Non-indigenous species can profoundly alter the ecosystems they invade and impact local economies. Growth and body condition declines of commercially fished Great Lakes lake whitefish coincide with the establishment of non-native dreissenid mussels and the cladoceran Bythotrephes longimanus. Declines in lake herring abundance—a key prey item for other commercially important species—have also been reported. Though additional stressors such as climate change may have contributed to changes in coregonid populations, they have not been thoroughly evaluated. Here, I present data that condition and contaminant declines in coregonids are associated with increasing density or warming climate, but growth declines in lake whitefish are likely due to ecosystem changes associated with dreissenids and Bythotrephes. In South Bay, Lake Huron, changes in lake whitefish diet composition and stable isotope signatures were consistent with increased reliance on nearshore resources after dreissenid establishment; lake whitefish occupied shallower habitats and experienced declines in mean diet energy densities post-dreissenid invasion. Growth of South Bay lake whitefish declined after environmental effects were statistically removed, whereas condition declines were explained best by changes in lake whitefish density. Among four lake whitefish populations, growth declined after dreissenids established, but not in uninvaded reference populations. Growth also declined among four lake whitefish populations after the establishment of Bythotrephes relative to reference populations. In contrast with growth, condition of lake whitefish did not change as a result of dreissenid or Bythotrephes invasion. Bioenergetic models revealed that activity rates increased and conversion efficiencies decreased in lake whitefish populations exposed to dreissenids, despite higher consumption rates in populations with dreissenids present. Condition declines among many lake whitefish and lake herring populations (and declines in mercury among herring populations) reflected regional differences and were not related to the presence of Bythotrephes or Mysis relicta. Declines in condition were more pronounced in northwest Ontario populations where climate has changed more dramatically than in southern Ontario. This work suggests that projected range expansions of dreissenid mussels and Bythotrephes will likely affect native fisheries, and their effect on these fisheries may be exacerbated by declining fish condition associated with climate change.

As the third most important greenhouse gas, nitrous oxide (N2O) is a stable greenhouse gas and also plays a significant role in stratospheric ozone destruction. The primary anthropogenic source of N2O stems from the use of nitrogen in agriculture, with soils being the major contributors. Currently, the annual N2O emissions from this “soil–microbe-plant” system is more than 2.6 Tg (one Tg equals a million metric tons) of N2O-N globally. My doctoral studies aimed to explore innovative strategies for N2O mitigation, in the context of environmental microbiology’s potential contribution to alleviating global warming. The bacterial enzyme nitrous oxide reductase (N2OR), naturally found in some soils, is the only known enzyme capable of catalyzing the final step of the denitrification pathway, conversion of N2O to N2. Therefore, to “scrub” or reduce N2O emissions, bacterial N2OR was heterologously expressed inside the leaves and roots of transgenic plants. Others had previously shown that the functional assembly of the catalytic centres (CuZ) of N2OR is lacking when only nosZ is expressed in other bacterial hosts. There, coexpression of nosZ with nosD, nosF and nosY was found to be necessary for production of the catalytically active holoenzyme. I have generated transgenic tobacco plants expressing the nosZ gene, as well as tobacco plants in which the other four nos genes were coexpressed. More than 100 transgenic tobacco lines, expressing nosZ and nosFLZDY under the control of rolD promoter and d35S promoter, have been analyzed by PCR, RT-PCR and Western blot. The activity of N2OR expressed in transgenic plants, analyzed with the methyl viologen-linked enzyme assay, showed detectable N2O reducing activity. The N2O-reducing patterns observed were similar to that of the positive control purified bacterial N2OR. The data indicated that expressing bacterial N2OR heterologously in plants, without the expression of the accessory Nos proteins, could convert N2O into inert N2. This suggests that atmospheric phytoremediation of N2O by plants harbouring N2OR could be invaluable in efforts to reduce emissions from crop production fields.

