Introduction
The natural cycles are those cyclical, periodic movements and activities that determine the rhythm of nature. These cycles play a vital role in keeping the equanimity and fine balance of our Earth. These structures span from the hydrologic cycle to the carbon cycle have significant impacts on earth, environment and even human communities. Natural cycles are essential to our world, and we will look at some of these processes in this blog.
Below we will discussed about some importants natural cycle.
1. The Water Cycle
The hydrologic cycle, also known as the water cycle, constantly connects the land surface and atmosphere through evaporation and precipitation. This cycle includes processes such as evaporation from the Earth, condensation in clouds, precipitation as rain or snow, and the return of water to lakes, rivers, and oceans. It sustains life on Earth by supplying freshwater for human consumption and irrigation. Seas release water through evaporation, and plants release moisture into the atmosphere through transpiration. These processes actively support various ecological functions.
2. The Carbon Cycle
The carbon cycle forms a complex system that moves carbon through the earth’s environment, landmasses, oceans, soil, and animal life. This cycle plays a crucial role in maintaining Earth’s climate and supporting life. During photosynthesis, plants absorb carbon dioxide from the atmosphere and transfer it to animals through the food chain. When organisms die, their bodies return carbon to the soil or release it into the atmosphere. Human activities, such as burning fossil fuels, have significantly disrupted this balance and accelerated global warming.
3. The Nitrogen Cycle
The nitrogen cycle describes how nitrogen moves sequentially under, above, and within living organisms. All living organisms need nitrogen to form amino acids, DNA, and proteins. This cycle includes steps such as conversion, nitrification, and denitrification. Understanding the nitrogen cycle helps manage agricultural practices more effectively because it directly influences crop yields and soil nutrient levels.
4. The Rock Cycle
The rock cycle is an Earth process appreciating the other anthropogenic formations, their metamorphosis and recycling. With the passage of millions of years, these rocks are worn, smoothed out, transported and cemented into new rocks. Among the basic concepts of geology is the rock cycle which defines contours of the earth forms.
5. The Life Cycle
The life cycle is the meaning of birth, rise of number, production and death. It includes a number of phases, starting from birth and ending on death. This cycle as the focal point of all species between the microscopic bacteria and mammalian complexe. Life cycles are significant when considering the principles of ecological studies, conservation and the process of managing natural resources.
6. The Lunar Cycle
The lunar cycle, also called the moon’s phases refers to the periods when changes are regular and predictable in the shape of the moon as it circles around in earth. Phases, including new moon, first quarter, full moon and last quarters are included in the cycle. Human calendars, cultural practices of rituals and ceremonies have been influenced by lunar cycle, the timing of tides too has been changed by the moon.
The Oxygen Cycle
Oxygen is vital for life in the biosphere. It is a major component of all living organisms. It is drawn by man and animals during aerobic respiration from air but released by plants during photosynthesis setting up the oxygen cycle. The oxygen cycle is based on exchange of oxygen among the environmental segments –atmosphere, hydrosphere, lithosphere and biosphere.It plays an important role in atmospheric chemistry, geo-chemical transformations and life processes.
Combustion Reactions
C + `O_2` `rightarrow` `CO_2`
(Fossil fuel) (Oxygen) (Carbon dioxide)
`Ch_4` + `2O_2` `rightarrow` `CO_2` + `2H_2O`
(Methane /natural gas) (Water)
Weathering Processes of Minerals
`4F_eO` + `O_2` `rightarrow` `2Fe_2O_3`
(Ferrous oxide) (Oxygen)
(Ferric oxide)
`4Fe^{2+}` + `O_2` + `4H_2O` `rightarrow` `2Fe_2O_3`
(Ferrous ion) soluble
(Water) (Ferric oxide)
In the early stage of the earth, soluble ferrous iron consumed bulk of
oxygen giving large deposits of ferric oxide as shown in the above
reaction.
