>Magister Scientiae - MSc / Marine macroalgae are known to carry diverse bacterial communities which interact with their hosts in both harmful and beneficial ways. Algae hosts provide the bacteria with a rich source of carbon in the form of carbohydrate polysaccharides such as fucoidan, agar and alginate, which the bacteria enzymatically degrade. Splachnidium rugosum is a brown alga (Phylum: Phaeophyta) that grows exclusively in the Southern Hemisphere along the temperate shores of South Africa, New Zealand and Australia. While several studies have investigated S. rugosum distribution and fucoidan production, the microbiome of S. rugosum remains largely uncharacterized. Thus, the major objective of the present study was to isolate, identify and characterize epiphytic bacterial communities associated with S. rugosum. Algae were sourced from Rooi Els (Western Cape, South Africa) during winter 2012. Culture based methods relied on a range of selective marine media including marine agar, nutrient sea water agar, nutrient agar and thiosulfate-citrate-bile-salts-sucrose agar to determine the composition and uniqueness of bacterial communities associated with S. rugosum. Epiphytic isolates were identified to species level by 16S rRNA gene sequence analysis and encompassed 39 Gram-negative and 2 Grampositive bacterial taxa. Isolates were classified into four phylogenetic groups, Gamma - Proteobacteria, Alpha-Proteobacteria, Firmicutes and Bacteriodetes. Bacteria belonging to the phylum Gamma-Proteobacteria were the most abundant, with Vibrio and Pseudoalteromonas being the dominant genera. Three isolates with low sequence identity (˂97%) to their closest relatives could possibly represent novel species. These isolates were grouped into the genera Shewanella, Sphingomonas and Sulfitobacter. All bacterial isolates (41) were screened for antimicrobial activity against the following test strains: Escherichia coli, Bacillus cereus, Staphylococcus epidermidis, Mycobacterium smegmatis Micrococcus luteus and Pseudomonas putida. Fifteen isolates (36%) displayed antimicrobial activity against one or more of the test strains, while one isolate (Pseudomonas species) showed broad spectrum antimicrobial activity against all the test strains except for E. coli. This study provides the first account of the diversity and composition of bacterial populations on the surface of S. rugosum, and demonstrates the ability of these bacteria to produce antimicrobial compounds. Despite recent advances in metagenomics, this study highlights the fact that traditional culturing technologies remain a valuable tool for the discovery of novel bioactive compounds of bacterial origin.

Philosophiae Doctor - PhD / The aim of this study was to document the intertidal and shallow subtidal species of non-geniculate coralline red algae from the South Africa south coast. The main emphasis of the study are encompassed in four research chapters and one concluding chapter focusing on: 1) the documentation of the non-geniculate coralline red algae occurring along the South Africa south coast; 2) revisiting the Leptophytum-Phymatolithon complex in order to resolve the taxonomic status of species previously ascribed to the genus Leptophytum from South African; 3) starting to prepare modern monographic accounts of the higher taxa; and 4) the production of updated keys to all the currently recognised taxa of non-geniculate coralline algae for South Africa. Although nowhere near complete, here we present our findings and report on the current biodiversity status of the non-geniculate coralline red algae after a further four years of extensive sampling.