Är det möjligt att reducera utsläppen av växthusgaser och samtidigt nå en hållbar utveckling? Regionförbundet i Kalmar län antog utmaningen 2006 och är därmed en föregångsregion i arbetet med detta. Till år 2030 är målet att Kalmar län ska bli en fossilbränslefri region. Den största potentialen anses finnas inom nya alternativ till fordonsbränsle. Hushållens sopor innehåller organiskt matavfall som skulle kunna bli fordonsgas. Allt fler biogasmackar öppnas och gasen har vunnit framgång i takt med att kollektivtrafiken gjort satsningar. I Oskarshamns kommun sker i dagsläget ingen utsortering av organiskt matavfall. Hushållsavfallet skickas tillsammans med det organiska matavfallet till förbränning med energiutvinning i Linköping. Syftet med min studie är att göra en utvärdering av miljöpåverkan utifrån två scenarier; förbränning av allt hushållavfall jämfört med att producera biogas av matavfallet och förbränna resterande. Detta sett utifrån potentialen för området i Oskarshamns kommun. Syftet är även att titta på ekonomiska aspekter. Detta är en livscykelanalys där två metoder har använts, Global Warming Potential med ett 100 års perspektiv samt ReCiPe Endpoint. Den funktionella enheten är 1 ton hushållsavfall. Genom att röta det organiska hushållsavfallet och förbränna det övriga kan man minska miljöpåverkan till 74,6 % jämfört med att förbränna allt tillsammans. Växthusgaserna minskar då med 780 kg koldioxidekvivalenter per ton hushållsavfall. Den främsta miljövinsten blir i form av minskande klimatförändringar men att det fordrar ganska omfattande ekonomiska investeringar. / Is it possible to reduce greenhouse gas emissions while achieving sustainable development? The Regional Council in Kalmar County accepted the challenge in 2006 and is thus a leading region in this work. By 2030, the goal is that Kalmar shall become a fossil fuel free region. The greatest potential is considered to be the new alternative to vehicle fuel. Household waste includes organic waste that could become fuel for vehicles. An increasing number of biogas stations have opened and the gas has been successful as the public transports have made investments. In Oskarshamn is there no current sorting of organic waste. Household waste is sent along with the organic food waste to incineration with energy recovery in Linköping. The purpose of my study is to evaluate the environmental impact based on two scenarios: the burning of all household waste compared to producing biogas from food waste and burn the remaining. This is seen by the potential of the area in Oskarshamn. Also examining the economic perspective there is. This is a LCA where two methods were used, the Global Warming Potential with a 100-year perspective and ReCiPe Endpoint. The functional unit is 1 ton of waste. By digesting the organic waste and burning the rest, one can reduce the environmental impact to 74, 6 % compared to burning it all. The greenhouse gases then will decrease by 780 kg carbon dioxide equivalent per ton household waste. The main environmental benefits are in terms of reducing climate change, but it requires quite a significant financial investment

Warming induced changes in Arctic vegetation have to date been studied through observational and experimental field studies, leaving significant uncertainty about the representativeness of selected field sites as well as how these field scale findings scale up to the entire pan-Arctic. The purposes of this thesis were therefore to 1) analyze remotely-sensed/modeled temperature, Normalized Difference Vegeta- tion Indices (NDVI) and plant Net Primary Productivity (NPP) to assess coarse- scale changes (1982–2006) in vegetation; and 2) compare field, remote sensing and model outputs to estimate limitations, challenges and disagreements between data formats. The following data sources were used: • Advanced Very High Resolution Radiometer Polar Pathfinder Extended (APP- x, temperature & albedo) • Moderate Resolution Imaging Spectroradiometer (MODIS, Normalized Dif- ference Vegetation Index (NDVI) & Enhanced Vegetation Index (EVI) ) • Landsat Enhanced Thematic Mapper (Landsat ETM, NDVI) • Global Inventory Modeling and Mapping Studies (GIMMS, NDVI) • Global Productivity Efficiency Model (GloPEM, Net Primary Productivity (NPP)) Over the pan-Arctic (1982-2007), increases in temperature, total annual NPP and maximum annual NDVI were observed. Increases in NDVI and NPP were found to be closely related to increases in temperature according to non-parametric Sen’ slope and Mann Kendall tau tests. Variations in phenology were largely non- significant but related to increases in growing season temperature. Snow melt onset and spring onset correspond closely. MODIS, Landsat and GIMMS NDVI data sets agree well, and MODIS EVI and NDVI are very similar for spring and summer at Fosheim Peninsula. GloPEM NPP and field estimates of NPP are poorly correlated, whereas GIMMS NDVI and GloPEM NPP are well correlated, indicating a need for better calibration of model NPP to field data. In summary, increases in pan-Arctic biological productivity indicators were ob- served, and were found to be closely related to recent circumpolar warming. How- ever, these changes appear to be focused in regions from which recent field studies have found significant ecological changes (Alaska), and coarse resolution remote sensing estimates of ecological changes have been less marked in other regions. Dis- crepancies between results from model, field data and remote sensing, as well as central questions remaining about the impact of increases in productivity on soil- vegetation-atmosphere feedbacks, indicate a clear need for continued research into warming induced changes in pan-Arctic vegetation.

