant spatial variation in total abundances, with typical storages having ten times the average catch size of that found in natural wetlands. In both storage types catches were dominated by bony bream, Nematalosa erebi, while in natural wetlands there was a more even distribution of species. The percentage of exotic species was much lower in both storage types (< 8%) compared with natural wetlands (> 40%). There were also significant spatial differences in macroinvertebrate assemblages; 24 samples from natural wetlands were represented by more than 14,500 individuals across 84 different taxa. In comparison, only 34 taxa from 2,142 individuals and 34 taxa from 7,611 individuals were collected in 15 samples from typical storage sites and 12 samples from ‘no tailwater’ sites respectively. Seventeen taxa were common to all three waterbody types while 45 taxa were specific to natural wetlands. None of the measured environmental variables explained the observed variation in macroinvertebrate assemblages between waterbody types. Temporal patterns in macroinvertebrate and zooplankton assemblages were also investigated comparing natural wetlands and typical storages during the 05/06 and 06/07 cotton seasons. Specifically, macroinvertebrate and zooplankton assemblages from typical storages were less diverse than those found in natural wetlands. Temporal variation in aquatic assemblages was also apparent with macroinvertebrate and zooplankton assemblages of both waterbody types following a similar pattern through time. However, there were no strong associations between the environmental data collected and the observed assemblage composition. To further investigate the spatial variation observed in aquatic assemblages, two sources of colonisation of storages were examined, namely the aquatic assemblages found in extracted river water and those hatching from the egg bank. Eight different fish species including three exotics were collected during sampling of pumped river water. As was observed in storages, the catch was dominated by N. erebi and the contribution of exotic species to the total catch was extremely low (< 1%). Fish with a standard length of over 200 mm survived the extraction process. The eight samples of pumped river water were represented by 22 macroinvertebrate taxa and 332 individuals. This was a reduced diversity than collected from typical storages (34 taxa). In comparison, zooplankton assemblages had similar diversity to those observed in the typical storages, 25 taxa compared with 22 taxa. Sediment samples collected from the floodplain had a more diverse but less abundant egg bank (46,463 individuals from 20 taxa) than those collected from dry typical storages (70,600 individuals from 16 taxa). The observed spatial differences in morphological and hydrological features and aquatic assemblages suggested that there may also have been variations in aquatic processes between waterbody types. Stable isotope analyses were used to investigate the major sources of energy fuelling the aquatic food webs of natural wetlands and typical storages. In general all components of the food web in typical storages were 13C and 15N-enriched in comparison with natural wetlands. The importance of source carbon to consumers varied greatly between species, sites, and waterbody types. Algae, in the form of biofilm and floating algae, along with zooplankton were the major sources of organic carbon to aquatic food webs, contributing 50% of organic carbon across natural wetlands and 54% across typical storages. Storages primarily function as water supplies and their associated management makes them mostly unsuitable as ‘replacement’ wetlands. However, given the large numbers of storages across the catchment, if managed effectively, they may provide an additional source of aquatic habitat and help maintain regional biodiversity. To maximise the biodiversity of storages it will be essential to reduce the morphological homogeneity of storages across the landscape and increase habitat diversity within storages. In the future, improved design of new storages and alterations to existing storages and their management could help overcome this problem of low diversity of habitat. As a group, storages in the Border Rivers Catchment are still fundamentally different to natural waterbodies, with storages being a mostly homogeneous group. If we are to sustain the aquatic biodiversity in the Border Rivers Catchment and other similar irrigation regions it will be necessary to preserve the spatial and temporal variation in habitat evident in natural wetlands.

