Call number: LD2668 .T4 1986 C87 / Master of Science / Chemical Engineering

This study investigated the role of grazing as a possible cause for the upper limit of distribution of algae on a typical South African south coast.

A thesis submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, Republic of South Africa, in fulfillment of the requirements for the degree of Doctor of Philosophy in Engineering. Johannesburg, 2016 / The process of photosynthesis is of great importance as it is the reaction of carbon dioxide (CO2) and water with the help of light, ’free’ energy from the sun, to form useful carbohydrates and oxygen. Photosynthesis is therefore useful both in carbon dioxide mitigation and growing bio-feedstocks towards making biofuel. This thesis aims to address two areas for analysing the photosynthesis process: 1. Looking at the physical limits of the growth; and 2. Improving the production rate of some aquatic plants, such as duckweed and microalgae. To address the first aim, the fundamental concepts of thermodynamics were used to analyse the photosynthetic process. It was found that the theoretical minimum number of moles of photons (NP) required (9–17) is less than the values reported by other researchers, suggesting that the photosynthesis process is highly irreversible and inefficient (operating at 35% efficiency or less). This is because the number of moles of photons will increase with greater process irreversibility (when the entropy generated is greater than zero). If the photosynthesis process is indeed that irreversible then the removal of heat (the heat not used by other cellular processes) by the plant becomes a major problem. It is suggested that transpiration, and other cellular processes, are the processes by which that is done, and it is shown that the water needs of the plant for transpiration would dwarf those needed for photosynthesis. Knowing the fundamental limits to growth could also be of use because if an organism was growing at a rate close to this value there would be no advantage to try to do genetic modification to improve its rate. Following the ideas presented above a spectrophotometer was used not only to obtain the absorption spectrum of algae, but it was also used to grow small samples at specific light wavelengths. The algae species researched was Desmodesmus spp., which, for example, is used to remediate waste water or as a source of feedstock for biofuel production. It also tolerates high CO2 concentrations. This simple experimental method demonstrated that a specific light wavelength (in particular the Secomam Prim spectrophotometer) 440 nm was preferred for the algae growth. It was recommended that this specific light wavelength would be best for growth. It might also be useful to know this fact particularly when designing photobioreactors, as this could reduce the amount of heat released into the surroundings and thus make the process more energy efficient. Interestingly, the wavelength for maximum growth corresponded to one of the peaks in the absorption spectra but there was no increase in growth rate corresponding to any of the other peaks. To address the second aim, the author determined how well predictions on improving the growth of algae (Desmodesmus spp. for example), based on a theoretical model, would work when tested experimentally. What the researcher found was that the method improved algae production, using the same set of equipment. The production was improved by a factor of 1.28 and 1.26 (at product concentrations 1000 mg/L and 600 mg/L respectively) when retaining 40% of the algae suspension. The method may be particularly useful when large amounts of biomass are required as there is no extra cost of purchasing additional equipment. The same model was applied to a growth profile of duckweed (Spirodela polyrhiza 8483, which is convertible into biofuel or a source of food), and the author showed that the model could work if the duckweed was provided with an added carbon source. In order to find an economical and reliable alternative to bridge the scale gap between laboratory and industrial production, the author checked if duckweed species (Spirodela polyrhiza 8483, Spirodela polyrhiza 9509, Lemna gibba 8428, Lemna minor DWC 112, Wolffia cylindracea 7340 and Wolffia globosa 9527) could be cultivated in media less expensive than the basal laboratory medium (Schenk and Hildebrandt). The author found that duckweed can be cultivated more efficiently, and in a more cost-effective manner, in the alternative media types, while maintaining growth rates, RGR 0.09 day-1, and starch contents, 5– 17%(w/w), comparable with that obtained with the conventional laboratory media. Thus, by looking at the photosynthesis process thermodynamically and experimentally, it is shown to be possible to improve the process by using concepts presented in this thesis. / MT2017

