Primary production was measured on a 9.5 acre Cache Valley, Utah farm pond from July 1971 to July 1972. Polyethylene film tubes, with lids, were used to confine columns of water for determining dissolved oxygen concentration. Once a week, dissolved oxygen samples were taken at sunset, the following sunrise and sunset. Annual primary production was estimated at 1289 grams oxygen per square meter for two of the four stations, and 927 grams oxygen per square meter for the remaining two stations. The weekly data was computed at once a month intervals to see if it would be possible to get a good estimate of primary production sampling only 12 times a year~ It was found that the stations with consistent limiting factors could have been sampled once a month with good results, but stations with fluctuating limiting factors could not be sampled that way for good results.

Waste Stabilisation Ponds (WSPs) are a relatively simplistic and non-intensive wastewater treatment technology; with various WSP configurations widely employed to treat a range of different wastewaters the world over. Whilst the advantages of WSP treatment are both numerous and well recognized, performance problems relating to the presence of occasionally large and unpredictable quantities of plankton (both algal and zooplankton) biomass in the final pond effluents have posed significant operational problems for WSP operators; with this suspended biomass representing the single biggest drawback associated with the technology. Research conducted during this project was concerned with assessing a selection of so-called ‘advanced’ in-pond treatment processes for the upgrading or polishing of a final WSP effluent. The particular research emphasis was on the removal of problematic algal and zooplankton biomass from WSP effluent prior to Dissolved Air Flotation/Filtration (DAF/F) treatment and wastewater reuse at the Bolivar Wastewater Treatment Plant (WWTP) north of Adelaide. The in situ WSP upgrade systems assessed in this thesis were: the native floating plant ‘Duckweed’ (DW); ‘Rock Filters’ (RFs); and an artificial ‘Attached-Growth Media’ (AGM); all of which were assessed for their relative treatment efficacies parallel to a non-interventional ‘Open Pond’ (OP) system which served as an effective control. These performance comparisons were assessed on a pilot-scale using a custom made pilot treatment plant which was located at the Bolivar WWTP. Performance monitoring was periodically carried out over a 12 month period from July 2005–August 2006, with algal and zooplankton populations monitored in addition to the more conventional wastewater quality parameters. Results from pilot plant investigations demonstrated that of the four pilot upgrade series, the RF and AGM systems displayed the greatest treatment potential in terms of both the magnitude and reliability of suspended solids, algal and zooplankton biomass removals. The DW system was also shown to be at least as effective and in some instances significantly more advanced than the uncovered OP system in terms of its ability to significantly improve the final effluent quality of the Bolivar WSPs. Both the RF and AGM upgrades (and to a lesser degree also the DW system) were found to offer considerable potential for producing a higher quality WSP effluent for more efficient processing by the Bolivar DAF/F plant; although there were various operational advantages and disadvantages as well as varying capital establishment costs associated with each of the candidate technologies. This part of the research represented the first direct performance comparison between two popular pond upgrade technologies (i.e. RFs and DW) and also constituted the first assessment of a novel AGM for the upgrading of tertiary-level WSP effluent. In addition to this, results from ecological performance monitoring also provided the first detailed insights into algal and zooplankton population dynamics within these WSP upgrade environments. In addition to these pilot-scale WSP upgrade performance investigations, another branch of the research project investigated additional research questions regarding the survival of algal cells within these pond upgrade environments. A series of laboratory experiments attempted to recreate the in situ conditions (in terms of light and oxygen availability) that might exist within the adopted upgrade environments. Using two common WSP algal species, long-term monitoring of the physiological status of phytoplankton cells during prolonged dark-exposure under conditions of reduced oxygen availability was performed in order to assess the likely effects of these particular environmental conditions on their survival potential in situ. Results from these laboratory-based experiments showed that both algal species were capable of quickly adjusting their cellular metabolism in response to dark incubation. Results also showed that a reduced environmental oxygen concentration (25% of saturation) had no bearing on the ability of either Chlorella or Chlamydomonas species to withstand long-term dark-exposure; with both species retaining what was essentially full biological viability following up to two months of continuous dark-exposure. In an applied context, these results suggested that subjecting algal cells to conditions of simultaneous darkness and reduced oxygen availability would be expected to have no significant adverse effects on algal survivorship within an advanced in-pond upgrade system such as a duckweed-covered WSP, a rock filter or an AGM system.

