This study involves tracing inputs, partitioning, and outputs of phosphorus (P) through an aquaponics system. A mathematical model was developed to describe the dynamics of phosphorus in an aquaponics nutrient solution, and to maximize P use efficiency and minimize P waste. We assessed the influence of pH on the availability and speciation of phosphorus in an aquaponics nutrient solution. By using Visual MINTEQ, a freeware chemical equilibrium model for the calculation of element speciation, solubility equilibria, and sorption for natural waters, it was discovered that high pH values favor the formation of calcium phosphate complexes, decreasing the concentration of free phosphorus in aquaponics nutrient solutions. In addition, the mineralization of organic phosphorus in aquaponics systems was evaluated using treatments with phytase supplementation to fish diets, and incorporation of a microbial inoculant in the aquaponics nutrient solution. Overall, dietary phytase and microorganisms promoted phosphorus mineralization and enhanced phosphorus utilization in aquaponics systems. In the end, we conclude that aquaponics systems can keep the same growth performance and quality of vegetable crops grown in conventional systems when the availability and dynamics of phosphorus are well managed.

Controlled environment agriculture allows the production of fresh food indoors from global locations and contexts where it would not otherwise be possible. Growers in extreme climates and urban areas produce food locally indoors, saving thousands of food import miles and capitalizing upon the demand for fresh, tasty, and nutritious food. However, the growing of food, both indoors and outdoors, consumes huge quantities of water - as much as 70-80% of global fresh water supplies. The utilization of liquid desiccants in a closed indoor agriculture cycle provides the possibility of capturing plant-transpired water vapor. The regeneration/desalination of these liquid desiccants offers the potential to recover fresh water for irrigation and also to re-concentrate the desiccants for continued dehumidification. Through the utilization of solar thermal energy, the process can be completed with a very small to zero grid-energy footprint. The primary research in this dissertation focused on two areas: the dehumidification of indoor environments utilizing liquid desiccants inside membrane contactors and the regeneration of these desiccants using membrane distillation. Triple-bore PVDF hollow fiber membranes yielded dehumidification permeance rates around 0.25-0.31 g m-2 h-1 Pa-1 in lab-scale trials. A vacuum membrane distillation unit utilizing PVDF fibers yielded a flux of 2.8-7.0 kg m-2 hr-1. When the membrane contactor dehumidification system was applied in a bench scale controlled environment agriculture setup, the relative humidity levels responded dynamically to both plant transpiration and dehumidification rates, reaching dynamic equilibrium levels during day and night cycles. In addition, recovered fresh water from distillation was successfully applied for irrigation of crops and concentrated desiccants were successfully reused for dehumidification. If applied in practice, the liquid desiccant system for controlled environment agriculture offers the potential to reduce water use in controlled environment agriculture by as much as ~99%.

