Molecules that can be metabolised by animals. Iron, for example, is extremely abundant in nature but as iron oxide (rust) which isn’t soluble in water. Iron is nonetheless vital for all animal respiration and plant photosynthesisMeaning how plants extract energy by absorbing water and using radiation from the Sun to combine it with carbon dioxide to create sugars. More. We rely on micro-organisms to fix the iron into forms that can be used and on animals, to concentrate it in the right time and place. In this book, when we refer to bioavailable, we are also referring to the energy in molecules / nutrientsEnergy and nutrients are the same thing. Plants capture energy from the Sun and store it in chemicals, via the process of photosynthesis. The excess greenery and waste that plants create, contain chemicals that animals can eat, in order to build their own bodies and reproduce. When a chemical is used this way, we call it a nutrient. As we More that is contained within biological systems and therefore, not “free energyThe energy of a system that is emitted as waste and is not part of ecosystem processes. There is always some free surplus energy as this creates the basis for evolution where new species exploit gaps in the ecosystem where free energy becomes available. Surplus energy can occur as a result of disruption or disturbance. When free surplus energy reaches More” in the atmosphere or oceans.
