Life cycle assessment on marine aquaponic production of shrimp, red orache, minutina and okahajiki.

Aquaponics is an integrated food production system that intensively produces a diverse array of seafood and specialty crops in one closed-loop system, which is a potential solution to global challenges of food security. While current aquaponics systems are commonly operated with freshwater, marine aquaponics is an emerging opportunity to grow saltwater animals and plants. Although marine aquaponics can reduce the dependence on freshwater for food production, its environmental sustainability has not been systematically studied. This paper presents the first life cycle assessment (LCA) on a marine aquaponic production system growing shrimp and three halophytes. The system assessed covered from shrimp larvae nursery to grow-out. The effects of salinity, carbon/nitrogen (C/N) ratio and shrimp-to-plant stocking density ratio of aquaponics on its midpoint and endpoint environmental impacts were evaluated using a functional unit based on the economic value of the four products. Electricity use for aquaponic operation was the environmental hotspot, contributing ∼90 % to all the midpoint impacts. The system produced higher environmental impacts when operated at higher salinity, but lower C/N ratio and stocking density. Replacing fossil fuel with wind power for electricity generation can decrease the environmental impacts by 95-99 %. Variation in the shrimp price can change the impacts by up to 62 %. This study provides a useful tool to help marine aquaponic farmers improve their production from an environmental perspective, and can serve as groundwork for further assessing more marine aquaponic systems with different animal-plant combinations.

Nutrient-efficient catfish-based aquaponics for producing lamb's lettuce at two light intensities.

BACKGROUND: Aquaponic systems are sustainable processes of managing water and nutrients for food production. An innovate nutrient-efficient catfish-based (Clarias gariepinus) aquaponics system was implemented for producing two cultivars of two leafy vegetables largely consumed worldwide: lamb's lettuce (Valerianella locusta var. Favor and Valerianella locusta var. de Hollande) and arugula (Eruca vesicaria var. sativa and Eruca sativa). Different growing treatments (4 × 2 factorial design) were applied to plants of each cultivar, grown at two light intensities (120 and 400 µmol m-2 s-1). During growth, several morphological characteristics (root length, plant height, leaf number, foliage diameter and biggest leaf length) were measured. At harvest, plants were weighed and examined qualitatively in terms of greenness and health status. Additionally, leaf extracts were obtained and used to determine total phenolic contents, antioxidant capacities, and levels of cytotoxicity to Caco-2 intestinal model cells. RESULTS: After a 5-week growth period, both lamb's lettuce cultivars presented high levels of greenness and health status, at both light intensities, particularly the var. de Hollande that also showed higher average performance in terms of plant morphology. In turn, arugula cultivars showed lower levels of greenness and health status, especially the cultivar E. vesicaria var. sativa submitted to direct sunlight during growth. In addition, plant specimens submitted to higher levels of light intensity showed higher contents in antioxidants/polyphenols. Cultivars with a higher content in antioxidants/polyphenols led to higher Caco-2 cell viability. CONCLUSION: For successful industrial implementation of the aquaponics technology, different and optimized acclimatizing conditions must be applied to different plant species and cultivars. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Integration of down-flow hanging sponge reactor to oreochromis niloticus - Brassica oleracea aquaponics system.

Aquaponics is a promising solution for addressing food security concerns. Nonetheless, an effective water-purification system is necessary to achieve high and stable yields of fish and vegetables. This study aimed to evaluate the nitrification and oxygen transfer performance of a laboratory-scale down-flow hanging sponge (DHS) reactor with a Brassica oleracea aquaponics system to treat water in an Oreochromis niloticus closed-aquaculture system. The DHS reactor showed a higher oxygen transfer coefficient (KLa) than the conventional aerator and provided an adequate dissolved oxygen (DO) concentration of approximately 5.5 mg/L essential for O. niloticus growth throughout the experimental period. The evaluated DHS-based aquaponic system maintained high water quality in an aquaculture tank, with a survival rate of 97%. The O. niloticusgrew at a low feed conversion ratio of 1.5-2.1 and a low feeding rate of 0.5% at high stocking densities of 17.5-22.2 kg-fish-weight/m3. 16S rRNA gene sequencing indicated that the DHS sponge carrier effectively retained nitrifying bacteria such as Nitrosomonas and Nitrospira. This study demonstrated that the DHS reactor provided a high DO concentration and that a simultaneous DHS reactor with a hydroponic tank provided a low-cost aquaponic system that could be applied for food production in the aquaculture industry.