The Brazilian aquaculture sector has experienced growth in recent decades, and economic data from the sector is needed to characterize the supply chain, the consumer markets and financial indicators of fish producing units. Reliable statistical data on the Brazilian aquaculture sector is also needed to aid in the research efforts toward the sector. This dissertation analyzes data collected from experiments, suppliers and consumers of tilapia and tambaqui, the two most important fish farming species in Brazil, in three essays. <p></p><div><br></div><div>The first essay aims to fill a gap in the literature by assessing the economic returns to lettuce and juvenile tilapia production in an aquaponics system. Experimental data that varied fish stocking density and feeding rate when co-producing fish and lettuce in Brazil is analyzed. Using different nonparametric efficiency testing methods, a set of undominated technologies in the form of input mix, is identified. In addition, sensitivity analysis is used to assess the ranges for prices over which the choice of technology is robust. Results from the technical efficiency analysis show that it is possible to get marketable lettuce in synchronization with the fish production cycle using a reduced level of feed. At observed average regional market prices (0.18 R$/tilapia fingerling, 2.8 R$/kg for fish feed, 20 R$/kg for juvenile fish and 1.70 R$/lettuce plant), the highest profit alternative in the experimental design is from an initial stocking density of 250 fingerlings per m3, feeding at the recommended rate, and harvesting on the 29th day. Sensitivity analysis indicates that the choice of best input combination is sensitive to only the prices of fish feed input and juvenile fish output. A complete financial analysis was based on this production strategy, and results indicate that a 10-year project is economically viable.<br></div><div><br></div><div>Consumer demand for tilapia and tambaqui product attributes is studied in the second essay. Seafood supply chains, from fish farmers to supermarkets selling direct to consumers, must understand consumer demand for product attributes to ensure production and availability of desired products. Consumers’ willingness to pay (WTP) for tilapia and tambaqui fillets was estimated taking consumer demographics into account for each of the five Brazilian regions. A random parameters logit model was used to analyze data from discrete choice experiments conducted in-person at supermarket seafood counters. On average, Brazilian fish consumers prefer tilapia to tambaqui, and fresh to frozen fillets. Stated preferences were found to be related to knowledge about fish. This study is the first known analysis of national seafood preferences considering factors such as product form, species, and familiarity with fish and fish products in Brazil. <br></div><div><br></div><div>In the third essay, a spatial analysis of the supply chain of tilapia and tambaqui is conducted with a focus on potential policy interventions and changes in the economic environment. The analysis is based on a partial equilibrium model of the sector and is the first comprehensive model of the aquaculture supply chain for Brazil. The demand component of the model is estimated econometrically using synthetic data based on the previous consumer choice experiment combined with secondary data on aggregate fish demand. The resulting demand system reflects asymmetric cross price impacts violating Samuelson’s integrability condition. Rather than imposing symmetry during estimation, the model is formulated as a complementary problem. The spatially disaggregated model is applied to the evaluation of the impact of factors such as governmental incentives (subsides of fish feed), international oil price shocks (changes in the cost of transportation), increases in consumers’ income (shifts in demand), and decreases in retailers’ margins on the regional pattern of tilapia and tambaqui production and final consumption. Changes in transportation costs, impacted by oil prices or road improvements had little impact on market outcomes. A 10% reduction on retailers’ gross margins decreased prices by 5.2% and increased quantity demanded by 5.4%, while an 8% reduction in fish feed costs due to tax cuts indicates, on average, 5.4% lower selling prices for farmers.<br></div>

<p>In this research we observed the effects of basil on stress modulation and immune response in vertebrates <i>in vitro</i> and <i>in vivo</i>. </p> <p>The <i>in vitro</i> study was done on mice spleen cell cultured with Holy basil and Thai basil to observe their proliferation stimulation to spleen cells and spleen T cell. The study was done in presence and absence of Concanavalin A (Con A)- a mitogen known as a T cell proliferation stimulator. A single cell suspension of mice spleen cells was incubated with four different dilutions of Holy and Thai basil (1:1, 1:5, 1:25, and 1:125). No significant differences have been found between control groups (cells without factor) and treatments suggesting the basils did not show any stimulation to spleen cell or spleen T cell proliferation. </p> <p>The <i>in vivo</i> study was conducted with tilapia reared in aquaponics system to observe the stress modulating property of Holy basil. The physiological and immunological responses and growth performances of stressed and basil fed tilapia have been observed. There were four groups of fish- Control (unstressed) fish fed with commercial feed, Stressed fish fed with commercial feed, Control (unstressed) fish fed with basil-supplemented commercial feed, and Stressed fish fed with basil-supplemented commercial feed. The experiment was six weeks long. The parameters which have been recorded were- serum cortisol, packed cell volume, plasma protein, hepatosomatic index, spleen-somatic index, lysozyme activity, macrophage phagocytic capacity, length, weight, and condition factor. The results did not suggest any effects of basil on stress response. But the harmful effect of stress on fish growth and immune response was evident, as the stress groups showed significantly lower length, weight and condition factor. </p> <p>The aquaponics system used in this study was also investigated for its production of the crops. Total fish production after eight weeks of placing the fingerlings in the aquaponics system were as follows- Control group: 6.00 g/L, Stressed group: 3.98 g/L. It suggests that stress can result in far less profit in aquaponics production.</p> <p>Total plant production after 5 months is 6,521.10 g/sq. m (leaf with stem of marketable size) for Holy basil and 7219.73 g/sq. m for Thai Basil. This result suggests that basils are a viable crop in aquaponics and Thai basil would be more productive as the plant crop than Holy basil when grown on aquaponics.</p>

