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Interdisciplinary Research for Bio-integrated Agro-Aquaculture Systems

Aquaponics

Aquaponics

1. Concept and Working Principle

Aquaponics is an integrated food production model that combines aquaculture (fish farming) and hydroponics (soilless plant cultivation) in a closed-loop system. It is based on a symbiotic relationship between fish, plants, and microorganisms. Fish release nutrient-rich waste (mainly in the form of ammonia), which is converted by nitrifying bacteria into nitrites and nitrates usable by plants. The plants absorb these nutrients, purifying the water, which is then recirculated back to the fish tanks. This natural recycling of water and nutrients creates a zero-waste, resource-efficient production system (Kargın & Bilgüven, 2018; Meyer et al., 2025).

Through this integration, aquaponics minimizes freshwater consumption, eliminates the need for chemical fertilizers, and increases overall yield, making it a sustainable and eco-friendly production technology that supports food security, especially in water-scarce regions.

2. System Components and Structure

An aquaponic system consists of:

  • Aquaculture unit: where fish or crustaceans are raised.
  • Hydroponic unit: where plants grow in nutrient-rich recirculated water.
  • Biofiltration system: where beneficial bacteria (mainly Nitrosomonas and Nitrobacter) convert toxic ammonia into nitrate.
  • Mechanical filtration unit: removes uneaten feed and solid waste.
  • Water circulation unit: pumps water between tanks, maintaining oxygen and pH balance (6.8–7.0 range) (Somerville et al., 2014).

Commonly used fish species include tilapia, carp, catfish, and rainbow trout, while popular plants are lettuce, basil, mint, tomato, and leafy greens. The selection of compatible species is essential for maintaining balance between nutrient production and uptake (Somerville et al., 2014; Özçiçek, 2023a; Özçiçek,2023b).

3. Biological Components of Aquaponics

The biotic elements (fish, plants, and bacteria) form the living core of the system:

  • Fish: act as nutrient providers; species are chosen based on temperature tolerance, market demand, and adaptability. Tilapia (Oreochromis niloticus) is often favored for its resilience and high growth rate (Gökvardar et al., 2022).
  • Plants: serve as biofilters, removing nitrogen and phosphorus compounds from the water. Leafy vegetables and herbs thrive due to their high nitrogen demand and short growth cycles.
  • Bacteria: ensure nutrient transformation. Nitrifying bacteria convert ammonia to nitrate, while phosphate-solubilizing bacteria (e.g., Bacillus, Pseudomonas, Lysinibacillus) make phosphorus bioavailable to plants (Joyce et al., 2019; Prastowo et al., 2024).

This tripartite interaction maintains water quality and allows nutrient recycling of nitrogen, phosphorus, and carbon within the system.

4. Main Aquaponic Techniques

Aquaponic systems are classified by plant bed type and water flow design:

  • Nutrient Film Technique (NFT):
    A thin film of water containing dissolved nutrients flows through sloped PVC channels, contacting plant roots. It offers efficient water and oxygen delivery but requires careful flow control and regular filtration to prevent clogging. Ideal for herbs and leafy greens.
  • Media-Based Technique (Grow-Bed System):
    Plants grow in a substrate (e.g., gravel, perlite, expanded clay). The medium provides support and acts as a bio-mechanical filter, promoting microbial activity. This system mimics natural soil processes and is suited for mixed crop types but can be heavy and labor-intensive.
  • Floating Raft or Deep Water Culture (DWC):
    Plants are placed on floating panels (usually Styrofoam) with roots suspended in oxygenated water. The method is low-cost, easy to manage, and ideal for fast-growing crops like lettuce and spinach.

Each technique has distinct advantages in terms of cost, maintenance, and plant type. NFT and DWC systems are more efficient for large-scale operations, while media beds are suitable for small-scale or educational setups (Somerville et al., 2014; Maucieri et al., 2019).

5. Ecological and Environmental Processes

Aquaponics naturally integrates biogeochemical cycles within its design:

  • Nitrogen Cycle: Converts toxic ammonia to nitrate via nitrifying bacteria, allowing safe nutrient uptake by plants.
  • Phosphorus Cycle: Organic phosphorus from fish feed and waste is mineralized by microorganisms into phosphate for plant use.
  • Carbon Cycle: CO₂ from fish and microbial respiration is absorbed by plants during photosynthesis, releasing oxygen that sustains aquatic organisms.

These interconnected cycles enable self-regulation and resilience, reducing nutrient discharge and promoting circular resource use (Espinal & Matulić, 2019).