A Modularized IoT Monitoring System with Edge-Computing for Aquaponics.

Aquaponics is a green and efficient agricultural production model that combines aquaculture and vegetable cultivation. It is worth looking into optimizing the proportion of fish and plants to improve the quality and yield. However, there is little non-destructive monitoring of plant growth in aquaponics monitoring systems currently. In this paper, based on the Internet of Things technologies, a monitoring system is designed with miniaturization, modularization, and low-cost features for cultivation-breeding ratio research. The system can realize remote monitoring and intelligent control of parameters needed to keep fish and plants under optimal conditions. First, a 32-bit chip is used as the Microcontroller Unit to develop the intelligent sensing unit, which can realize 16 different data acquisitions as stand-alone extensible modules. Second, to achieve plant data acquisition and upload, the Raspberry Pi embedded with image processing algorithms is introduced to realize edge-computing. Finally, all the collected data is stored in the Ali-cloud through Wi-Fi and a WeChat Mini Program is designed to display data and control devices. The results show that there is no packet loss within 90 m for wireless transmission, and the error rate of environment parameters is limited to 5%. It was proven that the system is intelligent, flexible, low-cost, and stable which is suitable for small-scale aquaponics well.

Digital Twinning of Hydroponic Grow Beds in Intelligent Aquaponic Systems.

The use of automation, Internet-of-Things (IoT), and smart technologies is being rapidly introduced into the development of agriculture. Technologies such as sensing, remote monitoring, and predictive tools have been used with the purpose of enhancing agriculture processes, aquaponics among them, and improving the quality of the products. Digital twinning enables the testing and implementing of improvements in the physical component through the implementation of computational tools in a 'twin' virtual environment. This paper presents a framework for the development of a digital twin for an aquaponic system. This framework is validated by developing a digital twin for the grow beds of an aquaponics system for real-time monitoring parameters, namely pH, electroconductivity, water temperature, relative humidity, air temperature, and light intensity, and supports the use of artificial intelligent techniques to, for example, predict the growth rate and fresh weight of the growing crops. The digital twin presented is based on IoT technology, databases, a centralized control of the system, and a virtual interface that allows users to have feedback control of the system while visualizing the state of the aquaponic system in real time.

Water IoT Monitoring System for Aquaponics Health and Fishery Applications.

Aquaponic health is a very important in the food industry field, as currently there is a huge amount of fishing farms, and the demands are growing in the whole world. This work examines the process of developing an innovative aquaponics health monitoring system that incorporates high-tech back-end innovation sensors to examine fish and crop health and a data analytics framework with a low-tech front-end approach to feedback actions to farmers. The developed system improves the state-of-the-art in terms of aquaponics life cycle monitoring metrics and communication technologies, and the energy consumption has been reduced to make a sustainable system.

Effect of potassium supplementation on osmoregulatory and stress response of Pangasianodon hypophthalmus (Sauvage, 1878) with Spinacia oleracea L. in aquaponics.

