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Thesis (Master's)

University of Akureyri > Viðskipta- og raunvísindasvið > Meistaraprófsritgerðir >

Please use this identifier to cite or link to this item: http://hdl.handle.net/1946/41997

Title: 
  • From science to innovation : investigation about a Saline Aquaponics System : production performance and pilot research on the biostimulating properties of solid wastes
Degree: 
  • Master's
Abstract: 
  • Global needs to meet basic food and water requirements are driving the search for new frontiers of sustainable production, such as aquaponics in brackish and saltwater. In addition to being an efficient production sector with a relatively low environmental impact, it can address increasingly frequent environmental issues such as the reduction of freshwater resources and the gradual increase in soil salinity.
    In the present pilot study adaptability, productive performance, and final yield of fish and plants farmed and grown in a low-tech saline water-based aquaponic system were investigated. A total of 261 black bullhead catfish (Ameiurus melas), paired with 72 cherry tomato (Solanum lycopersicum var. cerasiforme) seedlings, were equally divided into three experimental treatments namely: low salinity (LS; 0.5‰), medium salinity (MS; 3.5‰), high salinity (HS; 6.0‰). The different salinities did not significantly affect water quality. Traits such as temperature, dissolved oxygen concentration in the water, daily water consumption due to evapotranspiration, pH, and total ammonia nitrogen remained stable over time and followed seasonality. As for fish, the growth of black bullhead catfish ended with the average final weight of the fish of 193 ± 50 g and an average survival of 76 ± 13%. Some limited, albeit significant, differences were found between experimental treatments in the morphometric indices; specifically, the condition index and cranial index were affected by the treatment. The eviscerated carcass yield and viscerosomatic index were also slightly influenced by treatment, while no significant differences were recorded on the average yield of fillets and pH. As for the horticultural side, during the growth of cherry tomatoes plants (i.e., height, number of internodes, soil-plant analysis development (SPAD), and phenological development, no significant differences were found between treatments, except for the SPAD values. In terms of fruits production, the effect of different salinities was
    noticed on the number of developed bunches per plant, fruits per bunch, weight per bunch, and size of the fruits. Analyses on the vacuolar juice of fruits also showed that the sugars content, titratable acidity, and pH were affected by the treatment.
    In parallel, the pilot study testing the biostimulant properties of aquaponic solid waste showed that its application as a hydrolysate on lettuce (Lactuca sativa var. capitata L.) and watercress (Lepidium sativum L.) had some degrees of gibberellin-like response in the
    lettuce seedlings proving a positive hormonal role in hypocotyl elongation when compared to the gibberellic acid treatments. The best gibberellin-like response was found at dilutions of 25,000 ppm and 15,000 ppm. In contrast, no clear and marked response appeared on
    watercress roots growth inhibition following the aquaponic hydrolysate application when compared to indoleacetic acid treatments. The existence of a possible auxin-like hormonal effect was disproved due to the great variability and conflictual of the obtained results.

  • Abstract is in Icelandic

    Þörfin fyrir matvæli og vatn á heimsvísu hefur knúið áfram leit að nýjum vaxtarjöðrum fyrir sjálfbæra fæðuframleiðslu, þar á meðal er samrækt (e. aquaponics) í ísöltu og söltu vatni. Auk þess að vera skilvirk framleiðsluaðferð, með fremur lítil umhverfisáhrif, getur aðferðin haft áhrif á algeng umhverfisvandamál svo sem samdrátt ferskvatnsauðlinda og aukningu í jarðvegsseltu. Í þessari frumkönnun var notast við „lágtækni“ saltvatns samræktarkerfi til að rannsaka aðlögunarhæfni, framleiðslugetu og framleiðni fisks og plantna sem voru ræktaðar. Alls var 261 „black bullhead catfhish“ (Ameiurus melas), paraðir við 72 kirsuberjagræðlinga (Solanum lycopersicum var. cerasiforme) og dreift jafn í þrjár ólíkar lausnir: lágsaltlausn (LS; 0.5‰), meðalsaltlausn (MS; 3.5‰), hásaltlausn (HS; 6.0‰). Mismunandi seltustig vatnsins hafði ekki áhrif á vatnsgæðin. Einkenni á borð við, hitastig, súrefnismagn vatnsins, dagleg eyðsla vatns vegna uppgufunar, pH gildi og heildar ammóníumnítrad hélst stöðugt yfir tímabilið í samhengi við árstíðarsveiflur. Fiskarnir enduðu með meðal þyngdina 193 ± 50 g og meðaltals lífslíkur voru 76 ± 13%. Ákveðnir afmarkaðir, en þó mikilvægir, breytileikar fundust milli tilraunahópa hvað varðar sköpulag, nánar tiltekið heildarástand (e. condition index) og höfuðstærðar (e. cranial index), eftir ólíkri meðhöndlun. Meðhöndlun hafði lítils háttar áhrif á það hve mikið slægður fiskur gaf af sér og hið sama gildir um óslægðan fisk, en engin marktækur munur var á meðalþyngd flaka og pH-gildis. Á garðyrkjuhliðinni, þ.e.a.s. hvað varðar, hæð, fjölda stöngla, SPAD (e. soil-plant analysis development) og náttúrufarsfræði, fannst enginn marktækur munur á milli meðhöndlunar nema hvað varðar SPAD gildi. Hvað varðar vöxt og uppskeru ávaxta, var ekki munur milli ólíkra saltlausna hvað varðar fjölda klasa á plöntu, fjölda ávaxta í klasa, þyngd klasa og stærð ávaxtanna sjálfra. Greining á safa ávaxta sýndi að meðhöndlun hafði áhrif á magn sykra, títranlegt sýruinnihald og pH gildi. Samhliða sýndi frumkönnunin að áburðargildi úrgangs í föstu formi frá samræktinni hafði nokkur vaxtarörvandi áhrif á græðlinga salats (Lactucasativa var. capitata L) og vætukarsa (Lepidium sativum L.) og sannreyndi þannig jákvæð hormónaáhrif á lengingu kímstöngla samanborið við gibberellínsýra-meðferð. Bestu áhrifin sem líkja má við gibberellínsýru-meðferð var útþynning upp á 25,000 ppm og 15,000 ppm. Í samanburði voru engin skýr viðbrögð í vætukarsa plöntunum hvað varðar hömlun rótarvaxtar í kjölfar notkunar vatnsrofsefnis frá samræktinni samanborið við indóledikssýru meðferð. Möguleg tilvist áxín-líkra hormónaáhrifa var afsönnuð vegna mikils breytileika niðurstaðna.

Sponsor: 
  • University of Padua
Accepted: 
  • Jun 14, 2022
URI: 
  • http://hdl.handle.net/1946/41997


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Note: Andrea Durigon Master Thesis - University Centre of the Westfjords, Coastal and Marine Management master program