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Subject: search.filters.subject.Biomass

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    Model highlights likely long-term influences of mesobrowsers versus those of elephants on woodland dynamics
    (Wiley Online Library, 2014-06) O'Kane, Christopher A. J.; Duffy, Kevin Jan; Page, Bruce R.; Macdonald, David W.
    The potential long-term influences of mesobrowsers versus those of savannah elephants on woodland dynamics have not been explored. This may be a critical omission especially in southern African savannahs, where efforts to preserve existing woodlands are typically directed at elephant man-agement. We describe a simple browse–browser model, parameterized from an extensive review of the literature and our own data, including quantitative assessment of impala impact, from the study site, iMfolozi Park, South Africa. As there is a paucity of species-specific demographic data on savannah woody species, we modelled, in a novel approach, functional groups of plant species typical of Acacia wood-lands. Outputs suggest that over the long term (100 years), low-to-moderate densities of impala will have a similar impact on woodland structure, in terms of density of adult trees, as low-to-moderate densities of elephant. Further, the outputs highlight the apparently strong synergistic effect impala and elephant impacts combined have on woodland dynamics, suggesting that reduction or removal of either impala or elephant will radically reduce long-term destruc-tion of savannah woodlands. Recorded changes in adult tree numbers in iMfolozi broadly supported the model’s outputs.
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    Biodiesel production potential of wastewater microalgae chlorella SP. under photoautotrophic and heterotrophic growth conditions
    (BAAR, 2012-10) Viswanath, Buddolla; Bux, Faizal
    In the present study, a microalgae (Chlorella sp.) isolated from wastewater pond has been studied in both photoautotrophic and heterotrophic growth conditions in bioreactor to evaluate the cell growth rate and lipid content for biodiesel production. Maximum amount of biomass was recovered from the bioreactor of Chlorella sp. grown under heterotrophic growth conditions with 8.90 gL-1 compared to photoautotrophic growth conditions, which was almost 3.6, fold lesser than the former. Heterotrophic growth of Chlorella sp. resulted in the accumulation of high lipid content in cells compared autotrophic growth by enhancing lipid production by 4.4 fold. The results suggested that heterotrophic growth of microalgae is an efficient method for the production of biomass and high lipid content in the cells, which can reduce the cost of microalgal biomass production and microalgal oil production. The quality of the oil produced from the cells of heterotrophic growth is also superior compared the oil from photoautotrophic growth.