Many brackish water aquaculture ventures in Australia and overseas have established ponds in coastal regions with acid sulfate soils (ASS). Acid sulphate soils are known to leach relatively high concentrations of metals, acid (metal and H+ ion) and sulfur, however very little is known about how these leached elements affect the water quality of aquaculture ponds. The main objective of this thesis was to describe the hydrochemical processes controlling the water chemistry in the water column and sediment pore water in the studied aquaculture ponds over time and space. Water samples providing the spatio-temporal data were collected from the ponds with the use of adapted sampling methods commonly used in the groundwater environment. A transect of five nested piesometers was installed in two prawn ponds at Pimpama, south east Queensland, Australia. Each piesometer nest contained a multilevel with eight outtakes, a mini ?? horizontal, and a slotted piesometer. Water samples were collected from each nested piesometer on a bi-monthly basis over the prawn-growing season. The unstable elements and water quality variables (pH, Eh, DO, EC, water temperature) were measured in the field. Stable elements were analysed in the laboratory using ICP-OES and ICP-MS. Soil samples were collected at the end of the season for elemental analysis. A number of key sediment/water interactions and processes such as precipitation/dissolution reactions, oxidation-reduction reactions, photosynthesis, adsorption and seawater buffering were identified as important controls on pond water conditions. This is the first study to provide detailed hydrochemcial analysis of the pond water over time and space and aided in identifying that even shallow water bodies can be chemically heterogeneous. Analysis of the water and sediment highlighted the selection of metals that can be associated with ASS and that are mobilised from pond sediments under certain chemical conditions. In Pond 7 Al, As, Ni and Zn concentrations were generally higher at the beginning of the grow-out season. Variability of the metal concentration was observed between the water column (0 ?? 1500 mm) and the pore-water (0 - -1000 mm). The highest concentration of Al (1044 ??g/L) and Zn (104 ??g/L) were sampled in the water column (approximately 400 mm from the surface of the pond). The highest concentration of As (130 ??g/L) and Ni (73 ??g/L) were sampled in the pore water sediment (associated with ASS). Elevated Mn and Fe2+ concentrations were also associated with the sediment pore water. The highest concentrations of Mn and Fe2+ were 4717 ??g/L and 5100 ??g/L respectively. In Pond 10, Ni concentrations (167 ??g/L) were the highest at the beginning of the grow-out season. However, As (97 ??g/L), Al (234 ??g/L) and Zn (308 ??g/L) were most concentrated during the middle of the cycle. The highest mean concentrations of these elements are As (63 ??g/L), Al (91 ??g/L) and Zn (69 ??g/L) which are each associated with the sediment-water interface. These metals are integral in degrading the pond water quality and lead to a loss of beneficial algal blooms, a reduction in pond water pH, poor growth rates and high mortality in shrimp. It is also possible that the dissolved ions and precipitated compounds that are leached from the ASS are discharged into the adjacent coastal estuary of Moreton Bay. With knowledge obtained from this PhD study, effective management and treatment systems can be developed and implemented to minimise the impact of these soils on the pond system and the water discharging into natural coastal ecosystem.

Giralang Pond was a water body, with little emergent or submerged vegetation, designed to trap fine sediment and buffer input of rising water to Ginninderra Wetland downstream. Ginninderra Wetland was designed to retain and use sediment nutrients and other potential hazardous materials in urban run-off. Water in the Wetland was more turbid and had lower magnesium concentration, redox potentials and dissolved oxygen concentration than did Giralang Pond. Water temperature was a minimum of 4 °C in the winter and reached a summer maximum of 30 °C Giralang Pond had more organisms but fewer taxa than Ginninderra Wetland. The greatest abundance in the pond resulted principally from high numbers of two numerically dominant species Calamoecia sp. and Micronecta sp.. More organisms were found in vegetated habitats of Ginninderra Wetland than open water habitats. The number of invertebrates and the number of taxa found in Typha domingensis did not differ significantly from similar estimates for Schoenplectus validus, Gambusia qffinis was the dominant predator in both water bodies. On one occasion, G. qffinis reached population densities of 35 individuals per m-2 . G. qffinis was five times more abundant in Gininnderra Wetland than in Giralang Pond and also showed a preference for vegetated areas. G. qffinis over-grazed it's prey on several occasions. G. qffinis, invertebrate predators and prey followed a pattern of a community in a stable predator-prey cycle. Prey in early spring increased population numbers and then decreased when G. qffinis and other predators increased their numbers. The pattern was further strengthened by occurring in both areas of open water and vegetated habitat types.

