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With increasing global populations and demand for energy, greater strain is placed on the limited supply of fossil derived fuels, which in turn drives the need for development of alternative energy sources. The discovery of biophotolysis in Chlamydomonas reinhardtii and the development of a spectral-selective photosystem I activating/photosystem II deactivating light (PSI-light) method provides a promising platform for commercial hydrogen production systems. The PSI-light method allows electrons to pass through the photosynthetic electron transport chain while reducing radiation available for photosynthetic oxygen evolution that inactivates hydrogenase. Exploring the physiology of photohydrogen production using the PSI-light method can provide insight on how to optimize conditions for maximum hydrogen production. Through the use of photosynthetic mutant strains of C. reinhardtii, it was possible to suppress photosynthetic oxygen evolution further than using photosystem I light alone to extend photohydrogen production longevity and total yield. A preliminary investigation of an iterating light treatment revealed that longevity and yield could be increased further by providing a period of darkness to allow cells to consume evolved oxygen and resynthesize hydrogenase. Work with these mutants provided understanding that a balance of radiation was required to provide electrons to hydrogenase while limiting oxygen evolution, and that when no light was provided, fermentation of stored starch was the major contributor of electrons to hydrogen production. To determine the role of starch during hydrogen production, wild type cells were exposed to different media and light treatments and monitored for starch consumption and hydrogen production. The results indicated that starch was required for hydrogen production in the dark, but for photohydrogen production, starch likely played a minor role in contributing electrons to hydrogenase. The experiments also showed the importance of acetate in the medium during the hydrogen production phase to allow any significant photohydrogen production. The role of acetate was further investigated as a growth medium constituent that stimulates metabolic activity while reducing photosynthetic oxygen evolution when added to cells grown auto- or mixotrophically. By exposing cells to CO₂ during growth, photohydrogen production was significantly increased over cells grown only in the presence of acetate.

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This thesis is a study of the evolution and development of the flagellate green algae. The first part is a comparative study of the evolution of body size, multicellularity and segregated soma. The allometry of morphological characters, development, life history and the life cycle are also considered. The second part is an experimental test of the potential role of mutation as a determinant of the course of evolution. Mutation is directional for all the characters studied. The variances and covariances created by mutation are compared to those of 30 species of Volvocaceae; the correspondence between the two depends upon the characted examined. In the third part, the growth of germ cells grown with and without a soma is compared. The response to nutrient concentration of cells grown with an intact soma is steeper than that of cells grown without a soma. This result demonstrates a physiological advantage of soma in Volvox, attributable to a division of labour between 'source' and 'sink'.

Genomic sequence data from the three domains of life have revealed a remarkable diversity of genome architectures. The relative contributions of adaptive versus non-adaptive processes in shaping this diversity are poorly understood and hotly debated. This thesis investigates the evolution of genome architecture in the Chloroplastida (i.e., green algae and land plants), with a particular focus on the mitochondrial and plastid genomes of chlamydomonadalean algae (Chlorophyceae, Chlorophyta). Much of the work presented here describes unprecedented extremes in: i) genome compactness (i.e., the fraction of noncoding DNA in a genome), ii) genome conformation (e.g., circular vs. linear vs. linear fragmented genomes), iii) intron and repeat content; and iv) nucleotide-composition landscape (e.g., GC-rich vs. AT-rich genomes). These data are then combined with intra-population nucleotide diversity data to explore the degree to which non-adaptive forces, such as random genetic drift and mutation rate, have shaped the organelle and nuclear genomes of the Chloroplastida. The major conclusions from this dissertation are that chlamydomonadalean algae show a much greater variation in organelle genome architecture than previously thought — this group boasts some of the most unusual mitochondrial and plastid genomes from all eukaryotes — and that the majority of this variation can be explained in non-adaptive terms.

With additional research on species characteristics and continued work towards cost effective production methods, algae are viewed as a possible alternative biofuel crop to current feedstocks such as corn. Current open pond production methods involve bubbling carbon dioxide (CO_(2)) gas into the media to provide a carbon source for photosynthesis, but this can be very inefficient releasing most CO_(2) back into the atmosphere. This research began by investigating the effect of sodium bicarbonate (NaHCO_(3)) in the growth media as an alternative carbon source to bubbling CO_(2) into the cultures. The second part examined if NaHCO_(3) could act as a lipid trigger in higher (10.0 g/L) concentrations. The microalgae species Dunaliella tertiolecta (Chlorophyta), Mayamaea spp. (Baciallariophyta) and Synechoccocus sp. (Cyanophyta) were grown with 0.0 g/L, 0.5g/L, 1.0 g/L, 2.0 g/L and 5.0 g/L dissolved NaHCO_(3) in modified seawater (f/2) media. To investigate effects of NaHCO_(3) on lipid accumulation, growth media cultures were divided into two ―lipid phase‖ medias containing either 0.0g/L (non-boosted) or 10.0 g/L (boosted) NaHCO_(3) treatments. Culture densities were determined using spectrophotometry, which showed both all three species are able to successfully grow in media ameliorated with these high NaHCO_(3) concentrations. Highest growth phase culture densities occurred in NaHCO_(3) concentrations of 2.0 g/L for D. tertiolecta and Mayamaea spp., and the 5.0 g/L treatment for Synechoccocus sp. Highest growth rates occurred in the 5.0 g/L NaHCO_(3) concentration treatments for D. tertiolecta, Mayamaea spp., and Synechoccocus sp. (0.205 d-1 ±0.010, 0.119 d-1 ±0.004, and 0.372 d-1 ±0.003 respectively). As a lipid accumulation trigger two of the three species (D. tertiolecta and Mayamaea spp) had their highest end day oil indices in a 10.0 g/L treatment. Highest oil indices occurred in boosted 5.0 g/L Dunaliella tertiolecta and 2.0 g/L Mayamaea spp. (13136 ± 895 and 62844 ± 8080 respectively (relative units)). The results obtained indicate NaHCO3 could be used as a photosynthetic carbon source for growth in all three species and a lipid trigger for D. tertiolecta and Mayamaea spp.

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