Nutrient Cycle:

There are three main parts to this cycle, those being dead organic matter, biomass, and soil. The biomass is due to the uptake by plants from the soil, and the soil comes from the dead organic matter once it decomposes. Likewise, the dead organic matter comes from the biomass once it dies. However, there are external factors that can lead to this too. For instance, dead organic matter can come from material dissolved in rain. In addition, dead organic matter can leave as runoff, while soil also experiences loss through leaching. However, weathered rock contributes to the said soil. It should also be noted that the size of the three main parts of the cycle varies depending on the biome that is present. 

Water Cycle: 

This should be familiar to many. Precipitation leads to runoff but can also lead to infiltration/percolation. Once under the layer of soil or rock, there is throughflow or groundwater flow, the latter which leads to ocean. This area of storage will eventually evaporate and have a phase shift to a gas. Later on, however, it will condense and turn back into precipitation. 

Carbon Cycle: 

Atmospheric carbon dioxide, naturally, would only come from plants and animals that respire, and would likewise provide the former with photosynthesis needed. Once animals die however, they will be part of the fossils and the source for fossil fuels. When factories use this for emissions, it creates a synthetic part to to this cycle by adding in extra atmospheric carbon dioxide. This is what makes an initially carbon neutral cycle to one with more atmospheric carbon dioxide than can be handled. 

Nitrogen Cycle: 

Though plants and animals need to consume nitrogenous nutrients, it cannot come directly from the atmospheric nitrogen that is present. Rather, it needs to obtain nitrates in the system. Therefore, by means of nitrogen fixation through special types of bacteria, it can convert this to ammonia, which later on, by the process of nitrification by other types of bacteria, will turn into nitrites, and finally nitrates. Natural occurrences such as lightning and volcanic activity can also lend its way directly into nitrites then nitrates. Animals and plants can assimilate these nitrates for nutrients, but when they die, they also turn into ammonia in the soil. Likewise, a different set of bacteria can also turn the nitrates directly into the atmospheric nitrogen through denitrification. It is especially important to know about this due to the plenty of inorganic fertilizers and pesticides used in agriculture. Excess nitrogen will cause dense growth of plant life and death of animal life from lack of oxygen.