Green plants return oxygen to the atmosphere through photosynthesis:
`Co_2` + `H_2O` + hv `rightarrow` `left(CH_2oright)_x` + `o_2`
(Carbondioxide) (Water) (photon
sunlight) (Carbohydrate) (Oxygen)
The Nitrogen Cycle
Nitrogen and its compounds are essential for life processes in the biosphere. There is continuous exchange of nitrogen within the ecosystems operating the nitrogen cycle. Proteins produced by plants and animals in their metabolic processes are organic compounds of nitrogen. The major load of nitrogenous organic residue in soil originates from death and decay of plants and excreta of animals. These organic residues in soil are taken up by various soil micro-organisms for their metabolism which give products such as ammonia, nitrates and nitrites. Plants absorb nitrates from soil which re-enter the nitrogen cycle. Some soil micro-organisms break down soil nitrate into nitrogen by denitrification process while others transform nitrogen into soluble nitrogen compounds (see below Figure of Nitrogen Cycle).
The Carbon Cycle
As carbon is the backbone of biological chemistry, the carbon cycle is a very important chemical cycle. The atmosphere is the minor reservoir of carbon dioxide while the oceans are the major reservoir, containing as much as 50 times more as that of air where it is stored as bicarbonate mineral deposit on the ocean floor. The latter regulates the carbon dioxide level in the atmosphere. The cycle operates in the form of carbon dioxide exchanging among the atmosphere, biosphere and the oceans (Figure 1). The Carbon dioxide balance sheet per year is given:
Figure 1
- emissions by fossil fuel 20 billion tonnes
- emissions by deforestation and changes in land use 5.5 billion tonnes
- uptake in the oceans 5.5 billion tonnes
- uptake by carbon dioxide fertilization, i.e., photo-synthesis, 7.3 billion tonnes
Thus there is a net increase of carbon dioxide in the atmosphere of 11 billion tons per year. This can be reduced by 50 per cent if we can stop deforestation (Fig. 2).
Figure 2
The atmosphere contains 2700 billion tonnes of carbon dioxide; biosphere,vegetation and soil about 6600 billion tonnes and the oceans about 1,36,000 billion tonnes of carbon dioxide.
The Phosphate Cycle
Phosphates are necessary for the growth and maintenance of animal and human bones and teeth while organo-phosphates are required for cell division involving production of nuclear DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
Phosphate minerals exist in soluble and insoluble forms in rocks and soil. Plants absorb inorganic phosphate salts from soil and change them into organic phosphate. Animals obtain their phosphate by eating plants.After death and decay, plants and animals return phosphates to the soil.Bulk of the phosphate in soil is fixed or absorbed on soil particles but part of it is leached out into waterbodies.
The natural phosphate cycle is affected by pollution, mainly from agricultural run-off containing superphosphate and also from domestic sewage. Phosphate pollution of rivers and lakes is the cause of algal bloom (eutrophication) which reduces dissolved oxygen in water and disrupts the food chain. The phosphate cycles on land and in water are shown in Figs. 3 and 4.
Figure 4
The Sulphur Cycle
Sulphur and its compounds are required by plants and animals for synthesis of some amino acids and proteins. Some sulphur bacteria act as the media for exchanges of sulphur within the ecosystems. The sulphur cycle (Fig. 5) illustrates the circulation of sulphur and its compounds in the environment.
Figure 5
The upper half of the cycle shows how sulphur undergoes oxidation. The lower section illustrates how plants and cells convert sulphate into proteins and how bacteria break down dead plant and animal material. In polluted waters without oxygen, bacteria produce hydrogen sulphide, which forms iron sulphide deposits. In clean, oxygen-rich waters, sulphur bacteria convert sulphides into sulphates, enabling further protein production.
Conclusion
Natural cycles are the intricate and interconnected systems that make our planet a harmonious and habitable place. They influence the climate,biodiversity, geological processes, and the life and death of all living organisms. Recognizing the significance of these cycles and their influence on our world is essential for sustainable living and environmental conservation. As we strive to protect the Earth, understanding and respecting these natural cycles is crucial for maintaining the balance of our planet's delicate ecosystems.
Guru
