Abstract In this thesis, I used the Chironomid Pupal Exuvial Technique (CPET) to detect anthropogenic impacts and to determine chironomid species composition in boreal rivers and lakes. The main objectives of the thesis research were i) to evaluate the importance of timing of sampling in the use of the CPET method (I, II), ii) to identify chironomid indicators of different environmental conditions (II, III, IV), and iii) to compare performance of the CPET method and more traditional sampling techniques in detecting anthropogenic impacts and chironomid species composition (III, V). I also determined emergence patterns of lotic chironomids in southern Finland (II, IV). Timing of sampling was found to be a critical design factor in the application of the CPET, especially if the trophic gradient between study sites was short. Sampling occasions need to match with the emergence periods of indicator chironomid taxa to ensure the maximum likelyhood of detecting human impacts, if any exist. However, the optimal timing of sampling varies spatially and is dependend on several environmental factors, such as latitude, altitude and trophic gradient. The shift in taxonomic composition of emerging chironomids was found to be especially rapid in spring, and tended to decrease towards autumn. This was probably due to the short emergence periods of some spring-emerging univoltine species, with their annual emergence taking only a few weeks. In contrast to whole genera, the detection of a certain species may require accurate timing of sampling. Thus, among-site differences observed at species level may reflect spatially varying emergence patterns rather than true differences in community composition. On the other hand, because of the among-species variation in species' tolerances towards, for example eutrophication, genus level identification may mask subtle differences between study sites. Nevertheless, for most monitoring purposes genus level identification seems practical and adequate, although species level resolution is desirable. Comparisons of the CPET method and more traditional grab sampling showed that pupal exuvial samples provided a more complete picture of the chironomid fauna, and that this information was obtained cost-effectively. Further, the integrative nature of the CPET was found to be critically important in the assessment of both lotic and lentic habitats. Sampling only a single macrohabitat type may result in biased estimates of the ecological condition of the whole water body. Further, in comparison to profundal grab samples, integrating species from various habitats using the CPET method appeared to have only a minor negative influence on the signal strength. Determination of emergence patterns of lotic chironomids showed that nearly 200 chironomid species occurred frequently in rivers of southern Finland. A major proportion of species richness was accounted for the sub-families Chironominae (emerging mainly during the summer months) and Orthocladiinae (spring and autumn). Overall, these studies demonstrated that the CPET is a cost-effective and sensitive method for the assessment and monitoring of freshwaters, and should be considered as an alternative and/or supplementary tool to more traditional sampling methods.

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Superoxide, the product of the one-electron reduction of dioxygen, is a molecule of enormous importance. It participates in a variety of critical physiological processes and is also an important component of fuel cells where it is an intermediate in the cathodic reaction. However, the electrochemical behavior of superoxide, mainly its reduction, is not well understood. Here, the electrochemical behavior of superoxide has been investigated in acetonitrile on glassy carbon electrodes, through cyclic voltammetry experiments. By stabilizing the electrogenerated superoxide, aprotic solvents afford an opportunity to study its electrochemical reactions further. Superoxide was generated electrochemically from dioxygen at the first voltammetric peak. In the presence of hydrogen-bond donors (water, methanol, 2-propanol), the superoxide forms a complex with the donor resulting in a positive shift in the formal potential which can be analyzed to obtain formation constants for these complexes. Stronger acids (2,2,2- trifluoroethanol, 4-tert-butylphenol) result in protonation of superoxide followed by reduction to produce HO₂-. On scanning to more negative potentials a second peak is observed which is irreversible and extremely drawn out along the potential axis indicating a small value of the transfer coefficient α. Addition of hydrogenbond donors, HA, brings about a positive shift in this peak, without a noticeable change in shape. The reaction occurring at the second peak is a concerted proton-coupled electron transfer (PCET) in which the electron is transferred to superoxide and a proton is transferred from HA to superoxide forming HO₂- and A- in a concerted process. We estimate the standard potential for this reaction for the case of water as the donor. This value suggests that the reaction at the second peak occurs at very high driving forces. Kinetic simulations using both Butler-Volmer and Marcusian schemes were performed to estimate the kinetic parameters. The unusually low rate constants obtained suggest high nonadiabaticity for this PCET reaction. The reaction was also found to proceed with an unusually large reorganization energy. Consistent with a PCET, a kinetic isotope effect, HA vs. DA, was detected for the three hydrogen-bond donors.