6. Advantages and Challenges

Advantages:

  • 90–95% lower water consumption compared to conventional agriculture.
  • No chemical fertilizers or soil required.
  • Continuous nutrient recycling and minimal waste discharge.
  • Potential for urban and rooftop farming applications.
  • Year-round production and high space efficiency.

Challenges:

  • High initial setup cost and technical expertise requirements.
  • Dependence on stable power supply and water quality control.
  • Need for balanced fish–plant–bacteria interaction to avoid toxicity or nutrient deficiencies.
  • Limited large-scale commercial adoption in some regions.

7. Sustainability Perspective

Aquaponics supports multiple UN Sustainable Development Goals (SDGs), including:

  • SDG 2 – Zero Hunger: promoting food security.
  • SDG 6 – Clean Water and Sanitation: through water reuse and waste minimization.
  • SDG 12 – Responsible Consumption and Production: via circular nutrient use.
  • SDG 13 – Climate Action: by reducing emissions linked to fertilizer and water use.
  • SDG 14 – Life Below Water: by preventing nutrient pollution in aquatic ecosystems.

As a closed-loop, low-impact production model, aquaponics represents a key innovation for future sustainable food systems.

References

Espinal, C.A. & Matulić, D. 2019. Recirculating Aquaculture Technologies. In: Goddek, S., Joyce, A., Kotzen, B., Burnell, G.M. (Eds.), Aquaponics Food Production Systems: Combined Aquaculture and Hydroponic Production Technologies for the Future. Springer International Publishing, Cham, pp. 35-76.

Gökvardar, A., Özden, O., Serezli, R. (2022). Su Ürünleri Yetiştiriciliğinde Sürdürülebilir Uygulamalar: Akuaponik Sistem Yaklaşımları. In B. Karataş (Ed.), Su Ürünlerinde Modern Perspektifler (Bölüm 2, ss. 25-58). Ankara: Iksad Publications.

Joyce, A., Timmons, M., Goddek, S., Pentz, T., 2019. Bacterial Relationships in Aquaponics: New Research Directions. In: Goddek, S., Joyce, A., Kotzen, B., Burnell, G.M. (Eds.), Aquaponics Food Production Systems: Combined Aquaculture and Hydroponic Production Technologies for the Future. Springer International Publishing, Cham, pp. 145-161. https://doi.org/10.1007/978-3-030-15943-6_2, 978- 3-030-15943-6.

Kargın, H., & Bilgüven, M. 2018. Akuakültürde Akuaponik Sistemler ve Önemi. Bursa Uludağ Üniversitesi Ziraat Fakültesi Dergisi, 32(2), 159-173.

Maucieri, C., Nicoletto, C., Van Os, E., Anseeuw, D., Havermaet,R.V., Junge,R.,2019. Hydroponic Technologies. In: Goddek, S., Joyce, A., Kotzen, B., Burnell, G.M. (Eds.), Aquaponics Food Production Systems: Combined Aquaculture and Hydroponic Production Technologies for the Future. Springer International Publishing, Cham, pp. 145-161. https://doi.org/10.1007/978-3-030-15943-6_2, 978- 3-030-15943-6

Meyer, J., Weisstein, F.L., Kershaw, J., Neves, K. 2025. A multi-method approach to assessing consumer acceptance of sustainable aquaponics. Aquaculture, 596, 741764,  https://doi.org/10.1016/j.aquaculture.2024.741764

Özçiçek, E. (2023a). Akuaponik Sistemlerde Önemli Balık Türleri. In H. Y. Çoğun (Ed.), Su Ürünlerinde Yeni Gelişmeler (Bölüm 2, ss. 47-62). Ankara: BİDGE Yayınları

Özçiçek, E. (2023b). Akuaponik Sistemlerde Önemli Bitki Türleri. In H. Y. Çoğun (Ed.), Su Ürünlerinde Yeni Gelişmeler (Bölüm 2, ss. 117-131). Ankara: BİDGE Yayınları

Prastowo, B.W., Lestari, I.P., Agustini, N.W.S, Priadi, D., Haryati, Y.,  Jufri, A., Deswina, P. Adi, E.B.M., Zulkarnaen,I., 2024. Bacterial communities in aquaponic systems: Insights from red onion hydroponics and koi biological filters, Case Studies in Chemical and Environmental Engineering, 10, 100968.  https://doi.org/10.1016/j.cscee.2024.100968.

Somerville, C., Cohen, M., Pantanella, E., Stankus, A. & Lovatelli, A. (2014). Small-scale aquaponic food production.Integrated fish and plant farming. Rome: FAO Fisheries and Aquaculture Technical Paper. No. 589.