The impact of the market economy is a significant challenge facing Fijian rural communities. It is especially challenging for indigenous rural women who are managing the shift from a subsistence way of living to engagement in money generating activities. The challenge is more acute amongst disadvantaged populations such as women in rural communities who lack the resources and the political power to manage these challenges. The thesis provides a critical ethnographic, action-research study of the daily socioeconomic experiences of a group of Fijian village women, at this time of significant change. It provides and in-depth case study of a rural Fijian village located in the upper reaches of the Sigatoka Valley. The case study focuses on the women�s perspectives about their daily lived experiences and actions that followed from reflection on these, drawing out from these implications for indigenous Fijian women�s social progress and development. Herself, a member of the community, the researcher gathered data by a combination of participant observation, survey, diaries, focus groups and interviews. The researcher�s observations and understandings were fed back to the participants in the form of a workshop with the intention of confirmation and to provide and opportunity for action based on this reflection. It is argued that the success of managing the influence of the market economy on the villagers is to create social and political spaces and opportunities to hear and understand local epistemologies and daily lived experiences, reflexively. As an indigenous scholar, the researcher interrogates and deconstructs her own academic epistemologies and positions as a knowledge broker in order to co-construct new practices with her people. The research promises to make public Fijian village women�s knowledge, values, practices and experiences so that they can be understood by local scholars and local government development officers. Privileging the village women�s knowledge and bringing it to the core is a significant political act that might form the basis of proceeding political encounters that women will face in the development process.

<p>Dispersal is an important factor in animal ecology. Anurans (frogs and toads) are often philopatric (home loving) but some specimens in a population usually have the capacity to disperse relatively long distances. In this study I investigated the colonization of newly constructed ponds in the southwest of Sweden by three anuran species: The common toad (Bufo bufo), the moor frog (Rana arvalis) and the common frog (Rana temporaria). The ponds were constructed between two and five years ago and were now as frequently occupied as older source ponds in the area. For the common toad and the common frog there was no correlation between distance to source populations and degree of colonization. The moor frog was more common in ponds that were situated in the vicinity of older source ponds with ample populations. The main impression was that these species rapidly colonize newly constructed ponds, at least within moderate distances from source populations. There were some differences between the species though and it seems like the moor frog have more limited dispersal abilities than the other two species.</p>

