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Aquaponics is a method of raising fish and plants together for optimum benefits. It combines hydroponics, which is a process for growing agricultural and ornamental plants in fertilizer and water — with or without a growing medium such as sand or peat moss — and aquaculture, which is a technical term for commercial fish farming. Aquaponics eliminates many of the environmental issues seen in traditional farming and aquaculture and provides local sources for organic food.
Land-based agriculture can be hard on the environment. Crops often use nitrogen-based fertilizers. The fertilizers seep into ground water and run into rivers and streams, where they foster the growth of aquatic plant life and algae. Excessive algae growth strips oxygen from the water and chokes out animal life, creating dead zones in the water.
At the same time, aquaculture can be equally dangerous to the environment. Fish leave uneaten food in the water and produce bodily waste. Both of these processes create a buildup of ammonia, which fish growers then pump out into rivers and streams, encouraging the growth of excessive amounts of algae. Dying algal blooms deplete the environment of oxygen and create toxins that kill marine life.
Aquaponics cancels out these two problems. In the simplest form of aquaponics, growers cultivate fish in ponds or fish tanks; the tanks are equipped with pumps that send the water through plant beds filled with a medium such as gravel or clay. The water filters through the medium, and the plants extract the nutrients from the fish waste in the water. The purified water then filters back into the fish tank. Deep-water culture, another form of aquaponics, floats the plants on the surface of the water, while the nutrient film technique involves growing vegetables in plastic holders designed to allow their roots to come in contact with the water to extract nutrients.
Growers can choose a number of types of fish and plants. Ornamental fish species such as koi, goldfish and other types of carp work well. Many growers prefer edible varieties such as trout, Murray cod, perch and tilapia. Several commonly grown vegetables include eggplant, cabbage, lettuce, tomato and peppers.
Aquaponics is beneficial to the environment, because it is essentially a self-sustaining, self-balancing system. The fish provide the plants with nutrients, and the plants provide the fish with clean water. It holds potential for future use, particularly in dry areas with limited water resources, because it re-uses and recycles water. It helps small farmers who cannot afford to pay for expensive chemical fertilizers, and it encourages local, environmentally friendly farming.
It does have potential drawbacks, though. Getting started in aquaponics can be expensive, because there's a lot of equipment to buy. A system that depends on manmade energy also may be trading one environmental disadvantage for another. The options for crops — both fish and plant — are practically endless, and getting one that provides maximum yield and efficiency may take some trial and error.