This study evaluated the effect of different potassium supplementation dosages on the physiological responses of Pangasianodon hypophthalmus reared in an aquaponic system with Spinacia oleracea L. for 60 days. The system comprised of a rectangular fish tank of 168 l capacity (water volume = 100 l) with nutrient film technique (NFT)-based hydroponic component with fish to plant ratio of 2.8 kg m-3 : 28 plants m-2 in all the treatments. The osmoregulatory and stress parameters of P. hypophthalmus at four different potassium dosages of T1 (90 mg l-1 ), T2 (120 mg l-1 ), T3 (150 mg l-1 ) and T4 (180 mg l-1 ) were compared with C (control, 0 mg l-1 ) to examine the potassium level to be applied to aquaponics. The water quality parameters and fish production were found to have no adverse impact due to potassium supplementation. The spinach yield during two harvests, i.e., before and after potassium supplementation, revealed that the yield was significantly higher (P < 0.05) after supplementation with the highest yield in T3 and T4. The osmoregulatory parameters such as plasma osmolality, Na+ , K+ ATPase activity in gill and plasma ionic profile (Cl- , Ca2+ and Na+ ) showed an insignificant variation (P > 0.05) between control and treatments except for higher plasma potassium concentration (1.98 ± 0.19 mmol l-1 ) in T4. The stress and antioxidant enzyme analysis exhibited significantly higher plasma glucose and superoxide dismutase (SOD) activity in gill and liver in T4, whereas cortisol and catalase showed an insignificant difference (P > 0.05). The experimental findings demonstrated that the potassium dosage up to 150 mg l-1 could be suggested as optimum for P. hypophthalmus and spinach aquaponics without impairing the health and oxidative status of P. hypophthalmus.

Phytochemicals and quality level of food plants grown in an aquaponics system.

BACKGROUND: Beyond nutrition, fruits and vegetables can be considered as natural sources of bioactive molecules, for which beneficial effects on human health are widely recognised. To improve food quality, soilless growing systems could represent a good strategy for promoting a sustainable food production chain, although the nutritional and nutraceutical properties of their products should be investigated in depth. The main quality traits and the volatile and non-volatile secondary metabolites of Solanum lycopersicum L., Petroselinum crispum (Mill.) Fuss and Ocimun basilicum L. grown in an aquaponics system and in organic farming were quantified and compared. RESULTS: On a fresh basis, soil-grown P. crispum and O. basilicum showed significantly higher total phenolics and antioxidant activity compared to aquaponic crops, whereas, on a dry basis, both plants showed opposite results. Soil-grown S. lycopersicum was significantly richer in total phenolics, whereas the aquaponic type showed a higher antioxidant activity. Aquaponics induced the accumulation of resveratrol in P. crispum, rosmarinic acid and myricetin in O. basilicum, and lycopene in S. lycopersicum. Among the volatile compounds, in O. basilicum, linalool was the main constituent in both treatments, whereas τ-cadinol represented the second constituent in aquaponic crops. The volatile profiles of P. crispum did not differ significantly between the two cultivation methods. CONCLUSION: The overall quality of organic and aquaponics cultures appeared to be comparable. The results showed that aquaponic farming method can be an innovative, rapid and sustainable way of producing quality food. © 2021 Society of Chemical Industry.

Environmental parameters and microbial community profiles as indication towards microbial activities and diversity in aquaponic system compartments.

BACKGROUND: An aquaponic system couples cultivation of plants and fish in the same aqueous medium. The system consists of interconnected compartments for fish rearing and plant production, as well as for water filtration, with all compartments hosting diverse microbial communities, which interact within the system. Due to the design, function and operation mode of the individual compartments, each of them exhibits unique biotic and abiotic conditions. Elucidating how these conditions shape microbial communities is useful in understanding how these compartments may affect the quality of the water, in which plants and fish are cultured. RESULTS: We investigated the possible relationships between microbial communities from biofilms and water quality parameters in different compartments of the aquaponic system. Biofilm samples were analyzed by total community profiling for bacterial and archaeal communities. The results implied that the oxygen levels could largely explain the main differences in abiotic parameters and microbial communities in each compartment of the system. Aerobic system compartments are highly biodiverse and work mostly as a nitrifying biofilter, whereas biofilms in the anaerobic compartments contain a less diverse community. Finally, the part of the system connecting the aerobic and anaerobic processes showed common conditions where both aerobic and anaerobic processes were observed. CONCLUSION: Different predicted microbial activities for each compartment were found to be supported by the abiotic parameters, of which the oxygen saturation, total organic carbon and total nitrogen differentiated clearly between samples from the main aerobic loop and the anaerobic compartments. The latter was also confirmed using microbial community profile analysis.