Wetland resources in South Florida are regulated at three redundant jurisdictional levels: local or municipal regulations set forth by many independent jurisdictions, State regulations derived directly from Florida Statutes, and Federal regulations promulgated primarily under the Clean Water Act. All three levels of government can have jurisdiction over projects that affect regulated wetland resources, yet inconsistent policies and standards remain and continue to confound regulators despite decades of intensive coordination efforts and a rapidly growing scientific research base. The size of a wetland mitigation area is of primary consideration when evaluating its perceived ecological value, although wetland mitigation areas constructed in developed areas are typically isolated and generally make use of similar designs regardless of wetland size. The Chironomidae (Order: Diptera) are the most diverse and abundant faunal taxon in all healthy freshwater bodies and are generally considered to be a reliable and effective ecological indicator. I conducted a preliminary comparison of chironomid communities between a suite of natural and artificial wetlands, and also evaluated the effect of wetland size on the community structure of the insect family Chironomidae. Using the Chironomid Pupal Exuviae Technique (CPET), collections of chironomid exuviae from a total of seven natural and artificial mitigation wetlands were compared across site groups and also correlated to recorded environmental conditions at each study site. Chironomid species assemblages at nearly all sites were dominated by Parakiefferiella coronata, comprising nearly 36% of all collected exuviae. Species assemblages from mitigation wetlands exhibited strong similarity to the aggregate species assemblage from all sites. A greater abundance of exuviae was collected from artificial sites than from natural sites, and species assemblages collected from natural sites were dissimilar from those collected from artificial sites. No statistically significant differences in community structure were detected between larger and smaller wetlands. Environmental site conditions between natural and mitigation sites generally varied greatest in conductivity and pH. No significant gradient was identified in environmental conditions or chironomid community structure across wetlands of different size. A minor seasonal gradient in TP concentrations was observed and site S6 was the most enriched site included in this study while site S1 exhibited high conductivity for the duration of the project. Differences between chironomid species assemblages collected from natural and artificial communities may be explained by the relatively static topography, more consistent substrate composition, and less diverse hydrophyte communities present in the natural sites which have generally reached a greater state of homeostasis. However, statistical tests generally support the null hypothesis. No statistically significant differences were detected between sites based on collected chironomid communities when grouped by wetland origin (artificial vs. natural) or size. Observed differences between communities sampled from natural and artificial wetlands support regulatory concerns that artificial wetlands may not sufficiently emulate natural systems and that a constructed wetland system may take generations, or even centuries to sufficiently mimic its natural counterpart. Mitigation design complexity does appear to provide a diversity of microhabitats favorable to a greater variety of chironomids. However, a lack of statistical significance may support assertions that mitigation sites are successfully replacing natural wetlands. Implementation of CPET-based community structure analyses requires intensive labor and expertise and is not practical for regulatory purposes, but can provide robust data for effective and detailed site analysis.

Penning trap mass spectrometry (PTMS) can be used to test the Standard Model (SM) and to answer the questions related to the origin and abundance of the elements in the universe. There are several facilities worldwide specialized in PTMS and some of them can measure the masses of isotopes with half-lives in the range of milliseconds. TRIUMF’s ion trap for atomic and nuclear science (TITAN) is one such facility. In mass measurement the precision is linearly proportional to the charge state of the ion of interest. To increase the charge state, ions are charge-bred using an electron beam ion trap (EBIT) at TITAN. However, the charge breeding process introduces an energy spread among the ions which adversely affects the precision of the mass measurement. To overcome this problem a cooler Penning trap (CPET) was designed, assembled and is now being tested off-line. This thesis presents the first systematic test results of CPET. We also present the result of the first Penning trap mass measurement of the isotope 24Al, which is five times more precise than the previous atomic mass evaluation (AME2012) value. The precise and accurate mass of 24Al is important for both astrophysics and for test of the standard model (SM). The resonance energy (E_r) calculated for the 23Mg(p,gamma)24Al reaction using the ground state mass of 24Al reported in this thesis shows a 2s deviation from the direct measurement. On the other hand, tests of the SM by evaluating f_t values using isospin T = 1 nuclides have reached a high precision level. Effort is now shifting towards the T = 2 nuclides, which are far from stability compared to their T = 1 counterparts. For this reason, the ground state masses of T = 2 nuclides and of their decay products are required to be known with high precision. 24Al is the daughter of one such nucleus, 24Si. The ground state mass of 24Al reported in this thesis will be useful to test the SM. / October 2016

La performance des complexes biomimétiques utilisés comme catalyseurs pourrait résider dans le fait que, lorsqu'ils impliquent un transfert 1e-,1H+ (PCET) celui-ci ait lieu de manière concertée, évitant ainsi la formation d'intermédiaires coûteux en énergie. Par une approche expérimentale électrochimique, nous avons déterminé les paramètres gouvernant la compétition entre mécanismes séquentiel et concerté pour un PCET grâce à un composé modèle ([OsII(bpy)2py(H2O)](PF6)2). Pour ce faire, les mécanismes propres à chaque PCET présentés par le complexe d'osmium ont été identifiés : le transfert 1e-,1H+ associé au couple rédox OsII(H2O)/OsIII(OH) emprunte un mécanisme séquentiel alors que celui associé au couple rédox OsIII(OH)/OsII=O emprunte un mécanisme concerté. En comparant ces deux systèmes, nous avons pu déterminer les paramètres influençant le mécanisme concerté. Ainsi, un complexe « idéal » présentant un mécanisme concerté possède une sphère de coordination assez rigide afin d'avoir des constantes de vitesse standard élevée, un écart de ses constantes d'acidité important, une base géographiquement proche, doit être dans un environnement ne présentant pas d'anion pouvant s'associer plus fortement avec le complexe que la base et enfin répondre correctement aux critères de solubilité et stabilité chimique dans le milieu ciblé. L'étude d'un complexe de manganèse biomimétique de la superoxyde dismutase a permis d'appliquer la méthodologie mise en place lors de l'étude du complexe d'osmium et de confirmer les conclusions mises à jour par ce dernier: lorsque la concentration en espèce acceptrice de proton est importante, le processus concerté peut devenir prépondérant.