Global climate change (GCC) may be the most pressing social and environmental issue of our time. The use of fossil fuels tops the list of human behaviors that contribute to GCC. Several ‘alternative’ energy sources are now being considered in an effort to mitigate GCC, including—controversially—nuclear energy. Examined here were environmental worldview and faith in science as moderators of the relationship between beliefs about and attitudes toward nuclear energy (ATNE). Participants were 272 college students who completed an on-line survey. Predictor variables were beliefs about whether nuclear energy contributes to GCC (GCC-beliefs) and to energy independence (EI-beliefs). Results indicated that environmental worldview moderated the negative relationship between GCC-beliefs and ATNE. Results implied that the effectiveness of arguments salient to the current nuclear energy debate concerning GCC have a medium effect on ATNE except when people are more ecocentric in their environmental worldviews.

The most devastating effects of climate change may be avoided if humans reduce activities that produce greenhouse gases and engage instead in more sustainable ecological behaviors. The current mixed methods study of 279 undergraduate students explored whether environmental worldview, belief in climate change, knowledge of climate change, personal efficacy, and intention to address climate change influenced participants’ engagement in ecological behavior. Results indicated that those with a stronger intention to address climate change and a more ecocentric worldview reported significantly more ecological behavior. Next, the study examined whether participants’ intentions to address climate change mediated the relationship between their belief in climate change and engagement in ecological behavior and whether intentions mediated the relationship between efficacy and ecological behavior. Intentions to address climate change did not mediate the relationship between belief and ecological behavior but fully mediated the relationship between efficacy to address climate change and ecological behavior.