The transduction of stress signals in plants is known to involve complex hysiological responses. In D. salina a range of stresses results in hyperaccumulation of ft-carotene and an understanding of stress responses in this organism has important biotechnological implications. In this thesis an attempt was made to elucidate the physiological components involved and establish a role for pH in response to high light stress. In order to achieve this the effect of high light stress on photosynthesis and cell productivity was measured. Results showed that photosynthetic carbon assimilation, oxygen evolution and cellular productivity was initially inhibited by exposure to high light intensities, but this inhibition was transient and was overcome by a rapid increase in all three parameters. The response of the carbon pool intermediates was also investigated. It was shown that on exposure to high light ft-carotene declined but then showed a rapid increase after about 4 hours of exposure. It was also demonstrated that the initial loss of ft-carotene was due to loss of this pigment from the photosynthetic pigment bed and that the hyper-accumulation of ft-carotene was due to accumulation of ft-carotene in lipoidal globules located in the chloroplast stroma. It was further demonstrated that there was mass movement of carbon in the xanthophyll cycle shortly after exposure to high light. This was characterized by the de-epoxidation of violaxanthin to antheraxanthin with a further de-epoxidation to zeaxanthin, thereby decreasing the epoxidation state of the cycle. Furthermore, it was shown that there was relocation of carbon from violaxanthin to the plant growth regulator abscisic acid. It was also shown for the first time in D. salina that the production of ft-carotene and operation of the epoxidation state of the xanthophyll cycle has a periodicity which is established after exposure to successive cycles of a light regime. Chlorophyll fluorescence was used together with well established ammonia stress responses to acquire a general overview of energy dissipation from the photosynthetic pigment bed. In conjunction with an understanding of xanthophyll cycle operation during exposure to high light stress it has been possible to establish a relationship between chlorophyll florescence, xanthophyll cycle operation and intracellular pH. It was also shown using chlorophyll fluorescence that after 4 hour exposure to high light a maximum fluorescence peak could no longer be induced indicating a transition at about this point from a state of reversibility to commitment of the full stress response. Nuclear magnetic resonance was used to follow intracellular pH fluxes during exposure to high light. A novel technique was developed for studying photosynthetically active organisms in the dark using nuclear magnetic resonance. These results showed that on exposure to high light stress there is rapid acidification of the chloroplast stroma and to a lesser degree of the acidic vacuole. The pH of these compartments is re-established after about 4 hours which is co-incident with the onset of fl-carotene hyper-accumulation and the loss of the induction of the chlorophyll fluorescence peak indicating an intimate relationship for fl-carotene, chlorophyll fluorescence, xanthophyll cycle operation and pH. The results from this study allow for the proposal of a general physiological stress transduction response mechanism for D. salina which is common for a range of different stresses and where intracellular pH plays a central role.

This study investigated the possible use of algal extracellular polysaccharide as a biosorbent for removal of heavy metals (copper and lead) from aqueous solutions as a means of bioremediation for metal containing effluents. This biopolymer has good biosorbent properties and a potential to provide a cost effective, selective and efficient purification system. A variety of environmental conditions induce the production of extracellular polysaccharides in algae. The production of exopolysaccharides by Dunaliella cultures was induced by nitrogen deficient conditions. A high ratio of carbon to nitrogen source considerably enhanced the polysaccharide release. Purified extracellular polysaccharide samples exhibited a monosaccharide composition consisting of the following sugars: xylose, arabinose, 2-0-methyl mannose, mannose, glucose and galactose. The relative abundance (%) of these sugars were calculated relative to xylose. The major sugar constituent was 2-0-methyl mannose, which was present at approximately 160% relative to xylose. The percentage relative abundance of other sugars was as follows: 18.8; 86.8; 85.3 and 22.3% for arabinose; mannose; glucose and galactose respectively. The identity of the various constituents were confirmed by mass spectrometry. The ability of Dunaliella exopolysaccharides to accumulate metals was investigated. The following parameters were studied because they affect metal uptake: solution pH, biomass concentration, temperature, time and metal concentration. The uptake of both copper and lead were pH dependent. However, metal uptake was not significantly affected by temperature. Kinetic studies showed that Dunaliella extracellular polysaccharides exhibit good bioremediation properties. Metal uptake was rapid. In addition, the exopolysaccharide has good metal binding capacity with an uptake capacity for lead of 80 mg/g from a solution containing initial lead concentration of approximately 40 mg/l. Competition studies revealed that the presence of a second metal in solution inhibits uptake of the other metal compared to uptake in single metal solution of that particular metal. The presence of lead inhibited the uptake of copper from approximately 65% in single metal solution to 10% in binary metal solution. The presence of copper also inhibited lead uptake, though not to the same extent. Higher concentrations of lead could not completely prevent removal of copper from solution and visa versa. The same was true for lead which could not be displaced by a four-fold concentration of copper. Instead, a certain percentage of copper was always removed showing that lead did not compete with copper for these binding sites. In conclusion it appears that, copper and lead bind to different sites on Dunaliella exopolysaccharides and that they exhibit selective or preferential removal of lead.