Comparison of two commercial recirculated aquacultural systems and their microbial potential in plant disease suppression.

BACKGROUND: Aquaponics are food production systems advocated for food security and health. Their sustainability from a nutritional and plant health perspective is, however, a significant challenge. Recirculated aquaculture systems (RAS) form a major part of aquaponic systems, but knowledge about their microbial potential to benefit plant growth and plant health is limited. The current study tested if the diversity and function of microbial communities in two commercial RAS were specific to the fish species used (Tilapia or Clarias) and sampling site (fish tanks and wastewaters), and whether they confer benefits to plants and have in vitro antagonistic potential towards plant pathogens. RESULTS: Microbial diversity and composition was found to be dependent on fish species and sample site. The Tilapia RAS hosted higher bacterial diversity than the Clarias RAS; but the later hosted higher fungal diversity. Both Tilapia and Clarias RAS hosted bacterial and fungal communities that promoted plant growth, inhibited plant pathogens and encouraged biodegradation. The production of extracellular enzymes, related to nutrient availability and pathogen control, by bacterial strains isolated from the Tilapia and Clarias systems, makes them a promising tool in aquaponics and in their system design. CONCLUSIONS: This study explored the microbial diversity and potential of the commercial RAS with either Tilapia or Clarias as a tool to benefit the aquaponic system with respect to plant growth promotion and control of plant diseases.

Development of an aquaponics microbial inoculum for efficient nitrification at acidic pH.

Maintaining an optimal pH that simultaneously supports plants, fish, and nitrifying microorganisms is a challenge in recirculating aquaponics systems as nitrification is optimal at a slightly alkaline pH and plant growth is optimal at a slightly acidic pH. Freshwater fish tolerate pH > 5.5. Our aim was to adapt a microbial inoculum for a recirculating aquaponics system from an operational pH of 7.6 to 5.6, compare nitrification activity and production of N2O, and describe changes in the adapted versus unadapted microbial communities. Four adaptation strategies were tested; our results indicated that a gradual reduction from pH 7.6 to 5.6, along with a gradual reduction followed by a gradual return of available ammonium, was the best strategy resulting in retention of 81% nitrification activity at pH 5.6 compared to pH 7.6. 16S rRNA gene amplicon sequencing and qPCR enumeration of nitrification-related genes showed that the composition of pH 5.6 adapted microbial communities from all four adaptation strategies was similar to one another and distinct from those operating at pH 7.6, with enrichment of comammox clade B bacteria over ammonia-oxidizing bacteria and thaumarchaeota. N2O production of the pH 5.6 adapted microbial communities was below detection in all adaptation experiments, likely due to the increased proportion of comammox bacteria. Aquaponics biofilters enriched with comammox bacteria and adapted to function at pH 5.6 can be a desirable inoculum for freshwater recirculating aquaponics systems to retain nitrification activity and improve crop yields.Key points• Microbial communities adapted from pH 7.6 to pH 5.6 retained 81% nitrification activity.• Microbial communities adapted from pH 7.6 to pH 5.6 were enriched in comammox bacteria.• Comammox-enriched microbial communities did not produce N2 O.

Evaluation of Escherichia coli and coliforms in aquaponic water for produce irrigation.