Freshwater mussels (Family Unionidae) are one of the most imperiled groups of animals in North America with approximately 75% of the currently recognized species listed by federal or states as endangered, threatened or species of concern. Despite this designation, conservation of freshwater mussels has been extremely difficult being limited by an inadequate knowledge of even the most basic principles of biology (e.g. life history, reproductive biology, ecology, habitat requirements, etc). Two of these that continue to pose challenges to the conservation of this important group of animals include; identification of 1) taxonomic units appropriate for conservation, and 2) criteria useful for the establishment or re-establishment of populations of freshwater mussels that are endangered, threatened, or species of concern. To address issues associated with the identification of freshwater mussels we employed a modern phylogenetic approach using an enigmatic and important group of unionids (Villosa) in order to assess ambiguities in taxonomic position and delineate species boundaries. We used nucleotide sequences of the cytochrome oxidase I subunit (COI) and NADH dehydrogenase I (NDI) subunit of the mitochondrial DNA (mtDNA) genome to infer taxonomic boundaries and to provide a more relevant phylogenetic framework within the Unionidae. We also used a nearly panmictic species, Villosa iris, to address patterns of speciation associated with observed morphological variation in a small river taxon which also allowed us to evaluate existing hypotheses regarding the evolution of drainage basins of the eastern U.S. Lastly, we provide a set of criteria that should be addressed for conservation activities associated with the relocation, translocation, and reintroduction of freshwater mussels.Our assessment of Villosa iris revealed multiple cryptic species across the range of this taxon that correlate with vicariant events associated with the evolution of major drainages throughout the eastern U.S. (Chapter 2). Our phylogenetic studies also revealed a polyphyletic Villosa comprised of at least 9 clades that include species from five different genera (Chapter 3). These studies indicate 1) that current systematics for Villosa is largely inadequate, 2) morphological (conchological) characters used to diagnose taxonomic boundaries within the Villosa in most instances are not useful, 3) a modern phylogenetic approach is necessary for accurate identification of evolutionary lineages within unionids, 4) modern phylogenetic methods will aid in implementing appropriate conservation strategies.Finally, using two federally endangered freshwater mussels, Pleurobema clava and Epioblasma torulosa rangiana; we provide a framework for evaluating potential sites for relocation, translocation, and reintroduction in two Ohio watersheds. This framework includes a discussion of past and current threats, conservation activities, and identifies biological and physical criteria that can be used to evaluate potential sites for conservation activities.

This research investigates the mechanism for reproductive and developmental toxicity associated with the aquatic contaminants nitrate and nitrite, in the crustacean Daphnia magna. Two hypotheses were tested: 1) Nitrate and nitrite are converted to nitric oxide(NO), resulting in disruption of endocrine-related processes; and 2) NO interferes with endocrine signaling by lowering steroid hormone levels or by binding a heme-containing nuclear receptor involved in steroid signaling. In the first study, the developmental and reproductive toxicity of nitrate and nitrite to daphnids was consistent with toxicity elicited by the NO donor, sodium nitroprusside and was ameliorated by the NO-scavenger ß-carotene. Drosophila S2 cells converted nitrate and nitrite to NO in a substrate and cell concentration-dependent manner. Together, these results are consistent with nitrate and nitrite eliciting toxicity via intracellular conversion to NO. Although toxicity was indicative of an anti-ecdysteroid mechanism of action, we did not detect significant, consistent decreases in 20-hydroxyecdysone levels in exposed daphnids. The next study characterized a potential target of NO toxicity in the ecdysteroid signaling pathway. The nuclear receptors E75 (group NR1D) and HR3 (NR1F) were cloned and sequenced from Daphnia magna. E75 possessed amino acid residues in the ligand-binding domain that likely bind heme, a common target of NO binding. HR3 was significantly induced by 20-hydroxyecdysone, whereas E75 was minimally responsive. These results implicate both E75 and HR3 of daphnids as potential targets of the anti-ecdysteroid action of exogenous NO. Finally, we characterized E75 and HR3 regulation of gene transcription, to determine if NO alters this regulatory activity. HR3 activated transcription of a retinoid orphan receptor element (RORE)-driven luciferase reporter. E75 did not activate the reporter, but served to repress HR3 activation. Experiments revealed no evidence that NO interferes with E75 repression of HR3. Therefore, the mechanism by which nitrate and nitrite-derived NO elicits developmental and reproductive toxicity remains unknown. This research highlights the potential threat posed to the reproductive and developmental success of aquatic organisms exposed to nitrate and nitrite. It additionally advances understanding of crustacean endocrinology, while demonstrating the need for further information to identify the mechanism of action for interfering environmental contaminants.

I investigated life history traits and secondary production of populations of Goniobasis proxima in four streams from July 2005 to June 2006. Measurements of canopy cover, conductivity, alkalinity, temperature, and nitrate-nitrogen (NO3-N), as well as snail size, density, and occupied substrate were taken monthly for each stream. Snail growth rates were determined in an aquarium for 10 size classes and secondary production was estimated as the summed product of size class growth rates and field biomass measurements. Size class production estimates tracked biomass with intermediate to larger sized snails dominating production, despite smaller snails growing faster. Production estimates across streams ranged from 1,400 mg m-2 yr-1 to 22,183 mg m-2 yr-1 with noticeable summer highs and winter lows. Annual turnover was slow (0.43-0.49) owing to slow growth and long development time. Snails preferred leaves/wood as a substrate to occupy over rock and sand and showed no appreciable grazing effect on the epilithon community.