Kong Sau Lai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 209-225). / Abstracts in English and Chinese. / Acknowledgements --- p.ii / Abstract --- p.iii / Contents --- p.vii / List of Tables --- p.xi / List of Figures --- p.xxiv / Chapter Chapter 1: --- General Introduction / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Study Site --- p.4 / Chapter 1.3 --- Study Material --- p.5 / Chapter 1.4 --- General Objectives --- p.6 / Chapter 1.5 --- Organization of the Thesis --- p.6 / Chapter Chapter 2: --- Seasonal Occurrence and Reproduction of Hypnea charoides in Ping Chau / Chapter 2.1 --- Introduction --- p.10 / Chapter 2.2 --- Materials and Methods --- p.12 / Chapter 2.2.1 --- Study sites --- p.12 / Chapter 2.2.2 --- Populations of Hypnea charoides --- p.13 / Chapter 2.2.3 --- Measurement of plant length --- p.14 / Chapter 2.2.4 --- Examination of reproductive structures --- p.14 / Chapter 2.2.5 --- Environmental parameters --- p.15 / Chapter 2.2.6 --- Statistical analysis --- p.15 / Chapter 2.3 --- Results --- p.16 / Chapter 2.3.1 --- Seasonal occurrence and growth of Hypnea charoides --- p.16 / Chapter 2.3.1.1 --- A Ma Wan populations --- p.16 / Chapter 2.3.1.2 --- Lung Lok Shui populations --- p.16 / Chapter 2.3.2 --- Reproductive seasonality --- p.17 / Chapter 2.3.2.1 --- A Ma Wan populations --- p.17 / Chapter 2.3.2.2 --- Lung Lok Shui populations --- p.19 / Chapter 2.3.3 --- Other observations --- p.19 / Chapter 2.3.4 --- Environmental parameters --- p.20 / Chapter 2.3.4.1 --- Photoperiod --- p.20 / Chapter 2.3.4.2 --- Seawater temperature --- p.20 / Chapter 2.3.4.3 --- Nutrient concentrations --- p.20 / Chapter 2.3.5 --- Statistical analysis --- p.21 / Chapter 2.3.5.1 --- A Ma Wan populations --- p.21 / Chapter 2.3.5.2 --- Lung Lok Shui populations --- p.22 / Chapter 2.4 --- Discussion --- p.23 / Chapter 2.4.1 --- Seasonal occurrence and growth of Hypnea charoides --- p.23 / Chapter 2.4.2 --- Reproductive seasonality --- p.27 / Chapter 2.4.3 --- Occurrence of cystocarps and tetrasporangia on the same thallus in Hypnea charoides --- p.34 / Chapter Chapter 3: --- Algal Recruitment on Artificial Clearings / Chapter 3.1 --- Introduction --- p.50 / Chapter 3.2 --- Materials and Methods --- p.52 / Chapter 3.2.1 --- Study site --- p.52 / Chapter 3.2.2 --- Clearing experiment --- p.53 / Chapter 3.2.3 --- Investigation on the clearing and control plots --- p.53 / Chapter 3.2.3.1 --- Species composition --- p.53 / Chapter 3.2.3.2 --- Percentage cover --- p.54 / Chapter 3.2.3.3 --- Species richness --- p.54 / Chapter 3.2.3.4 --- Species diversity --- p.55 / Chapter 3.2.4 --- Statistical analyses --- p.55 / Chapter 3.3 --- Results --- p.56 / Chapter 3.3.1 --- Species composition --- p.57 / Chapter 3.3.2 --- Percentage cover --- p.58 / Chapter 3.3.3 --- Species richness --- p.61 / Chapter 3.3.4 --- Species diversity --- p.65 / Chapter 3.4 --- Discussion --- p.69 / Chapter 3.4.1 --- Species composition and percentage cover --- p.70 / Chapter 3.4.2 --- Implications on algal succession --- p.76 / Chapter 3.4.3 --- Implications for Hypnea