There is growing evidence that global warming could become a major global environmental threat during the 21st century. The precautionary principle commands preventive action, at both national and international levels, to minimize this potential threat. Many near-term, relatively inexpensive, mitigation options are available. In addition, long-term research is required to evaluate and develop advanced, possibly more expensive, countermeasures, in the eventuality that they may be required. The utilization of power plant CO{sub 2} and its recycling into fossil fuel substitutes by microalgae cultures could be one such long-term technology. Microalgae production is an expanding industry in the U.S., with three commercial systems (of approximately 10 hectare each) producing nutriceuticals, specifically beta-carotene, extracted from Dunaliella, and Spirulina biomass. Microalgae are also used in wastewater treatment. Currently production costs are high, about $10,000/ton of algal biomass, almost two orders of magnitude higher than acceptable for greenhouse gas mitigation. This report reviews the current state-of-the-art, including algal cultivation and harvesting-processing, and outlines a technique for achieving very high productivities. Costs of CO{sub 2} mitigation with microalgae production of oils ({open_quotes}biodiesel{close_quotes}) are estimated and future R&D needs outlined.

Thesis written by a student in the UNT Honors College discussing the rise of Spanish, English, and French colonialism in the Americas, the conflicts that arose with the native populations, and alliances between the colonists and various tribes.