With our ever increasing global population it will be necessary for dense urban environments to develop methods of farming locally. Not only will urban agriculture be beneficial in aiding in the solution of this growing populations need for food production, but it can help to reconnect us to our food and their processes. This dissertation explores the education and reconnection of the public with the food production cycle through the experience of building integrated agriculture, vermiculture and aquaponic systems (cultivating plants and fish symbiotically). Pretoria’s Apies River is an ideal location for the establishment of a research facility of urban ecosystemic food production. The proposed urban agriculture program will allow for hands on research and development of emerging methods and technologies related to farming in the city environment while providing a platform for public education through interaction&inspiration. / Dissertation (MArch(Prof))--University of Pretoria, 2011. / Architecture / unrestricted

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Vad gör en fiskmarknad i Stockholm? Projektet, som utgår från idén om en fiskmarknad på Skeppsbron i Gamla stan, har fokuserats på en alternativ lösning där fisk och grönsaker odlas i ett slutet system – akvaponi. Anledning till den alternativa ingången är Östersjöns dåliga hälsotillstånd, som är en följd av en lång tids ogenerade föroreningar. Östersjöfisken är i dag förbjuden att sälja som matfisk inom EU, men svenska politiker har aktivt sökt, och fått, dispens för en inhemsk försäljning av den förgiftade fisken. Kvinnor och barn avråds i dag från att äta östersjöfisk mer än tre gånger per år. Är det då hållbart att viga en så central plats som Skeppsbron åt en romantiserad fiskhall som bär färre än hundra ”lokala” fiskare under armarna, och som riktar sig till ett smalt, i huvudsak manligt kundsegment? En strategi formas för att kunna tillgodose en fiskmarknad med enbart fisk odlad på plats, samtidigt som den inre organisation och stadsrummet tas i beaktan. / What is a fish market doing in Stockholm? The project, based on the idea of a fish market on Skeppsbron in the old town of Stockholm (Gamla stan), has its focus on an alternative solution where fish and vegetables are grown in a closed system – aquaponics. The reason for the alternative solution is the bad health situation for the Baltic sea, which is the outcome of a long period of unashamed polluting. The fish from the Baltic sea is illegal to sell as food within the EU, but Swedish politicians have actively sought, and received, exemption for a regional trade with the poisoned fish. Women and children are advised to refrain from eating fish from the Baltic sea more than three times per year. Is it then sustainable to use such a central place as Skeppsbron for a romanticized fish market that pays for less than a hundred “local” fishermen, and that addresses a narrow, mainly male segment? A strategy is formed to provide for a fish market with only fish bred on location, at the same time taking in consideration the inner organization and the cityscape.

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Aquaponics is the combination of aquaculture and hydroponic technology to grow both fish and plants together in a closed-loop system. While aquaponics can play a role in increasing food security, it may also be a potential educational tool because of its interdisciplinary nature and required technological skill set. With aquaponics, students could conduct hands-on activities involving chemistry, physics and biology to solidify their understanding of a range of theories. Beyond standard science, technology, engineering and mathematics (STEM) principles, aquaponics may be related to projects on sustainability, environmental science, agriculture, the food system, health, economics, business and marketing. The interdisciplinary nature of aquaponics may make it an appealing tool for education, yet that same aspect may also make an aquaponics system challenging to implement and manage. Given this paradox, this exploratory research assesses challenges, solutions and success of aquaponics in education with a specific focus on implementation. Qualitative data were collected through phone interviews with educators (n=10) who currently, or had in the past, used an aquaponics system in an educational setting in North America. The most frequently described uses for aquaponics were flexible, hands-on teaching and learning of STEM and food-related concepts. Participants reported two broad challenges to implementing aquaponics: technical difficulties as a result of the nature of aquaponics and restrictions as a result of their school settings. Solutions given by participants were physical aquaponics system modifications and the development of intangible characteristics, especially community connections and support, passion for aquaponics and expertise. In this study, success in aquaponics in education emerged as a cyclical pattern: participants valued the overall learning experiences of aquaponics and the continued application of these learning experiences. Ultimately, these exploratory findings will help educators manage their expectations for aquaponics while establishing objectives for their particular educational settings.