The rhodophytes or red seaweeds are an ancient group of organisms that are related to plants. Like terrestrial plants, they use secondary compounds to protect themselves from microbial infection and grazing by herbivores. However, unlike terrestrial plants, they produce mostly halogenated secondary compounds and rarely alkaloids. Osmundaria serrata (Rhodophyta) is found along the eastern South African coast and the Maldive Islands. Its descriptive common name is “red spirals” and the species is adapted to live in habitats with high wave action. Extracts from this seaweed had previously shown to have antimicrobial activity, but ecologically irrelevant microbes were used to test the extracts. In this study, ten bacteria were isolated from the surface of O. serrata and its habitat, and identified. Mostly aerobic and Gram-negative bacteria were isolated (Halomonas and Pseudomonas species) along with facultatively anaerobic forms (Vibrio spp.) and a Gram-positive (Marinococcus sp.). These were used in bioassays to compare the activity of extracts made from O. serrata and other seaweeds that occur in the same habitat. Marine bacteria are the initial colonizers in biofilm formation and subsequent fouling of surfaces in marine environments. The study of these bacteria in relation to their macroalgal hosts may help to control biofouling of surfaces that cause economic losses worldwide. A comparison was made between using agar dilution and microtitre methods for testing the antibacterial activity of an O. serrata extract. The microtitre method was found to be more sensitive than the agar dilution method. Possibly because e some of the bacteria on the petri plates (in the agar dilution method) were not in direct contact with the toxicant in the growth medium, but were in direct contact in the liquid medium of the wells in the microtitre plates. The extract from 0. serrata was the most active of the thirteen species of macroalgae collected from the same habitat and tested for antibacterial activity. Deformities in bacteria were observed in response to the 0. serrata extract. Increased capsule production and blebbing of the outer membranes were observed by transmission electron microscopy (negative staining). Lanosol diethyl ether was isolated from 0. serrata and tested for antibacterial activity. Lanosol is produced mainly by the rhodophytes, but it is also found in other macroalgae and fungi in lower concentrations. The compound inhibited the test bacteria with average MIC's of 0.27 ± 0.07 mg.mr1 (bacteriostatic) and 0.69 ± 0.15 mg.mr1 (bactericidal). Different forms of biofilm were observed by scanning electron microscopy on the thirteen species of macroalgae. These ranged from a very little biofilm covering on the calcified reds to complex communities on the other macroalgae. The treatment with OS04 vapour before fixation in glutaraldehyde preserved the biofilm structure better than no treatment and indicated that lipids are important in maintaining biofilm structure. Since a complex biofilm community was seen on the surface of 0. serrata, it is unlikely that lanosol functions as an antifouling agent. This chemical seems to multifunctional with antimicrobial and feeding deterrent activities. / Thesis (PhD (Botany))--University of Pretoria, 2006. / Plant Science / unrestricted

Freshwater use is a major concern in the mass production of algae for biofuels. This project examined the use of canal water obtained from the Everglades Agricultural Area as a base medium for the mass production of algae. This water is not suitable for human consumption, and it is currently used for crop irrigation. A variety of canals were found to be suitable for water collection. Comparison of two methods for algal production showed no significant difference in biomass accumulation. It was discovered that synthetic reticulated foam can be used for algal biomass collection and harvest, and there is potential for its application in large-scale operations. Finally, it was determined that high alkaline conditions may help limit contaminants and competing organisms in growing algae cultures.

Rapid urbanization has led to the generation of enormous wastewater after independence. The domestic wastewater generated in municipalities is rich in nutrients such as carbon, nitrogen and phosphorus along with other ions. The generated wastewater due to lack of adequate appropriate infrastructure including low treatment efficiencies are either untreated or partially treated and are let into water bodies. Present sewage treatment plants (STP’s) in the city are either under capacity or malfunctioning and hence are unable to meet the growing demand of burgeoning urban population. Water bodies have the ability to uptake nutrients (remediation by algae, bacteria, macrophytes) provided the wastewater inflow does not exceed the threshold. However, the sustained flow of wastewater beyond the water body’s treatment ability has led to the serious problem of nutrient enrichment in surface water bodies which is evident from algal bloom and profuse growth of invasive exotic macrophytes. This necessitates cost effective environmentally sound treatment options. The current research focuses on the characterisation of domestic wastewater fed ponds/lakes, understanding of nutrient regimes in wastewaters, pond dynamics, nutrient transformation and resource recovery. This has aided in devising an algae based treatment system for Bangalore city. The interplay between various biotic and abiotic factors governs water quality in a water body. Regular monitoring helps in characterisation of the water body and also helps in identifying the sources of external input (if any) to the system. Wastewater generated in urban localities in India, due to lack of adequate appropriate infrastructure including low treatment efficiencies are untreated or partially treated and are let into water bodies. Understanding the nature of the wastewater flow regimes and the turnover of biota with prevalent nutrient conditions is required to design treatment systems. Treatment involves breakdown of complex organism forms into simpler forms and transformations of organic nutrients into inorganic forms that are finally absorbed and assimilated by microbes as algae and bacteria. In wastewater fed urban pond systems, an array of microphytes as well as macrophytes grow and help in nutrient cycling in the system and still manage to remove nutrients to satisfactory levels. However, sustained inflow of wastewater with high nutrients results in the deterioration of the system as nutrient input exceed the supportive and assimilative capability resulting in proliferation of macrophytes, algal blooms, froth formations rendering the system anoxic that results in the loss of functional abilities of the urban pond systems. This biota in the system plays a major role in nutrient removal and recycles. Understanding the nutrient cycling aspects of urban wastewater fed systems is essential to find out the key players in treatment and for devising a sustainable treatment option with resource recovery. The review of wastewater generation, treatment systems highlight shortfall of the treatment systems and need for sustainable treatment for removal and recovery of nutrients such as C, N and P. Characterisation of Varthur water body (spatial extent 220 ha) located in the south of Bangalore city has been done through monthly monitoring for 18 months with the analyses of physico-chemical and biological. The analysis showed BOD removal of 70% (filterable) when the lake functioned as an anaerobic–aerobic lagoon for 6 months at an estimated residence time of 5 days. During this period, the biota of the lake, especially primary producers such as algae, treat the water through remediation of nutrients to nearly standard water quality levels. However, the growth and spread of invasive exotic macrophytes such as water hyacinth rendered the lake anaerobic which reduces its ability (due to absence of low algae) to treat the water. This highlights the role of algae especially Chlorophycean members as Chlorococcum sp., Chlorella sp. and Monoraphidium sp. in treating urban domestic wastewater and the scope for introducing algal ponds/lagoons to treat wastewater treatment and it may be used in a larger number of small towns to enable local reuse of water. The entire pond systems comprises of various components that are deeply affected by the biotic and abiotic factors in the system. Hence, studies on major biotic components were conducted especially on algae and macrophytes and the impact of abiotic factors as wind, light, and precipitation with seasonality’s. The diurnal and spatio-temporal variations in the dissolved oxygen as well other treatment parameters were used for zonation through multivariate analysis. Physico-chemical parameters confirm the nutrient enrichment (high Amm.-N) in the water body due to the sustained inflow of wastewater. High levels of nutrients together with BOD have resulted in the lower DO levels affecting the biological life. Study on biota revealed macrophytes altering the photosynthetic regime in the algae in water bodies thus, creating anoxia and nutrient re-suspension. The multivariate analysis showed three distinct zones (clusters) on the basis of physico-chemical variables and nutrient concentrations in the lake. The sedimentary C and N analysis showed a steady increase in the C: N ratio as a function of residence time. Importance of the various sub-systems in the water body in terms of nutrient uptake and accumulation showed algal systems to be efficient. C budgeting accounted to ~ 7 t/d i.e. ~2574 t/y, indicated that the lake is an accumulator of C. An estimated relatively high gas emission across the water/air interface (17 t/d) to carbon burial into sediments (2.3 t/d) further indicates very high emissions compared to sedimentation showing the dominance of internal C cycles. The overall mass balance, gas exchange and carbon burial balance showed Varthur water body as a major emitter of C due to high primary production, substantive allochthonous carbon inputs and intensive anthropogenic activities in the water body. Gaseous carbon emission accounted for 28 % of the total Influx C. The spatial profile of N in sediment ranged from 2280-3539 mg/kg of sediment dry mass. Very low value of N:P ratio in sediments suggested possible N limitation. The determination of ammonification and nitrification showed lower nitrification rates than the ammonification rates. The potentially mineralisable nitrogen content in Varthur pond sediments varied greatly from 21.65% to 75.54% and was strongly correlated (r2=0.85) to sedimentary TN. N budgeting showed NH4-N as the predominant Nr form for microbial uptake and is the major mechanism for nitrogen removal, followed by the sedimentation process. Bacterial biomass, algal biomass and macrophyte biomass accounted for 14, 4 and 1% N removal, respectively. Ammonium concentration and nitrification accounted for 27% and 2%, respectively. While bacterial uptake remained fairly constant throughout the year, micro-algae was the major player during monsoon and winter and macrophytes dominated Nr capture during summer among autotrophs. From the estimates, it has been observed that nearly 55% Nr was recovered, recycled as cell mass and transferred to a crop system