Global temperatures are expected to increase by 1.1 to 6.4°C over the next century and, over the same period, nitrogen inputs to terrestrial ecosystems are expected to increase as a result of increased crop fertilisation and atmospheric nitrogen deposition. Both of these global change drivers are expected to affect net carbon balance by increasing both gross primary production and ecosystem respiration, yet the balance between these processes, and the potential interactive effects of the drivers, require quantification. The ability to accurately predict the effects of warming and nitrogen addition on all components of terrestrial carbon balance will be critical in determining the likely positive feedback to rising atmospheric CO₂ from terrestrial ecosystems. Tussock grasslands are a widespread and important carbon store within New Zealand and are representative of temperate grasslands worldwide. This thesis addresses the question: Will tussock grasslands act as a positive feedback to rising atmospheric CO₂ concentration in response to soil warming and nitrogen addition? Using a combination of controlled-environment and field-scale studies of tussock grassland, net ecosystem carbon exchange was partitioned into gross primary production, ecosystem respiration and the autotrophic and heterotrophic components of soil respiration. Soil respiration in the field increased by 41% in response to a 3°C soil warming treatment and by 12% in response to a 50 kg N ha⁻¹ y⁻¹ nitrogen addition treatment. Only warming resulted in enhanced heterotrophic decomposition of soil organic matter (37% increase). However, a controlled-environment study indicated that caution must be used when interpreting temperature responses of heterotrophic respiration from root-free soils, as priming effects were shown to decrease the sensitivity of heterotrophic respiration to temperature. Measurements of net ecosystem exchange in the field showed that warming-enhanced heterotrophic respiration lead to a significant 49 g m⁻² reduction in net ecosystem carbon uptake. Neither nitrogen addition nor combined warming and nitrogen addition treatment resulted in significant changes in net ecosystem carbon balance. These results suggest that tussock grasslands will act as a positive feedback to rising atmospheric CO₂ concentration. However, increased nitrogen deposition will serve as a potential mitigating factor for climate driven feedbacks.

The vast majority of Adirondack lakes have been impacted since pre-industrial time through either regional (e.g. acidification) or local (e.g. fish stocking, liming, seepage of road salt, cultural eutrophication) environmental disturbances. Inferring changes related to climate are difficult due to the possible complexities associated with multiple stressors. Thirty minimally-disturbed ‘reference’ lakes were identified from a database of 1469 lakes using the following selection criteria: <5% shoreline development; a circumneutral pH; and no records of introduction of non-native piscivores (protecting against eutrophication, chronic lake acidification and modifications of trophic structure, respectively). As such, these ‘reference’ lakes may be useful for isolating the effects of regional changes, including climate warming, from other anthropogenic influences. A ‘top-bottom’ paleolimnological analysis of diatom assemblages was undertaken to identify changes since pre-industrial times. The uppermost sediment layer was used to represent present-day diatom assemblages, and a sediment sample from a depth of 20cm was used to represent pre-industrial conditions. Discostella stelligera, a planktonic diatom taxon, is presently the dominant species in 50% of the lakes, and showed the greatest change. D. stelligera increased by >10% in 11 of the 30 study lakes. The measured present-day chemical and physical limnological variables in the study lakes could not predict changes in the abundance of D. stelligera, suggesting that unmeasured variables, such as decreased ice cover, and changes in mixing and stratification patterns, are likely driving the observed changes in diatom assemblages. Heavily silicified tychoplanktonic Aulacoseira species declined by an average of 8.3% across the dataset. In three of the relatively deep lakes with higher concentrations of phosphorus, another planktonic diatom, A. formosa, was found to increase in abundance. Additionally, some lakes that were dominated by a high proportion of benthic taxa experienced increases in the relative abundance of benthic taxa over time. Observed changes in the relative abundances since pre-industrial times are significantly higher than the variation between replicate cores, and between two ‘pre-industrial’ sediment intervals. Further studies on the timing of changes in diatom assemblages are necessary to confirm that such changes are consistent with recent changes in climate in the Adirondacks. / Thesis (Master, Biology) -- Queen's University, 2014-05-29 21:33:42.24

Dwindling natural resources, the impact of the green house effect and infrastructure that is resource intensive are becoming a global problem. Signs of unsustainability can be identified in various events worldwide. T he above poses an important quest ion: who should be responsible for the protection of natural resources? This question is debatable when reference is ma de to groups such as governments, consumers and business organisations. However, the destruction of the environment cannot continue and it becomes a problem that should be pondered by humanity at large. This leads to the role of education in environmental protection, and in this study specifically to the education of managers. An organisation's base rests on management's philosophy, values, vision and goals. Clearly, a manager 's influence can have immense influence on the organisation, its goals and involvement in environmental protect ion. Taking the above into consideration, this study's objective is to determine if environmental education should be included in the curriculum of management learners on tertiary level. To achieve this objective, exploratory research-was used-to learn more about the dilemma or problem identified. Through interviews (qualitative research) with interest groups such as managers, lecturers and learners in management studies, the attitude of these groups were tested regarding the above objective. Based on the study the following recommendations could be made: • The state of the environment is of great concern and is a global phenomenon affecting all humanity, not only certain groups. • Managers can play a much greater role in the protection of the environment. • Governments and people in leadership positions should decide and put legislation in place that could play an important role in the protection of the environment. / Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2009.

Dwindling natural resources, the impact of the green house effect and infrastructure that is resource intensive are becoming a global problem. Signs of unsustainability can be identified in various events worldwide. T he above poses an important quest ion: who should be responsible for the protection of natural resources? This question is debatable when reference is ma de to groups such as governments, consumers and business organisations. However, the destruction of the environment cannot continue and it becomes a problem that should be pondered by humanity at large. This leads to the role of education in environmental protection, and in this study specifically to the education of managers. An organisation's base rests on management's philosophy, values, vision and goals. Clearly, a manager 's influence can have immense influence on the organisation, its goals and involvement in environmental protect ion. Taking the above into consideration, this study's objective is to determine if environmental education should be included in the curriculum of management learners on tertiary level. To achieve this objective, exploratory research-was used-to learn more about the dilemma or problem identified. Through interviews (qualitative research) with interest groups such as managers, lecturers and learners in management studies, the attitude of these groups were tested regarding the above objective. Based on the study the following recommendations could be made: • The state of the environment is of great concern and is a global phenomenon affecting all humanity, not only certain groups. • Managers can play a much greater role in the protection of the environment. • Governments and people in leadership positions should decide and put legislation in place that could play an important role in the protection of the environment. / Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2009.

Thesis (M.A.)--Humboldt State University, 2007. / Includes bibliographical references (leaves 54-59). Also available via Humboldt Digital Scholar.

Thesis (M.E.S.)--The Evergreen State College, 2007. / Title from title screen viewed (2/14/2008). Includes bibliographical references (leaves 34-40).

Thesis (Ph. D.)--Washington State University, December 2007. / Includes bibliographical references.

Thesis (Ph.D.)--McMaster University, 2006. / Supervisor: Altaf Arain. Includes bibliographical references.

Thesis (Ph. D.)--UCLA, 2008. / Vita. Includes bibliographical references (leaves 197-198).

Thesis (MFA)--Montana State University--Bozeman, 2009. / Typescript. Chairperson, Graduate Committee: William Neff. I'm here in Glacier... is a DVD attached to the thesis. Includes bibliographical references (leaf 27).