The FDA Produce Safety Rule states that water used for irrigation purposes, likely to come into contact with the edible portion of fruit and vegetables, must not exceed a defined limit of Escherichia coli populations. Although aquaponics has not been included in this guideline, it is worth investigating to establish a baseline for facilities to reference in produce production. Two microbial assays were performed, one a decoupled media-based aquaponics system over one year and another on a decoupled nutrient film technique (NFT) aquaponics system over 16 days. Water was sampled from each system over time to analyze changes of E. coli and coliforms. The geometric mean (GM) and statistical threshold variable (STV) were calculated based on E. coli populations from the irrigation source in each system. From the first experiment, it was determined, based on the FDA Produce Safety Rule, that E. coli must be monitored more closely from June to January as they were above the advised limit. The second experiment determined that E. coli and coliforms in the water significantly decreased over 16 days. Water should be held for 8 d and up to 16 d to reduce the likelihood of foodborne pathogens to contaminate produce.

Combined SPRi Sensor for Simultaneous Detection of Nitrate and Ammonium in Wastewater.

Water pollution is a serious problem in modern society. Agriculture, being responsible for the discharge of agrochemicals, organic matter, or drug residues, produces a huge amount of wastewater. Aquaponics has the potential to reduce both water consumption and the impact of water pollution on fish farming and plant production. In the aquatic environment, inorganic nitrogen is mostly present in the form of nitrate and ammonium ions. Nitrate, as a final product of ammonia mineralization, is the most common chemical contaminant in aquifers around the world. For continuous monitoring of nitrogen compounds in wastewater, we propose a sensor for the simultaneous detection of nitrate and ammonium. A surface plasmon resonance imaging method with enzyme-mediated detection was used. Active layers of nitrate reductase and glutamine synthetase were created on the gold surface of a biochip and tested for the sensing of nitrate and ammonium in water from an aquaponic system. The proposed sensor was applied in water samples with a concentration of NO3- and NH4+ in a range between 24-780 mg·L-1 and 0.26-120 mg·L-1, respectively, with minimal pretreatment of a sample by its dilution with a buffer prior to contact on a biochip surface.

Consumer preferences for aquaponics: A comparative analysis of Australia and Israel.

Aquaponics, the combined rearing of fish and hydroponic horticulture, has great potential for sustainable food production. Despite increasing research and investments in commercial scale systems, aquaponics is not yet a successful industry and most businesses report negative returns. Aquaponic produce is thought to contain added value to the consumer, and the environment. As most consumers are unaware of aquaponics and their benefits, little is known of its potential market. The present study addresses this gap by analysing willingness to consume aquaponic produce at different price levels in Israel and Australia. We used econometric tools to study the effects of pricing and other factors on revenues in each country. Cluster analysis was used to define groups of potential consumers. The results indicate that 17-30% of the population in both Israel and Australia would prefer to consume aquaponic produce once informed of their added value. Revenues at a given premium would be higher in Israel than in Australia, and higher for a leafy green, than for fish. Different segments of the population differed in their willingness to consume aquaponic produce, as well as in their stated motivations when purchasing food. Conclusions highlight the importance of case-specific research on consumer preferences and economic considerations preceding commercial investment in aquaponics.

Understanding nutrient throughput of operational RAS farm effluents to support semi-commercial aquaponics: Easy upgrade possible beyond controversies.