when such N-captured water is used for irrigating fodder crops. About 45% of N input into the system was lost and methods to reduce this loss need to be evolved in the future. The spatial profile of P in sediment ranged from 2111.35-3982.03 mg/kg of sediment dry mass. Inorganic-P (IP) ranging from 1270.27-3505.73 mg/kg was found to be the major fraction (61.16-91.56%) of sedimentary P. High p values in both water columns and sediments showed potential P excess conditions. P concentrations in micro and macro-algae collected during the due course of the study (on dry biomass basis) were 0.347% and 0.939% P respectively. The P fractionation revealed metal oxide bound P (NaOH-P) and constituted major fraction of IP indicating, high concentrations of Fe and Al in sediments. High concentrations of sedimentary N and P indicated possible higher trophic status (bio-productivity/unit volume) signifying its towering nutrient status evidenced from the rank order of P fractions: NaOH-P > HCl-P > NH4Cl-P, which is specific for highly enriched water bodies. P budgeting showed that bulk of the P is trapped in sediment layer with a potential of ~50 % recovery from the sediments indicating, ~70% P retention within the system. The biotic components such as bacteria, algae and macrophytes accumulates a substantial amount of P, immobilising ~139, ~482 and ~131 tonness/yr of P. The sequential P extraction shows that ~70 % of sediment bound P is readily reducible during anoxic conditions which can potentially become bio-available to trigger algal growth. Assessment of treatment efficiency of facultative algal ponds, showed moderate treatment levels with 60 % total COD removal, 50% of filterable COD removal; 82% of total BOD removal and 70% of filterable BOD removal. The N removal efficiency was lower. However, a rapid decrease in the suspended solids after a faster euglenoids growth indicated particulate C removal by algal ingestion. Euglenoides dominated the facultative pond and Chlorophycean members were more abundant in the maturation ponds owing to variable surface BOD loadings. Significant correlations between algal biomass and nutrients indicate the importance of the type and nature of algal communities that can be used as an efficient tool for predicting the dynamics of various phases in wastewater treatment systems. Detailed morphological analysis of dominant algal species i.e. euglenoides was also performed. Euglenophycean members (>14 species) sampled from various locations in the facultative pond based system showed various striae patterns and distinct nano channels on the cell surface that might have possible role in cell secretions. Comparative assessment of treatment systems reveal that algal pond systems performed well under higher organic load with a COD removal efficiency of 70%, TN removal efficiency of 73% and TP removal efficiency of 22%. However, the facultative pond based systems were effective in suspended solid (SS) removal up to 93% and BOD removal up to 82%. The conventional wastewater treatment systems were efficient in terms of SS removal up to 88%, COD removal up to 74% and BOD removal up to 63%, but were highly ineffective in nutrient removal. The evaluation of treatment processes in mechanically aerated systems, facultative ponds and large shallow lake based systems in terms of capital and annual O&M costs, COD removal cost and land requirements reveals that the mechanical systems require 5 times more capital and O&M costs than ponds. The treatment systems were also ranked in terms of the total annual cost (e.g., capital, manpower, chemical, repair, electricity, land). It showed that algal pond systems followed by facultative pond based system are economically better choice than mechanical technologies. Finally, it was found that the large pond based systems could be economically the best option for the developing countries considering all factors, including economic viability and treatment efficiency. The treatment efficiency analysis showed that algal pond systems were the most effective options for treating urban wastewater. Culturing native wastewater species in growth media and wastewaters, assessment of efficient cell disruption and solvent systems, lipid profiles of wastewater algal species were studied. Wastewater grown algal species as Euglena sp., Spirogyra sp., Phormidium sp., Lepocinclis ovum, and Chlorococcum sp. are comparatively rich in lipids. These algae grow mixotrophically and can store substantial amount of wastewater carbon as TAG’s in varied environments. Among the different cell disruption methods used for the study, sonication was the most effective. The combination of maceration and methanol: chloroform: water (2:1:0.8, v/v) (Bligh and Dyer’s, solvent) gave highest lipid extraction yield among other combinations. Further more these wastewater algae as Lepocinclis ovum and Chlorococcum sp. were found to grow better in wastewaters. Increased lipid content was recorded during the cell cultures with accumulation of quality FAME with high saturates predominated by C16-C18 fatty acids. These wastewater algal lipids are suitable for bio-energy generation with potential biomass productivity (6.52 t/ha/yr) of wastewater-grown species as Euglena. The studies on Euglena sp. showed mixotrophic mode that offers an efficient removal of TOC, N and P from domestic wastewater without any pre-treatment. Lipid profiles of the extracted algal oil were similar to the vegetative feedstock oils, indicating a good quality fuel for energy generation. Mixed algal consortia’s bioremediation potential (removal of nutrients) with the scope for biofuel production highlights self flocculating