Amphibians represent an important aspect of wetland ecosystems. Since the 1990’s, many herpetologists have supported the idea that amphibian population declines have become more frequent. Destruction and degradation of aquatic and terrestrial habitat have been implicated as important causes of amphibian population declines. While many amphibian species rely on both aquatic and surrounding terrestrial habitat for continued persistence, current regulations often provide an inadequate degree of protection in these terrestrial areas. Some states have adopted limited buffer zones to offer additional protection to these important terrestrial regions. The major goal of this study was to determine if the distribution and abundance of aquatic breeding amphibians within the Cuyahoga Valley National Park is related to various surrounding habitat and water quality characteristics. The results of the current study indicate that certain species may be more strongly impacted by land-use in areas most directly adjacent to aquatic breeding sites.

Invasive plant species are increasing worldwide and often have significant impacts on local ecosystems. Many attempts have been made to use augmented herbivore populations as a biological control of nuisance populations, however, the success of these efforts has been variable. One character which can affect the success of these biological controls is the expression of plant herbivore resistance. In this study I examined inducible and constitutive herbivore resistance in native and invasive samples of the aquatic angiosperms, Myriophyllum spicatum and Myriophyllum heterophyllum. M. spicatum is native in Europe, Asia and north Africa and invasive in much of North America. When fed on by the ecologically significant herbivore, Acentria ephemerella, M. spicatum plant tips changed from green to red with a simultaneous structural change from closed upward pointing leaves to open drooping leaves. A similar response was observed in this study when native and invasive M. spicatum plant tips were exposed to jasmonic acid, a plant hormone known to stimulate the expression of plant defensive genes. A. ephemerella fed plant tips exposed to jasmonic acid had reduced growth compared to individuals fed unexposed plant tips indicating the induction of herbivore resistance. Not all of the herbivore resistant traits we examined, however, were induced by jasmonic acid. Total phenolics and tellimagrandin II concentrations were not affected by jasmonic acid and changes in nitrogen concentrations were inconsistent. Tissue reddening, in part caused by decreased chlorophyll and increased anthocyanin concentrations, was consistently induced and may affect the visibility of herbivores in the field. However, this trait can not explain the reduced herbivore growth so it is likely that other herbivore-resistant traits, not examined in this study, were induced in M. spicatum. M. heterophyllum is native to North America (except New England) and has invaded many New England and European lake ecosystems. When exposed to jasmonic acid in this study, concentrations of total phenolics, and an unknown phenolic compound were increased and nitrogen concentrations were decreased. These induced plant tips reduced the growth of feeding A. ephemerella. This response, however, was only observed in German (invasive) M. heterophyllum and not in samples from Maine (invasive) or New York (native). The constitutive expression of traits presumed to confer herbivore resistance was also significantly different among invasive and native populations. Maine had significantly higher concentrations of total phenolics and the unknown phenolic was only present in German M. heterophyllum. These differences in constitutive and inducible herbivore resistance among native and invasive M. heterophyllum populations may be a result of rapid evolution of invasive populations or their hybridization with native Myriophyllum species. The constitutive and inducible herbivore resistance of M. spicatum and M. heterophyllum shown in this study would have a negative impact on biological control species which has not previously been considered by lake managers. Furthermore, differences in the expression of herbivore resistance among invasive and native populations of M. heterophyllum may partially explain the variable success of this invasive species.

An increase in public environmental awareness and a decrease in resources within government regulatory agencies have led to a larger interest in volunteer biomonitoring programs. Government agencies are currently using volunteer data for official purposes with increasing frequency, but questions have been raised about the validity of the data collected by volunteers who have only limited training and experience. Therefore, we conducted a detailed study to assess, modify, and validate the Virginia Save-Our-Streams (SOS) program, which is a volunteer organization collecting macroinvertebrate data. Sites were sampled using professional methods concurrently with volunteers who utilized the SOS protocol. The volunteer samples were retained for further laboratory analysis. In addition, numerous sites previously sampled by volunteers were re-sampled using professional methods. The data were statistically analyzed to determine if the results of volunteers and professional aquatic biologists were correlated and if they arrived at the same conclusions about ecological condition. It was determined that the Virginia SOS method, and probably other similar volunteer methods, consistently overrate ecological condition. This means that streams impaired by pollution could go unreported, if they are monitored exclusively by volunteers. The cause of this overestimation was determined to be the overly simplistic SOS metric, which is based solely on the presence or absence of taxa. The SOS protocol for data analysis was made more quantitative by developing a multimetric index that is appropriate for use by volunteers. The SOS sampling protocol was modified slightly to obtain actual counts of the different kinds of macroinvertebrates, which allowed for calculation of metrics. Sorting effort and taxonomic level of identification were not changed so that currently participating volunteers would not be excluded because of the need for expensive equipment or advanced technical training. The modified SOS protocol was evaluated by a different set of concurrent samples taken by volunteers and professionals, but using the same statistical techniques. The modified SOS protocol proved to be feasible for volunteers. The new SOS multimetric index correlated well with a professional multimetric index. The conclusions about ecological condition derived from the volunteer multimetric index agreed very closely with those made by professional aquatic biologists. This study demonstrated that volunteer biomonitoring programs can provide reliable data, but every volunteer program needs to be thoroughly validated by statistical comparisons to the professional methods being used in that area.

