Sneed et al. (1975) published the first description of an aquaponic system, which diverted
aquaculture effluent through plant growing troughs. The concept was that the nutrients in
aquaculture effluent could be put to good use to nourish and grow plants; meanwhile, potentially
polluted fish water would be cleaned up before being released into the environment. Plants
showed signs of nutrient deficiencies within a month, likely due to a couple of factors. In
hindsight, fertilizer nitrate nitrogen was 150 times lower than it is today. Furthermore, the
culture water was exposed to sunlight, which allowed microalgae to grow and further reduced
the available nutrients. At around the same time, Dr. John Todd and Nancy Jack Todd led
similar work at the New Alchemy Institute, which resulted in a natural wastewater treatment
system marketed as a ‘living machine.’