Arktis är den plats där den globala uppvärmningen är som mest märkbar på hela jorden (Arktiska rådet). Därför är Arktis ett intressant område att studera ur klimatsynpunkt. Enligt Gore (2006) så kan en ökning av jordens medeltemperatur på 1,5 °C leda till att de ekvatoriala områdena får en temperaturökning på 0,5 °C medan temperaturen vid Arktis kan stiga med hela 6 °C. De senaste 30 åren har medeltemperaturen vid Arktis stigit med drygt en grad per decennium (Anisimov, 2007) medan den globala medeltemperaturen för samma period endast stigit med ca 0.15 grader per decennium. Arktis tros ha varit isfritt under en värmeperiod för ca 6000 – 8500 år sedan (Founder, 2011) men det som är unikt med den aktuella situationen är att avsmältningen går så snabbt. Mycket snabbare än naturliga cykler (Gore, 2006) och det råder inom forskarvärlden ingen tvekan om att det är de antropogena utsläppen av växthusgaser som är orsaken. Frågeställningen som ligger till grund för den här rapporten är att ta reda på vilket årtal som Arktis kommer att vara isfritt. Detta görs genom att undersöka hur den Arktiska isutsträckningen minskat under perioden 1979-2011.  Isdata till beräkningarna i den här rapporten är tagna från National Snow and Ice Data Center, Boulder, Colorado USA, och värdena för temperaturerna kommer från National Aeronautics and Space Administration (NASA). Genom att med minstakvadratanpassning göra en linjär approximation av varje års minsta värde av isutsträckningen vid Arktis för perioden 1979-2011 erhålls att Arktis kommer att vara isfritt år 2062. / The Arctic is the place where global warming is most significant in the whole world (Arctic Council). That is why the Arctic is an interesting area to study from a climate perspective. According to Gore (2006), an increase in global temperature of 1.5 °C might lead to an increase of 0.5 °C in the equatorial regions while the Arctic could receive a teperature rise by as much as 6 °C . During the past 30 years, average temperatures in the Arctic have risen by more then one degree per decade (Anisimov, 2007) while the global average teperature for the same period only increased by about 0.15 degrees per decade. Arctic is believed to have been ice-free during a heating period for about 6000 - 8500 years ago (Founder, 2011) but what is unique about the current situation is that the melting is so quickly. Much faster than natural cycles (Gore, 2006) and there is within the scientific community no doubt that the anthropogenic emissions of greenhouse gases is the cause. The issue which forms the basis for this report has been to investigate how the Arctic extent decreased over the period 1979-2011 and then to attempt to determine a year for when the Arctic will be ice free. Ice data to the calculations in this report are taken from the National Snow and Ice Data Center, Boulder, Colorado USA, and the temperature values comes from the National Aeronautics and Space Administration (NASA). By making a linear approximation with the least square method of each year’s minimum value of the Arctic sea ice extent for the period 1979-2011 it is obtained that the Arctic sea will be ice free by the year of 2062.

Warming induced changes in Arctic vegetation have to date been studied through observational and experimental field studies, leaving significant uncertainty about the representativeness of selected field sites as well as how these field scale findings scale up to the entire pan-Arctic. The purposes of this thesis were therefore to 1) analyze remotely-sensed/modeled temperature, Normalized Difference Vegeta- tion Indices (NDVI) and plant Net Primary Productivity (NPP) to assess coarse- scale changes (1982–2006) in vegetation; and 2) compare field, remote sensing and model outputs to estimate limitations, challenges and disagreements between data formats. The following data sources were used: • Advanced Very High Resolution Radiometer Polar Pathfinder Extended (APP- x, temperature & albedo) • Moderate Resolution Imaging Spectroradiometer (MODIS, Normalized Dif- ference Vegetation Index (NDVI) & Enhanced Vegetation Index (EVI) ) • Landsat Enhanced Thematic Mapper (Landsat ETM, NDVI) • Global Inventory Modeling and Mapping Studies (GIMMS, NDVI) • Global Productivity Efficiency Model (GloPEM, Net Primary Productivity (NPP)) Over the pan-Arctic (1982-2007), increases in temperature, total annual NPP and maximum annual NDVI were observed. Increases in NDVI and NPP were found to be closely related to increases in temperature according to non-parametric Sen’ slope and Mann Kendall tau tests. Variations in phenology were largely non- significant but related to increases in growing season temperature. Snow melt onset and spring onset correspond closely. MODIS, Landsat and GIMMS NDVI data sets agree well, and MODIS EVI and NDVI are very similar for spring and summer at Fosheim Peninsula. GloPEM NPP and field estimates of NPP are poorly correlated, whereas GIMMS NDVI and GloPEM NPP are well correlated, indicating a need for better calibration of model NPP to field data. In summary, increases in pan-Arctic biological productivity indicators were ob- served, and were found to be closely related to recent circumpolar warming. How- ever, these changes appear to be focused in regions from which recent field studies have found significant ecological changes (Alaska), and coarse resolution remote sensing estimates of ecological changes have been less marked in other regions. Dis- crepancies between results from model, field data and remote sensing, as well as central questions remaining about the impact of increases in productivity on soil- vegetation-atmosphere feedbacks, indicate a clear need for continued research into warming induced changes in pan-Arctic vegetation.