TD-55 A Thesis presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Forestry, Fisheries and Wildlife, Under the Supervision of Professor Edward J. Peters. Lincoln, Nebraska: May, 1987. Copyright (c) 1987 Laurence Angle

This study investigated the effects of ungulate herbivory, principally of elk and moose, upon riparian and stream ecosystems within the Greater Yellowstone Ecosystem. The emphasis of the research concerned whether these effects express themselves within the aquatic macroinvertebrate community. The research design entailed the identification of several streams that were selected as suitable sites according to criteria established prior to the study. Three general browsing categories, each comprising three to four streams, were used to distinguish intensities of herbivory among the sites; minimal herbivore use (control), moderate herbivore use, and heavy herbivore use. Within each site, five aquatic macroinvertebrates samples were collected from riffle areas with a Hess sampler. The organisms were identified to the lowest practicable taxonomic level and assigned to trophic groups upon the basis of gut content analysis. Riparian and in-stream variables also were measured. Statistical analyses were performed to elicit any significant differences in riparian, stream, and insect community indices among the streams and to relate the structure (i.e., diversity, trophic organization) of the insect assemblage to the riparian and stream variables. The analysis of the data yielded no statistically significant differences among the browsing categories with respect to embeddedness, bank overhang, and several physicochemical indices of water quality. Similarly, macroinvertebrate densities, biomass, and species richness did not differ among the categories. The trophic group analysis, however, revealed that the abundance and biomass indices of the scraper community were significantly greater within the heavily browsed sites than within the other streams. Conversely, the indices of the shredder community were significantly higher within the minimally browsed streams than within the other sites. It is proposed that the reduction of riparian vegetation incurred by herbivory and the attendant shift from allochthonous to autochthonous food resources accounted for these observations. Of critical importance is the fact that the shredders were not excluded from or even reduced in abundance within the heavily browsed streams, but rather seemed to have adapted to the decline in allochthonous matter by shifting their mode of food acquisition from shredding to gathering. The implications of such trophic generalism for understanding the structure and function of aquatic macroinvertebrate communities are discussed.

Aquatic toxicity tests are a unique tool for the evaluation of the toxicity of various environmental toxicants. However, they have many inherent problems and are costly. To improve the accuracy and reliability of long-term continuous-flow experiments, a system utilizing a microcomputer was developed. The monitoring of the test system was focused at two locations: (1) at the inflow section of a Benoit type dilution system, and (2) at the effluent side of the tanks where several water quality parameters measured at desired intervals. Several acute continuous-flow tests were run to determine the reliability of the computer integrated monitoring system. The concept of a tracer dye which would measure indirectly toxicant concentration was also evaluated. Each of the four 2-week long continuous-flow tests resulted in good quality data. Even though physical problems arose in this system, the experiments were completed without a restart. Early detection by the monitoring system resulted in the immediate resolution of the problem by the researcher. Rhodamine WT dye was used as surrogate for the toxicant diquat, which proved to be very efficient and reliable. With the employment of a mixture of diquat and dye, the diquat concentration was determined quickly in each exposure chamber. This was accomplished by analysing for the dye in the effluent fluorometrically which minimized the chemical analysis for diquat. The system developed is very economical and reduces the needed manpower for analysis by a factor of 5. It is more reliable and assures test runs over long periods of time having less breakdown and enhancing collection of good data. In the analysis of the results, a new statistical procedure for pooling the data from several tests was developed. This grand probit line procedure was based on the maximum likelihood probit method and comparative probit analysis. Computer programs written in BASIC for an IBM PC allowed the estimation of the time-dependent LC (50) values and the mapping of 3-dimensional dose-time-response surface from the long-term test data.