abilities of algal consortia aided in the effective treatment of wastewater with substantial algal harvest. Studies on cultivating wastewater algal consortia in novel cascading algal parcel flow reactor (CAPFR) operating in continuous mode showed 70-80 % nutrient and ~90 % C removal with in a residence time of ~4 days with highest cell densities (0.91 g/l) and productivities (0.26 g/l/d) in the last stages. The lipid contents varied from 26-28 % with highest lipid productivities ~58 mg/l/d in the 2nd phase of the bioreactor. Most of the lipids were associated with the pigments as chlorophyll and carotenoids. Furthermore, the algal rector removed bacteria up to 4 log orders. Essential cations and phosphates were responsible for self clumping of algal biomass in the final stages with a high internal P content within the cell. The algal biomass also showed substantial exothermic peaks and high heat values (~18 MJ/kg). Studies on continuous cultivation of Dictyosphaerium sp. showed that this species could adapt to wastewater conditions and also showed good nutrient removal at lower HRT (2.5 days). The high biomass productivities with high lipid content (~36%) at low HRT in the continuous mode offer potential options for economic and feasible nutrient removal with biofuel production. Investigations on city wastewaters showed low nutrient ratio indicating C limitations and possible scope for algal wastewater treatment. Integration of algal ponds in the present treatment network requires an additional land ranging from ~0.37 to 2.75 ha to treat an MLD of wastewater depending on the nutrient content and influent waters fed to algal systems. The treatment plants require an additional ~1.6 ha of land to treat 1 MLD of wastewater considering an average N and P values of 18 and 5 mg/l. The continuous algal bio-processes implemented at decentralised levels would help in the economical ways for nutrient removal and recycling of the nutrient free waters after treatment. This meets multiple objectives of low cost treatment of wastewater, nutrient recovery and fuel production. Algal nutrient capture and consequent biofuel production would ensure sustainability through i) water purification ii) nutrients capture and iii) biofuel to meet the growing energy demand, and would be an optimal treatment option for urban wastewater. The thesis consists of 10 chapters and basically deals with the development of a sustainable and economically viable bioprocess for wastewater treatment and biomass production. Chapter 1 provides a brief introduction to wastewater; domestic wastewater composition, generation and treatment in developing nations and in the country and review of the various techniques for treatment of domestic wastewaters, advantages of algal processes in nutrient removal (C, N and P) and production of valued by-product such as lipid generation, for its use as biofuel. Chapter 2 is based on primary field investigations in a wastewater fed urban water body/pond systems involving monthly sampling and analysis of various physico-chemical and biological parameters. Assessment of treatment capabilities of the continuous systems through detailed characterisation of treatment parameters is explained in the second chapter. Chapter 3 discusses the role of the major biotic (algae and macrophytes) and abiotic factors in nutrient transformations, the diurnal variations in parameters especially dissolved oxygen, multivariate spatio-temporal analysis of functional abilities for zoning, the activities in the sludge/sediment and transitions in the CN ratio as a function of residence time. Chapter 4 involves studies in C, N and P quantification and budgeting in such pond systems and partitioning of the nutrients and their distribution in various biotic and abiotic subsystems. This chapter also highlights the major nutrient losses from the system and un-utilised nutrient stocks, paving way for beneficial use of nutrients from such man made lagoon wastewater systems. Chapter 5 discusses the mechanisms and efficacies of algal pond based treatment systems through a detailed study and highlight its advantages over the mechanical ASP based systems. This has been done through a comparative assessment of treatment efficiency, economics and environmental externalities. This study also provides necessary insights and potential of wastewater algal species such as Euglena for its abilities in nutrient removal and biomass generation. This provides insights to algal treatment options for optimal resource recovery and utilisation from wastewaters. Chapter 6 focuses on testing the growth, biomass and lipid production of various wastewater algae isolated from treatment ponds. The chapter identifies suitable cell disruption and extraction routes for efficient lipid extraction and assesses the potential of these wastewater grown algae for regional and national biofuel production. Chapter 7 discusses the effectiveness of wastewater grown Euglena sp. and algal consortia in nutrient removal and as a source of lipids for biofuel generation. Chapter 8 involves the design and operation of a continuous algal (uni-algal/algal consortia) bioreactor devised taking insights from earlier field based studies and their potential as efficient urban wastewater treatment systems. Chapter 9 discusses the present nutrient levels in the city wastewaters and also an analysis of the temporal and spatial variation of nutrients in city sewers and elaborates the scope for integration of the algal modules i.e. continuous algal bioreactors (designed in the previous chapter) into existing STP’s. Chapter 10 elaborates significant contributions and outcome of the research.

