In order to understand the cycle of life, the conservation of energy, even the balance of infinity and void and the beginning of realisation that infinity is void, I find looking deeper into the event of death and decay quite important.
In nature, biological, chemical, geological and spiritual forces are constantly at work, transforming energies (in matter both living and non-living). Whether we call something growth or decay is again a perception.
In scientific terms, nutrients get recycled in nature, from dead matter to provide for growth of living matter. The bacteria, fungi and small invertebrates (snails, beetles, worms etc) are crucial in this cycle. Bacteria can feed only on exposed surfaces of organic matter. Hence, bacterial growth is slow until the invertebrates chew their food and fragment the matter into smaller bits. The fungi however can extend their hyphae to penetrate through matter. Also fungi have evolved over time and have an enzyme to break down lignin, a chemical complex in the plant body (wood). Thus fungi are more effective in decomposing plant matter. It can be said that bacteria are the primary decomposers for most animal matter while fungi are the primary decomposers for most plant matter.
Decomposition of plant material is usually odourless, and takes place in the presence of air (oxygen in particular). When people make compost heaps in their garden, they are utilising the same process, which is concentrated and accelerated by piling the dead material together in a compost heap, where the heat that is generated speeds up the process of decay.
If anaerobic conditions dominate the decomposition environment, microbial activity will be slow and thus decomposition will be slow. .
In arid environments, bacteria and fungi dry out and are unable to take part in decomposition.
In wet environments, anaerobic conditions will develop and decomposition can also be considerably slowed down.
The optimal activity of the decomposing microorganisms happens in the Carbon to Nitrogen ratio (C:N) range of 20:1 to 30:1 and is also dependent on temperature.
If the C:N is too high, the decomposition slows down and the microorganisms become nitrogen starved, eventually competing with the live plants for available nitrogen in the soil. If the C:N is too low, the microorganisms produce soluble nutrients in the form effective humus but very little stable humus which might help the weeds more than the crop. A good C:N ratio in turned into both effective and stable humus. While decomposing, microorganisms transform the energy stored in the organic matter (in the form of starch) to carbon-dioxide (by respiration). This process continues till most carbon has been oxidised. The remaining undecomposed carbon forms the stable humus.
Transformations and availability of oxygen and hydrogen are quite obvious (Oxygen through photosynthesis and respiration and hydrogen through water and carbohydrates/starch). Other important cycles are the carbon and nitrogen cycles.
Plants make starch or carbohydrates from carbon in the air (from carbon dioxide). These starch provide energy to the plant for growth and reproduction. Animals also derive their energy from this starch by consuming plants- their leaves, roots or fruits and/or by eating other animals who feed on plants. Micro-organisms derive their energy by feeding on dead organic matter. The animals and microorganisms digest this starch and release carbon dioxide in the air from where it is available to plants for synthesis of their food.
Thought: If man learnt how to produce starch from co2, we d be forced to consume laboratory food. All that land used to produce food right now will be sacrificed in the name of development for modern industries, malls and high rise complexes.
Other sources of carbon in nature are of course the fossil fuels which release oxides of carbon on burning. Bacteria and fungi also release some carbon while decomposing dead matter.
Plants and animals need nitrogen to synthesise proteins necessary for growth. Although nitrogen is abundant in atmosphere as nitrogen gas (N2), most plants cannot use it in that form and can only take it up in two solid forms: ammonium ion (NH4+ ) and the nitrate ion (NO3-). Most plants obtain the nitrogen they need as nitrate. Ammonium is used less by plants for uptake because in large concentrations it is extremely toxic. Animals receive the required nitrogen they need for metabolism, growth by consuming living or dead organic matter containing molecules composed partially of nitrogen.
Bacteria fix atmospheric nitrogen to usable forms in the soil for the plants and also convert nitrogen from dead matter back to nitrogen gas.
It is difficult to say what is the beginning of the cycle and what is the end. Just as absurd as it would be say that decay comes after growth or growth happens because of decay. I feel the symbolisms of circles, cycles, beginnings and end are to keep the human mind busy. Nature doesnt work in cycles, it has patterns. These patterns are what can be called the nature of a being.