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NGSS Performance Expectation: Use a mathematic representation to support claims for the cycling of matter and flow of energy in organisms in an ecosystem.
NC ESS 6th Grade: Conclude that good health of humans requires: monitoring the lithosphere, maintaining soil quality and stewardship.
NC EES 7th Grade: Conclude that good health of environments and organisms requires: monitoring the hydrosphere, water quality standards, methods of water treatment, maintaining safe water quality, stewardship.
NC ESS 8th Grade: Critique Conventional and Sustainable Agriculture and Aquaculture practices in terms of their environmental impacts.

Aquaponics-Farming of the Future by Frank Graff

Drive a couple hours south from Raleigh, out into the rolling hills, forests and farm fields of southwestern, North Carolina.  There, on the edge of the Uwharrie National Forest, you find the community of Norwood.

Lucky Clays is a farm and conference center near Norwood.  There’s a stone gate at the top of the winding drive, which passes through forests and fields, as well as past a barn and guest cottages before ending up in front of a large and rather rustic looking main building. 

But if you look closely, you also find hidden in the trees a large array of solar panels and a giant wind turbine. It makes you start to think this is a different type of farm and conference center.  Those thoughts are confirmed when you enter a futuristic  looking greenhouse down the dirt road from the main building.

 “This is our aquaponics operation,” explains Bradley Todd, the Aquaponics and Greenhouse Manager at Lucky Clays as he leads you into the building. “What we’re doing is incorporating hydroponics with aquaculture, so we’re using the water that is used in the fish system to grow plants.”

In a world where water is becoming scarce, you could say the future of farming is spread out in the large room before you.  Water is still required for this farming operation. But it needs only about one-tenth of the water used to grow vegetables in the ground.  That’s because an aquaponics farm is a closed system that recycles 99-point-five percent of its water.

“As the population grows, real estate shrinks, and the fish stocks in the ocean get depleted from overfishing and disease, we need to find a way to feed the population,” says Jean Paul Able, Lucky Clays Farm Manager. “This is a viable option because you can run this type of operation in the city, in a renovated building, or you can do it in a rural area like we’re doing.”

An aquaponics operation cleans and recycles the same water again and again for raising fish and growing vegetables.

The fish, tilapia, actually start their life in another building where they are raised until they are a few months old and a couple of inches long. They are then moved into giant blue tanks, which take up a corner of the main building.  The tanks are elevated because gravity keeps the entire process moving. The fish are fed several times a day. The fish are raised in the tanks for about a year. That’s how long it takes for them to grow to weigh roughly two pounds, which is the weight restaurants are asking for. The water is constantly circulating, which allows the fish to swim and the system to keep the water moving.

“Our filtration system follows gravity, so the water flows from the fish tanks through our bio filters,” explains Todd, who is showing me a handful of the tiny filters.  They look like small, round pieces of pasta. Bacteria form on the filters, and because the filters have a large surface area, they can handle quite a bit of bacteria.

That’s important, because the farm utilizes the bacteria to create the nitrogen cycle, which is what cleans the water and feeds the plants. One type of bacteria converts the ammonia that is in the water and comes from the fish waste into nitrates. The other bacterium then changes the nitrates into nitrates, which the plants use as food. Pumps keep the tiny filters circulating through the water and speed up the process.

“Because the specific gravity of fish food and fish waste is more than water, the solid waste is removed from the tanks as it settles to the bottom,” adds Todd.  “But just to be certain, the water is then pumped through filtration beds of rock which further cleans the water and removes any solids.”

The water is then used to soak a growth medium, in which the seeds are planted. The seeds spend about two weeks germinating and growing, until they are transferred to the main growth channels.  There are several long channels that run the length of the room.  The seeds float in cups, all anchored in giant frames that look like cup holders, stretching across the channels. The tiny plants say in the channels and grow. An aeration system, which runs along the bottom of the channels, keeps the water oxygenated.

The farm produces several types of lettuce, along with cilantro, basil and parsley. The plants move from through the water system from top to bottom in about six weeks. That’s less time than it takes for similar plants to grow in soil. The water that flows through the channels is then pumped back into the fish tanks, where it starts the process all over again.

“It is really a small ecosystem and just like an ecosystem in the real world, everything is tied together,” says Todd, who explains that closed system is what makes the farm so efficient, but also very fragile.

“Because it is a closed system, and the water is constantly circulating, if something happens in one area of the system it can effect everything else,” says Todd. “We take water quality samples every week and we constantly monitor the oxygen levels in the fish tank and the plant beds.”

The closed system also prevents the use of almost any chemical pesticide or fertilizer that is used in traditional farming, because any chemical that would be used on the plants would also affect the fish.

But the farm appears to be a success.

A new aquaculture facility is under construction nearby. The larger facility will produce 20 tons of fish, four tons of shrimp and 320-thousand units of produce per year.  It is scheduled to open in 2015. All of the fish and produce is destined for restaurants. The customer base is growing, along with the fish and the vegetables.

1. What are the stages of the nitrogen cycle depicted in this video? 
2. What happens if ammonium is not converted into nitrates and nitrates?
3. What are the stages of the carbon cycle depicted in this video?
4. What stage of which cycle holds the greatest risk for the farmer?
5. Conduct a SWOT (strengths, weaknesses, opportunities, threats) analysis of an aquaponic system.