The autecology of the estuarine alga, Blidingia minima var. subsalsa (Kjellman) Scagel (Chlorophyceae) was considered with regard to its growth, reproduction and distribution. Studies were conducted on the Squamish River estuary, British Columbia, from May 1974 to July 1975 and in the laboratory from January to August 1975. The major environmental factors considered were light, temperature, salinity, nutrients and desiccation. The alga occurred on the Squamish River delta in the upper intertidal zone. Biomass, as estimated by percent cover, increased in the period March to early May, then remained stable or decreased during spring runoff in May and June, finally increasing to a maximum in August. Increases in percent cover were associated with brackish salinity, high light intensity, high air temperature, considerable desiccation, an absence of algal competitors and possibly favourable ion ratios. The three factors investigated in the laboratory (temperature, salinity and nutrients) interacted in their effect on net photosynthesis. Reproduction in the laboratory occurred by release of quadri-flagellate and isomorphic biflagellate swarmers. Some biflagellate swarmers fused and germinated, producing isomorphic plants. The period of swarmer release was from January to early May. The alga was perennial but during the winter only its prostrate basal disc was present. Maximum vertical distribution was from 1.5 to 4.0 m above chart datum (lowest low water). Maximum percent cover occurred at ca. 3.25 m. The upper limit appeared to be associated with unfavourable osmotic conditions, e.g. rain or desiccation, and the lower limit with low light intensities. Horizontal distribution was limited by absence of salt water on the freshwater side and competition from Fucus distichus subsp. edentatus (De la Pylaie) Powell on the marine side of the estuary. Blidingia minima var. subsalsa1s geographical and habitat distribution was also examined by reference to literature reports and herbarium collections. The species is cosmopolitan, occurring in every ocean except the Indian and Antarctic with most reports from polar and temperate regions. The variety occurs in brackish, marine and freshwater habitats. / Science, Faculty of / Botany, Department of / Graduate

Benthic algal ecology and primary pathways of energy flow were considered on the Squamish River delta at the head of Howe Sound, a fjord-type estuary. The study elucidated the structure and function of major autotrophic components of the estuarine ecosystem. Benthic algae were investigated with regard to species composition and distribution and the capacity for energy conversion, input to the system and storage. Comparisons were made with existing information on the vascular plant component of the ecosystem. The benthic algal community was studied by regular field sampling of major macroalgae and microalgal associations with a monitoring of physical-chemical environmental factors. Presence of an alga in the estuary was a function of its osmoregulatory capabilities. Establishment and temporal-spatial distribution patterns were controlled by substrate-habitat preference and availability and the interaction of light, interspecies competition, desiccation, temperature and salinity, light being of greatest importance. Carex lyngbyei Hornem., the dominant vascular plant, had a significant effect on distribution of benthic algae through light restriction during Its summer growth period and action as a substrate during the winter. Total species diversity, biomass and distributional area of benthic algae were greatest at the latter period. The effect of ecosystem structure on function was investigated by analysis of energy flux through major benthic algal producers. Comparisons were made of the total amount of energy input attributable to benthic algae and vascular plants. The importance of an algal producer to energy flux•m⁻² was a function of either high primary productivity, photosynthetic efficiency and caloric content, or in the case of diatom dominated micro-algal associations, high caloric content alone. Distribution, reflecting the presence of suitable substrate-habitat, modified this pattern. Macroalgae having high energy input•m⁻² (Monoetroma oxyapermum (Kutz.) Doty, Pylaiella littoral-is (Lyngb.) Kjell.) were of minimum importance to total energy input. Two microalgal associations (Association E, diatom dominated, Association G, Ulothrix flaoca (Dill.) Thur. dominated), each with low energy input-m but with wide distribution and high photosynthetic efficiency and caloric content contributed a total of 8H% of available energy attributable to benthic algae. Benthic algae account for a maximum of ca. 7% of total energy input to the delta ecosystem compared to ca. 90$ by vascular plants and 3% by addition of organic matter. The majority of energy for the detrital based ecosystem comes from vascular plants and becomes available after a lag period allowing decomposition. Benthic algae are significant to the ecosystem as a readily available, continually present energy source requiring little or no breakdown for utilization and not for total energy input. Energy is available as either dissolved or particulate organic matter. Of the latter, ca. 49$ is removed to the estuary, 33% incorporated into the sediments of the delta and 18$ used by consumers in the delta ecosystem. / Science, Faculty of / Botany, Department of / Graduate