Résumé Une meilleure intégration de la fougère aquatique Azolla dans les aliments de O. niloticus en vue de sa production en milieu rural a été recherchée en bassins et en étangs. Six aliments (29,2 % PB; 16,9 kJ g-1 EB, chacun) : A0, A10, A20, A30, A40 et A50 contenant respectivement 0, 10, 20, 30, 40 et 50 % de farine d’Azolla (FA) en remplacement partiel de la farine de poisson ont été testés. En bassins comme en étangs, une réduction de la croissance a été enregistrée lorsque la teneur en FA a dépassé 10 et 20 % respectivement. En étangs, les valeurs de production piscicoles (8220-5120 kg ha-1 an-1) et d’indice de profitabilité (0,42-0,89) sont similaires jusqu’à 20 % et 30 % de FA dans les aliments. L’élevage en étangs pourrait être plus avantageux en nourrissant les poissons avec A20 en étangs dont la surface est couverte à 45 % par un tapis d’Azolla. Dans les deux systèmes d’élevage, la composition des carcasses ne semble pas être affectée, excepté une réduction de la teneur en lipides totaux dans les poissons nourris avec A30, A40 et A50 en bassins et ceux nourris avec A50 en étangs. D’un point de vue environnemental, malgré que la teneur en phosphore des aliments soit passée de 1,13 % à 0,76 % en faisant varier leur teneur en Azolla de 0 % à 50 %, les compositions en phosphore (P) et azote (N) des poissons sont similaires, en bassins comme en étangs. En bassins, les quantités de P et de N rejetées par les poissons ont diminué avec l’augmentation de FA dans les aliments. De même, la quantité de P rejetée en étangs décroît, tandis que celle de l’azote est identique dans tous les traitements. La composition en acides gras des poissons élevés en bassins ressemble à celle des aliments, excepté une augmentation de la teneur en acide arachidonique (ARA) chez les poissons nourris à fort taux d’Azolla. Ceci pourrait être le fait d’une élongation et désaturation de l’acide linoléique. Les valeurs du ratio n-3/n-6 (0,08-0,17) qui en résultent sont faibles chez les poissons nourris avec A40 et A50. Le profil en acides gras des poissons d’étangs est par contre différent de celui des poissons de bassins et de la composition des aliments. Cette dissemblance est particulièrement prononcée chez les poissons nourris avec A30, A40 et A50 qui sont riches en acide éicosapentaénoique (EPA) et acide docosahexaénoique (DHA), principaux acides gras dans le plancton. Cette "signature" du plancton pourrait être due à une consommation supplémentaire de ces nourritures naturelles par ces poissons et expliquerait les valeurs élevées du ratio n-3/n-6 (0,35-0,53) dans les poissons nourris avec les aliments contenant 20 à 50 % de FA. Les paramètres de croissance et le profil en acides gras sont meilleurs en étangs qu’en bassins, et les nutriments rejétés en étangs sont relativement faibles, probablement à cause de la contribution de la nourriture naturelle. En conclusion, Azolla pourrait permettre de réduire le coût des aliments et le coût total de production des poissons, tout en garantissant un bon niveau trophique des étangs et une bonne qualité nutritionnelle des poissons produits. L’étude suggère d’utiliser la fougère jusqu’à 10 % dans les aliments en bassins et 20 à 30 % en étangs. Dans ce dernier système, une couverture des étangs de maximum 45 % de leur surface pourrait permettre de produire des poissons, en même temps qu’elle fournirait de l’Azolla à incorporer dans les aliments ou pour d’autres utilisations bénéfiques. Abstract An improved integration of the aquatic fern Azolla in diets for production of Nile tilapia O. niloticus in rural area was investigated in tanks and in ponds. Six diets (29.2% CP; 16.9 kJ g-1 GE, each) were tested, containing 0% (diet A0), 10% (diet A10), 20% (diet A20), 30% (diet A30), 40% (diet A40) and 50% (diet A50) of Azolla meal (AM) as fishmeal (FM) substitutes. The diet A0 served as a control. Growth parameters decreased, significantly when Azolla level exceeds 10% and 20% in diets, respectively in tanks and ponds. In ponds, the variation of annual fish production follows the trend in growth parameters, with values decreasing from 8220 to 5120 kg ha-1 year-1. Identical profitability index (range: 0.42-0.89) was obtained up to 30% Azolla. Feeding with A20 could be more advantageous by rearing fish in ponds covered with Azolla mat at a maximum of 45% of the water surface. In tanks and in ponds, fish carcass was not significantly affected, except for the total lipid content of fish fed 30, 40 and 50% Azolla in tanks, and those fed 50% Azolla in ponds. From an environmental point of view, phosphorus and nitrogen contents in experimental fish show similar values, both in tanks and ponds, although phosphorus content in diets varied from 1.13% to 0.76% when Azolla level increased from 0% to 50%. In tanks, phosphorus (P) and nitrogen (N) discharged as wastes by fish decreased with increasing Azolla level in diets. Also, P decreased significantly in ponds whereas identical values were found for nitrogen in all treatments. In tanks, fish fatty acids mirror the profile in diets, except for the high arachidonic acid content (ARA) in high AM-fed fish, probably as a result of elongation and desaturation of linoleic acid. This leads to a lower n-3/n-6 ratio (range: 0.08-0.17) in fish fed A40 and A50. Fatty acid composition of fish fed in ponds was different from that in fish fed in tanks, and from diets. The lower resemblance of fish composition was more pronounced in fish fed A30 to A50 in which large amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were found, reflecting closely the composition in plankton. The reason could be a supplemental consumption of plankton by those fish as a response to the deficiency in diets A30-A50. Then, the n-3/n-6 ratios (range: 0.35-0.53) were higher in fish fed A20 to A50. Growth and fatty acid composition were better in ponds, and nutrients loading into pond water were lower, probably due to the contribution of natural foods. In conclusion, Azolla use leads to reduced feed and total fish production costs, while ensuring a suitable pond trophic level and a good nutritional quality of the fish produced. The study suggests using Azolla in tanks up to 10% in diets, while up to 20-30% can be recommended in ponds. In the latter case, covering the ponds surface with Azolla mat at a maximum of 45% of its surface could lead to produce fish, while ensuring Azolla mass production for diets and other beneficial utilization.