The present research attempted to address a key industry-level question amidst Recirculating Aquaculture System (RAS) waste throughput and aquaponics limitations controversies. Nutrient throughput of three operational RAS farms with progressive size proportions (16, 130, 1400 m3), aquaculture intensity (24, 62, 86 kg stock m-3) were studied. Results suggest - daily total efflux and potency of nutrients in effluents should not be generalized, extreme variability exists. Consistencies of nutrients in wastewater (except N, Ca and Na) are higher than in sludge. Asynchrony between patterns of nutrient loading and effluent nutrient concentrations exist for secondary macronutrients and micronutrients (S, Mg, Fe, Cu, Zn, B, Mo). Macronutrient output generally increases with increasing farm size and culture intensity but same cannot be said for micronutrients. Deficiency in wastewater can be completely masked using raw or mineralized sludge, usually containing 3-17 times higher nutrient concentrations. RAS effluents (wastewater and sludge combined) contain adequate N, P, Mg, Ca, S, Fe, Zn, Cu, Ni to meet most aquaponic crop needs. K is generally deficient requiring a full-fledged fertilization. Micronutrients B, Mo are partly sufficient and can be easily ameliorated by increasing sludge release. The presumption surrounding 'definite' phyto-toxic Na levels in RAS effluents should be reconsidered - practical solutions available too. No threat of heavy metal accumulation or discharge was observed. Most of the 'well-known' operational influences failed to show any significant predictable power in deciding nutrient throughput from RAS systems. Calibration of nutrient output from operational RAS farms may be primarily focused around six predictors we identified. Despite inherent complexity of effluents, the conversion of RAS farms to semi-commercial aquaponics should not be deterred by nutrient insufficiency or nutrient safety arguments. Incentivizing RAS farm wastes through semi-commercial aquaponics should be encouraged - sufficient and safe nutrients are available.

Effects of hydraulic retention time on the performance of algal-bacterial-based aquaponics (AA): focusing on nitrogen and oxygen distribution.

The effects of hydraulic retention time (HRT) on the performance of algal-bacterial-based aquaponics (AA) were investigated in this study. Both the highest fish growth and algal biomass increase were observed in the AA system at 2-day HRT, resulting in the highest nitrogen utilization efficiency (NUE) (39.28%) in this microcosm. On the contrary, ammonia oxidation bacteria (AOB) abundance at 4-day HRT was approximately ten times higher than that at 2-day HRT, since longer HRT would benefit bacterial growth. The 15N labeling study showed that microalgae assimilation was the main pathway of NH4+ removal in the AA system, and oxygen produced by microalgae could in situ support complete nitrification, thus leading to much lower NH4+ concentrations at 2-day HRT. Accordingly, better water quality was achieved at 2-day HRT. Considering all the factors, HRT of 2-day was considered to be optimal for the AA system.

Amyloodinum ocellatum in Dicentrarchus labrax: Study of infection in salt water and freshwater aquaponics.

This investigation is aimed to improve the knowledge on the physiological alterations occurring at morphological and molecular level in European sea bass naturally infected by A. ocellatum and reared at different salinities. European sea bass juveniles (Dicentrarchus labrax) weighing 20 ± 0.5 g were divided in three aquaponics systems: CTRL, reared at 20 ppt salinity; AFI, reared in freshwater (0 ppt) and infected with the dinoflagellate Amyloodinium ocellatum; ASI, reared at 20 ppt salinity and infected with A. ocellatum. Beta vulgaris plants were introduced in each of the aquaponic systems. Temperature was increased 1 °C every second day from 18 to 25 °C during the experiment. At the end of the trial, liver, brain, intestine and gills were sampled for molecular and histological analyses. A. ocellatum affected D. labrax growth (insulin-like growth factor I, IGF-I) and appetite (Neuropeptide Y, NPY) signals in ASI. Immune system was activated in ASI by the presence of parasites by producing higher levels of Interleukin-1 (IL-1) and Tumor Necrosis Factor α (TNFα). Peroxisome proliferator-activated receptor α (PPAR α), codifying for a protein involved in lipid metabolism, was upregulated in ASI because of the necessity to produce energy to maintain homeostasis. On the contrary, A. ocellatum did not cause signs of infection in AFI as confirmed by gene expression and histological analysis, that were similar to CTRL. However, in freshwater reared fish, a modification of lipid metabolism was observed through a reduction in PPARα gene expression and hepatic lipid content.

Insect pests and natural enemies associated with lettuce Lactuca sativa L. (Asteraceae) in an aquaponics system.