charoides --- p.79 / Chapter 3.4.4 --- Species richness and diversity --- p.82 / Chapter Chapter 4: --- Colonization of Early Algal Assemblages on Artificial Substrata / Chapter 4.1 --- Introduction --- p.121 / Chapter 4.2 --- Materials and Methods --- p.123 / Chapter 4.2.1 --- Study sites --- p.123 / Chapter 4.2.2 --- Experimental design --- p.124 / Chapter 4.2.3 --- Investigation for optimal sampling --- p.125 / Chapter 4.2.4 --- Examination of tiles / Chapter 4.2.4.1 --- Species composition --- p.127 / Chapter 4.2.4.2 --- Species richness --- p.127 / Chapter 4.2.4.3 --- Mean density --- p.127 / Chapter 4.2.4.4 --- Percentage cover of encrusting coralline algae --- p.128 / Chapter 4.2.4.5 --- Species diversity --- p.128 / Chapter 4.2.5 --- Statistical analyses --- p.128 / Chapter 4.3 --- Results --- p.129 / Chapter 4.3.1 --- Species composition --- p.130 / Chapter 4.3.2 --- A Ma Wan tiles --- p.130 / Chapter 4.3.2.1 --- Species richness --- p.130 / Chapter 4.3.2.2 --- Algal density --- p.131 / Chapter 4.3.2.3 --- Percentage cover of encrusting coralline algae --- p.133 / Chapter 4.3.2.4 --- Species diversity --- p.134 / Chapter 4.3.3 --- Lung Lok Shui tiles at -2 to -3 m CD - Biweekly-retrieved tiles --- p.135 / Chapter 4.3.3.1 --- Species richness --- p.135 / Chapter 4.3.3.2 --- Algal density --- p.136 / Chapter 4.3.3.3 --- Percentage cover of encrusting coralline algae --- p.136 / Chapter 4.3.3.4 --- Species diversity --- p.136 / Chapter 4.3.4 --- Lung Lok Shui tiles at 一2 to -3 m CD - Monthly-retrieved tiles --- p.137 / Chapter 4.3.5 --- Lung Lok Shui tiles at -1 m CD --- p.137 / Chapter 4.3.6 --- Permanently-placed tiles in A Ma Wan and Lung Lok Shui --- p.138 / Chapter 4.3.7 --- Presence of grazers and other organisms --- p.139 / Chapter 4.4 --- Discussion --- p.140 / Chapter Chapter 5: --- Seasonal Availability of Algal Propagules at Different Water Depths / Chapter 5.1 --- Introduction --- p.170 / Chapter 5.2 --- Materials and Methods --- p.171 / Chapter 5.2.1 --- Study sites and sample collection --- p.171 / Chapter 5.2.2 --- Experimental design --- p.173 / Chapter 5.2.3 --- Examination of tiles and statistical analyses --- p.174 / Chapter 5.3 --- Results --- p.174 / Chapter 5.3.1 --- Species composition --- p.174 / Chapter 5.3.2 --- Availability of algal propagules in A Ma Wan --- p.175 / Chapter 5.3.2.1 --- Species richness --- p.175 / Chapter 5.3.2.2 --- Frequency --- p.176 / Chapter 5.3.2.3 --- Species diversity --- p.177 / Chapter 5.3.3 --- Availability of algal propagules in Lung Lok Shui --- p.178 / Chapter 5.3.3.1 --- Species richness --- p.178 / Chapter 5.3.3.2 --- Frequency --- p.178 / Chapter 5.3.3.3 --- Species diversity --- p.179 / Chapter 5.3.4 --- Comparisons between A Ma Wan and Lung Lok Shui --- p.180 / Chapter 5.3.5 --- Physical parameters --- p.180 / Chapter 5.3.6 --- Correlation --- p.181 / Chapter 5.3.7 --- Other recruits - --- p.182 / Chapter 5.4 --- Discussion --- p.182 / Chapter Chapter 6: --- General Discussion --- p.197 / References --- p.205 / Appendix A --- p.222 / Appendix B --- p.270 / Appendix C --- p.278