Dispersal is an important factor in animal ecology. Anurans (frogs and toads) are often philopatric (home loving) but some specimens in a population usually have the capacity to disperse relatively long distances. In this study I investigated the colonization of newly constructed ponds in the southwest of Sweden by three anuran species: The common toad (Bufo bufo), the moor frog (Rana arvalis) and the common frog (Rana temporaria). The ponds were constructed between two and five years ago and were now as frequently occupied as older source ponds in the area. For the common toad and the common frog there was no correlation between distance to source populations and degree of colonization. The moor frog was more common in ponds that were situated in the vicinity of older source ponds with ample populations. The main impression was that these species rapidly colonize newly constructed ponds, at least within moderate distances from source populations. There were some differences between the species though and it seems like the moor frog have more limited dispersal abilities than the other two species.

<p>This research investigated the nature, source and the spatial variation of the salinity of the water used for irrigation in the urban farming area of Philippi, which lies in the Cape Flats region of the Cape Town Metropolitan Area, South Africa. The irrigation water is mainly drawn from the Cape Flats aquifer, and pumped into ponds for eventual crop irrigation. Water samples were collected in summer and in winter from fifteen selected sites using standard water sampling procedures. Each site consisted of one borehole and one pond. The samples were routinely analyzed for salinity levels, and concentrations of major and minor ions. From the same boreholes and ponds, water was sampled in summer for isotope analysis to assess effects of evaporation on the water quality and salinity. Descriptive statistics were used to display the variation in range of specific ions in order to compare them with the recommended ranges. Geographical Information Systems analysis described the spatial distribution of the salinity across the study area, and hydrogeochemical analysis characterized the various waters and detected similarities between the water samples in the study area and other waters found in the Cape Flats region. In addition, the US salinity diagram classification of irrigation water developed by Richards (1954) was used to assess the current suitability of groundwater and pond water samples collected during the entire sampling period for irrigation activities. The research indicated that the concentrations of some ions such as chloride, nitrate, potassium and sodium exceeded in places in the study area, the target range values set by the Department of Water Affairs and Forestry (DWAF, 1996) and the Food and Agriculture Organization (Ayers and Westcot, 1985). It revealed that borehole and pond water were mostly brackish across the area regarding their total dissolved salts content, and fresh water was only found in the middle part of the study area. The research found that sea water does not intrude into the aquifer of the study area, and the accumulation of salts in groundwater and soil in the study area is mainly due to the agricultural activities and partially due to the natural movement of water through the geological formation of the Cape Flats region. The conceptual model of the occurrence of the salinization process supported these findings. From this investigation it is understood that the groundwater and pond water in the study area were generally suitable for irrigation purposes but they have to be used with caution as the vegetables are classified as sensitive and moderately sensitive to salt according to DWAF Irrigation water guidelines (1996). The quality of these waters was mainly affected by the land use activities.</p>

Recent archaeological surveys on Peter Pond Lake have provided an opportunity to better elucidate the Late Woodland period of occupation in the upper Churchill River basin of northwestern Saskatchewan. Previous studies identified two pottery-bearing cultures in the region. This included the Kisis complex of the well-documented Selkirk composite, which is characterized by Winnipeg Fabric-impressed ware and dates from approximately A.D. 1300 through to the historic period. The second was a lesser-known archaeological entity represented by limited pottery recoveries from just two sites in the region. Early interpretations proposed this latter Narrows pottery represented an incursion of the plains adapted Old Womens phase into the region, with a suggested age of approximately A.D. 1000 to 1300. <p> Through a comprehensive analysis of pottery assemblages recently recovered from over twenty sites in the Peter Pond Lake region, this study was able to further validate the original description of the Kisis complex, but more significantly, propose a new pottery ware and complex for the enigmatic Narrows pottery assemblages. As a result, this pottery is now formally classified as Narrows Fabric-impressed ware and is considered characteristic of the Buffalo Lake complex. This complex is centered on Peter Pond Lake and appears to have an extensive presence in the region. Recently obtained radiocarbon dates indicate it is slightly younger than originally believed, and spanned from approximately A.D 1200 to 1500. Unlike previous interpretations, which suggest this pottery represents a plains influence in the region, the Buffalo Lake complex is considered a boreal forest manifestation, with origins that lie in the woodlands to the southeast. The pottery shares particular affinities with contemporaneous Sandy Lake ware that has a distribution extending from east-central Saskatchewan through to northwestern Ontario and Minnesota, with additional influences evident from Winnipeg Fabric-impressed ware found throughout northern Saskatchewan, Manitoba and Ontario.