Although food is produced in aquaponics systems worldwide, no information is available on the occurrence of insect pests and natural enemies in aquaponic lettuce, Lactuca sativa L. In this study, a survey was carried out in an aquaponic system combining lettuce with lambari, Astyanax altiparanae (Garutti & Briski), aiming to determine the insect pests and natural enemies associated with this system. We also determined the predominant insect species and the effect of meteorological factors on their populations. Insect abundance was estimated by visual sampling during 13 cultivation cycles, totaling 27 sampling dates. The meteorological factors considered were air temperature and relative humidity, and their effects were determined using the Pearson correlation. The thrips Frankliniella schultzei (Trybom) and Caliothrips phaseoli (Hood) and the aphid Aphis spiraecola (Patch) predominated. Ambient temperature and relative humidity were essential factors affecting C. phaseoli and F. schultzei. The natural enemies found on the lettuce plants were the thrips Franklinothrips vespiformis (Crawford) and Stomatothrips angustipennis (Hood) and the ladybugs Cycloneda sanguinea L., Eriopis connexa (Germar), and Hippodamia convergens (Guérin-Méneville). These results constitute the first step for a lettuce-integrated pest-management program in aquaponics systems.

Runoff of foliar-applied natural fungicides in aquaponics: Implications for fish and nitrification.

Aquaponics is a method of producing food in a sustainable manner through the integration of aquaculture and hydroponics, which allows simultaneous cultivation of fish and economic crops. The use of natural fungicides are crucial to the sustainable control of diseases in aquaponics. We assessed the potential impacts of natural fungicides, such as clove oil and lecithin, as well as a synthetic fungicide, tebuconazole, following foliar application in aquaponics. This study examined the runoff rates of the fungicides in decoupled aquaponics, and the subsequent effects of the runoffs on nitrification processes and Nile tilapia (Oreochromis niloticus). The runoffs of the foliar-applied fungicides, clove oil, lecithin, and tebuconazole, were detected in aquaponics water at a percentage runoff rate of 0.3 %, 2.3 %, and 0.3-0.8 % respectively. In the biofilter, lecithin altered the ammonium levels by increasing ammonium-nitrogen levels by 7 mg L-1, 6 h post application. Clove oil, on the other hand, showed no significant effect on ammonium, nitrite, and nitrate-nitrogen. Similarly, the toxicity test showed that eugenol had no significant effects on the hematological, biochemical and antioxidative activities of O. niloticus. Conversely, tebuconazole exhibited significant and persistent effects on various biochemical parameters, including lactate, albumin, and total protein, as well as hematological parameters like hemoglobin and MCH. The use of lecithin and tebuconazole should only be limited to decoupled aquaponics.

Ciliate diversity and growth rates in experimental recirculating aquaculture and aquaponics systems using microscopy.

The function of recirculating aquaculture systems (RAS) relies on microbial communities, which convert toxic, fish-excreted ammonia into substances that can provide nutrients to plants as in the case of aquaponics systems. In the present study, heterotrophic protist communities of experimental sea water RAS and freshwater aquaponics systems were investigated using microscopy to characterize their diversity, natural abundance, and potential growth rates. Heterotrophic protist abundance was low (732 ± 21 to 5451 ± 118 ciliates L-1 and 58 ± 8 to 147 ± 18 nanoflagellates mL-1 in the aquaponics system and 78 ± 28 to 203 ± 48 ciliates L-1 in the RAS), which is in line with values typically reported for rivers. In the aquaponics system, ciliates grew faster in the fish rearing tanks (1.9 ± 0.01 to 1.21 ± 0.03 d-1 compared to 0.54 ± 0.03 to 0.79 ± 0.05 d-1 in the other compartments), while heterotrophic nanoflagellates grew slower in drain tanks downstream of the hydroponics compartment (0.5 ± 0.3 to 1.37 ± 0.05 d-1 and 4.09 ± 0.11 d-1 to 6.03 ± 0.34 d-1in the other compartments). Results indicated distinct niches and reduced microeukaryotic diversity at the end of the system's operation cycle.