Orientador: Fosca Pedini Pereira Leite / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T11:20:12Z (GMT). No. of bitstreams: 1 Bueno_Marilia_D.pdf: 1421870 bytes, checksum: 37eb3d9230e7741798f121407dee5d97 (MD5) Previous issue date: 2015 / Resumo: Algas calcáreas articuladas estão presentes em costões rochosos ao redor do mundo e formam densos tapetes, os quais abrigam uma fauna muito rica de invertebrados. Dentre eles, os anfípodes são dominantes e sua associação com estas algas foi investigada. Inicialmente foi feita a caracterização do habitat. A biomassa das algas e a abundância total dos anfípodes não diferiram entre as estações do ano, já a composição de espécies de anfípodes apresentou variação, a qual foi atribuída principalmente ao padrão de ocorrência de duas espécies de hialídeos, Apohyale media e Hyale niger, que são dominantes nas algas calcáreas. A biomassa das algas também não variou conforme exposição à ação de ondas. Diferenças na abundância total dos animais foram observadas, sendo encontrados mais animais nos costões mais expostos às ondas. Neste tópico, os tanaidáceos foram incluídos e apenas duas espécies foram encontradas, cada uma associada à um grau de exposição à ação de ondas. Leptochelia aff. dubia foi encontrada apenas nos costões abrigados, enquanto Zeuxo coralensis apenas em costões expostos. Os tapetes de algas coralinas são verticalmente extensos a ponto de terem características físicas (quantidade de sedimento e tamanho de grãos) e biológicas (abundância e composição de espécies de anfípodes) distintas entre as zonas superior e inferior do mesmo tapete. Após a caracterização do habitat, sua utilização pelos anfípodes foi examinada com relação à estrutura (arquitetura) das algas, a altura de ocorrência das algas no costão rochoso e o papel do sedimento na seleção deste habitat. O volume intersticial foi extremamente variável dentre as cinco algas estudadas entretanto, para todas as algas, quanto maior o volume intersticial, maior a abundância dos anfípodes. O habitat formado pelas coralinas, independente da altura no costão, parece ser o fator mais importante na seleção pelos anfípodes. Com relação ao sedimento, sua retenção nos tapetes de algas não se mostrou sazonal e não foi observada relação com a abundância dos anfípodes. Os experimentos de laboratório corroboraram o padrão observado em campo e não indicaram um importante efeito da adição do sedimento na seleção de habitat pelos hialídeos. A malha intrincada formada pelas frondes das algas calcáreas permite a retenção, além do sedimento e da matéria orgânica associada à ele, de diferentes tipos de alimento como microalgas e componentes da meiofauna. Essa gama de itens alimentares pode ser importante na seleção deste local pelos anfípodes, já que a alimentação da alga em si não ocorre, e explicaria a grande variedade de hábitos alimentares apresentados pelos anfípodes associados. A seleção do habitat de coralinas pode também estar relacionada à proteção contra a dessecação, já que retenção de água entre as frondes mantém o ambiente úmido nos períodos de emersão / Abstract: Articulated calcareous algae are distributed on rocky shores worldwide forming dense mats and harboring rich invertebrate assemblages. Amphipods are dominants and their association with coralline algae was investigated. First, the habitat characterization was done. Algae biomass and amphipods abundance did not differ among seasons, but species composition showed a variable pattern mainly in response to occurrence patterns of the dominant hyalids Apohyale media and Hyale niger. Algae biomass did not vary between degrees of wave exposure, however, more amphipods were found at exposed shores. Tanaids were included and an interesting spatial segregation was observed. Only two species were found, each one associated to a degree of wave exposure. Leptochelia aff. dubia was found at sheltered shores, while Zeuxo coralensis at exposed shores. Coralline mats are wide enough to have distinguished upper and lower zones based on physical (amount of sediment and grain size) and biological (amphipods abundance and species composition) features. After characterizing the habitat, its usage by the amphipods was examined through algae structure (architecture), height on shore and the effect of sediment loads on habitat selection. Interstitial volume was highly variable among the five algae studied and a strong positive relation between interstitial volume and amphipods abundance was observed. Coralline habitat, regardless of the height on shore, was probably the main factor governing habitat selection. Sediment retention at coralline mats was not seasonal and no relation with the amphipods was found. Laboratory experiments corroborate the observed field patterns and added sediment had no effect on habitat selection by the hyalids. The intricate canopy of coralline algae allowed retention, not only of sediment and organic matter, but also of microalgae and meiofauna. This wide array of food items may be important for coralline habitat selection by the amphipods, since they do not feed on coralline itself. In this case, coralline could be an important source of food, allowing the coexistence of amphipods having different feeding habits. Water retention may also play an important role, since habitats are maintained humid during emersion periods / Doutorado / Ecologia / Doutora em Ecologia