NUTRIENT WATER BALANCE
The biogeochemical cycles of major nutrients in aquaponics
The nitrogen cycle Nitrogen is an essential element for all living organisms and is the main nutrient of concern in aquaponics. It occurs in amino acids (parts of proteins), nucleic acids (DNA and RNA), and in the energy transfer molecule adenosine triphosphate (Pratt & Cornely 2014). As nitrogen occurs in many chemical forms, the nitrogen cycle is very complex (Figure 3). Figure 3: The general form of nitrogen cycle (Encyclopaedia Britannica)
· Aqu@teachPlant nutrition
Essential nutrient elements Plants require 16 (Resh 2013) or according to other sources 17 (Bittszansky et al. 2016) essential nutrient elements without which they are unable to complete a normal life cycle. Plants require essential nutrients for normal functioning and growth. A plant’s sufficiency range is the range of nutrient amount necessary to meet the plant’s nutritional needs and maximize growth. The width of this range depends on individual plant species and the particular nutrient.
· Aqu@teachNutrient supply in aquaponics
The chemical composition of system water in aquaponics is very complex. Besides a large array of dissolved ions, it contains organic substances resulting from the release of products of fish metabolism and feed digestion, as well as substances excreted by the plants. These substances are largely unknown, and their interactions can further influence the chemical composition and pH of aquaponic nutrient solutions. All this can exert manifold, but mostly yet unknown, effects on the nutrient uptake by plants, on fish health, and on microbial activity.
· Aqu@teachMacro- and micronutrients
The elements of the universe There are 92 naturally occurring elements on the Earth. Some are very well studied, some not at all: for example astatine (Bryson 2003). The problem is that some elements are very rare. For example, only 24.5 grams of francium occur at any time in the whole of the Earth’s crust. Only about 30 of the naturally occurring elements are widespread on Earth, and very few are important for life (Figure 1).
· Aqu@teach