<p>Scientists expect temperatures on Earth to get substantially warmer over the course of the 21st century, causing storm systems to intensify and sea-level rise to accelerate--these changes will likely have dramatic impacts on how the coastlines of tomorrow will evolve. Humans are also playing an increasingly important role in shaping Earth's coastal systems. Coastal scientists have only a general understanding of how these three factors--humans, storms, and sea-level rise--will alter the evolution of coastlines over the coming century, however. I conduct numerical modeling experiments to shed light on the relative importance of these factors on the evolution of coastline geomorphology.</p><p>In a series of experiments using a numerical model of large-scale (1 to 100's km) and long-term (years to centuries) coastline evolution that results from gradients in alongshore sediment transport, I explore how the patterns and rates of shoreline erosion and accretion are affected by shifts in 'wave climate' (the mix of influences on alongshore sediment transport of waves approaching from different directions) induced by intensified storm systems and the direct manipulation of the shoreline system by humans through beach nourishment (periodically placing sand on an eroding beach). I use a cuspate-cape coastline, similar to the Outer Banks, North and South Carolina, USA, as an important case study in my experiments. I observe that moderate shifts in the wave climate can alter the patterns of shoreline erosion and accretion, potentially increasing migration rates by several times that which we see today, and nearly an order-of-magnitude larger than sea-level rise-related erosion alone. I also find that under possible wave climate futures, beach nourishment may also induce shoreline change on the same order of magnitude as does sea-level rise.</p><p>The decision humans make whether or not to nourish their beach often depends upon a favorable economic outcome in the endeavor. In further experiments, I couple a cost-benefit economic model of human decision making to the numerical model of coastline evolution and test a hypothetical scenario where two communities (one 'rich' and one 'poor') nourish their beaches in tandem, under different sets of economic and wave climate parameters. I observe that two adjacent communities can benefit substantially from each other's nourishment activity, and these effects persist even if the two communities are separated by several tens of kilometers.</p><p>In a separate effort, I employ techniques from dynamic capital theory coupled to a physically-realistic model of coastline evolution to find the optimum time a community should wait between beach nourishment episodes ('rotation length') to maximize the utility to beach-front property owners. In a series of experiments, I explore the sensitivity of the rotation length to economic parameters, including the discount rate, the fixed and variable costs of beach nourishment, and the benefits from beach nourishment, and physical parameters including the background erosion rate and the exponential rate at which both the cross-shore profile and the plan-view coastline shape re-adjusts following a beach nourishment episode ('decay rate' of nourishment sand). Some results I obtained were expected: if property values, the hedonic value of beach width, the baseline retreat rate, the fixed cost of beach nourishment, and the discount rate increase, then the rotation length of nourishment decreases. Some results I obtained, however, were unexpected: the rotation length of nourishment can either increase or decrease when the decay rate of nourishment sand varies versus the discount rate and when the variable costs of beach nourishment increase.</p> / Dissertation

The effects of water vapor and carbon dioxide on temperature and heat transfer in the troposphere layer, which is less than the altitude of 10 km, in the atmosphere are presented in this work. Accounting for realistic temperature- and pressure- or concentration-dependent radiative properties, this work systematically evaluates heat transfer encountered in atmosphere. For simplicity, the heat transfer is assumed to be one-dimensional and pure conduction and radiation modes. The solar irradiation penetrates through the atmosphere within its short wavelength range near around visible range between 0.4-0.7 £gm, and absorbed and reflected by the earth ground with a gray body property. The ground emits radiation in longwave range. Water vapor is transparent to longwave range 8-12 £gm and absorbed in five long wavelength bands centered at 71, 6.3, 2.7, 1.87, 1.38 £gm, whereas carbon dioxide is absorbed in four long wavelength bands centered at 15, 4.3, 2.7 and 2.0 £gm. The computed results quantitatively show that water vapor and carbon dioxide are the most important factors affecting temperature difference around 2 Celsius degrees.