This study investigated the role of grazing as a possible cause for the upper limit of distribution of algae on a typical South African south coast.

Recent observations have shown that many sandstone buildings, including important components of the UK's cultural heritage, are becoming covered with green algal growths. This is likely to result from recent changes in air quality and the impacts of a changing climate. The northern regions of the UK in particular have an abundance of sandstone heritage and, given the likelihood of warmer, wetter winters here, algal growth on vulnerable monuments is likely to become a primary conservation concern over the next 50 years. Observations of sandstone monuments in the northern regions of the UK, in particular in Belfast (Northern Ireland), Sheffield and Edinburgh have highlighted that algal greening is notably patchy. This is likely due to the array of factors which affect the bioreceptivity of host substrates such as sandstone. The bioreceptivity of a substrate (its ability to become colonised by microbes such as green algae) is dependent on inherent, external and architectural factors. The role of these factors and the interrelationships between them requires further study. This thesis aims to investigate the inherent, external and architectural factors which encourage colonisation of sandstone by green algae through an integrated programme of laboratory and field experimentation. The primary objectives of this study are: to develop improved laboratory experimental methods to control and monitor algal growth, to investigate the role of external, inherent and architectural factors and to explore the fundamental role of moisture in the development of algal greening. In order to address these objectives, laboratory and field experiments have been linked within an integrated overall methodology. Short-term laboratory experiments have investigated the bioreceptivity of four British sandstones (Peak Moor, Dungannon, St Bees and 'baluster stone') to single and mixed green algal treatment with Stichococcus bacillaris, Chlorella vulgaris and Desmococcus olivaceus, under controlled conditions. Two field experiments have also been conducted. The first exposed unweathered blocks of Dungannon sandstone in the wet environment of Derrygonnelly, Northern Ireland for 30 months. The second exposed reclaimed sandstone balusters in a shaded and exposed site in central Oxford for 12 months. The laboratory and field experiments presented utlilise a range of simple and accessible methods to monitor biofilm development (for example novel methods to map biomass) and changes in substrate condition (such as monitoring surface moisture movements with weight change and hand-held moisture meters, and using light microscopy to help visualise the impact of green algal biofilms). The results presented in this thesis confirm that moisture plays a fundamental role in the development of green algal biofilms. In laboratory experiments, colonisation often occurred within a consistent moisture zone and preferential greening in field experiments was observed in areas of frequent moisture movement. External factors have been shown to have a strong influence, in laboratory experiments where marine salts were applied, these were found to delay colonisation by around seven days. Furthermore, salts resulted in inhomogeneous patterns of colonisation, similar to those observed in scoping studies conducted in Sheffield. Laboratory experiments have also demonstrated that inherent substrate factors such as high porosity and presence of certain minerals (such as clay laminations in Dungannon) can increase the primary bioreceptivity of sandstone surfaces. Field experiments have demonstrated that architectural factors such as aspect and geometry can increase the bioreceptivity of exposed samples. In particular, preferential greening was observed on the dynamically wetted south west facing blocks in Derrygonnelly and on exposed compared with shaded balusters in Oxford. Greening was also concentrated in areas of rainwater flows and stores. Investigation of the role of external, inherent and architectural factors in the development of algal greening as provided by this project, supplies useful information for those managing our sandstone cultural heritage. This will enable more informed decisions to be made over appropriate management and conservation strategies for the future.

abstract: An issue with the utilization of swimming pools is that pumps are operated an excessive number of hours to keep the pool free of debris and algae. Case in point, according to the pool industry, a pump should operate one hour for every ten degrees of ambient temperature. A dynamic model and a control strategy have been developed using Matlab/Simulink that uses environmental conditions together with chemicals that hinder or aid algae growth in order to determine algae population. This model suggests ways to function the pump on shorter time intervals to reduce energy consumption, while simultaneously maintaining algae populations at acceptable levels. Other factors included in the model are pool thermal dynamics and pool pump/filter performance characteristics, since they also have an effect algae growth. This thesis presents the first step for an alternative way of operating a swimming pool by minimizing operating costs while eliminating algae. / Dissertation/Thesis / algae simulink model / M.S.Tech Technology 2012

During the summer of 1974 chemical conditions in the lower reaches of the Willamette River, Oregon were similar to those in other rivers currently experiencing nuisance algal growth problems. Temperature and chemical nutrients are not limiting. Relatively high populations of phytoplankton and productivity values for upstream periphyton beds and surface waters suggest moderately eutrophic conditions. However, with increased depth in the lower river, and a constant euphotic zone, the amount of photosynthetically available light is reduced. With sufficient depth and complete mixing the critical depth is exceeded. Primary productivity rates are subsequently limited by low light availability in the lower river.

The influence of iron nutrition on patterns of photosynthetic behavior, nitrogen metabolism, and fixed-carbon allocation is reported for a common freshwater green alga. Cultures of Scenedesmus quadricauda were grown in Fraquil medium in which iron concentrations ranged from 1.0 μM to 0.01 μM (log 10-6 to 10-8 M, respectively). Carbon 14 and nitrogen uptake experiments were conducted at photosynthetically saturating and subsaturating photon flux densities.

Kepone®, the registered trade name for decachlorooctahydro-1,3, 4-metheno-2H-cyclobuta cd pentalen-2-one, inhibited growth and reduced rates of photosynthesis and respiration of Chlorella sorokiniana Shihira and Kraus and Chlorocbccum hypnosporum Starr. The insecticide reduced rates of respiration more than photosynthesis. Uptake of ¹⁴C-Kepone by the algae was proportional to cellular concentration. A net efflux of Kepone was exhibited by Chlorella cells after 30 minutes of incubation, whereas, equilibrium occurred within 15 minutes of incubation for Chlorococcum. Desorption of Kepone was evident when both algal species were removed from Kepone treated solutions and incubated in untreated nutrient solutions. / Master of Science