Biogeochemical Cycles

May 23, 2023, 16:45 IST

If you are looking for biogeochemical cycles, you have come to the right place!

The biogeochemical cycle will be covered in this article. All elemental materials go through a biosphere revolution, a linked process known as the biogeochemical cycle. Four types of cycles handle the general consumption and decomposition of environmental nutrients.

This article will discuss the many types of biogeochemical cycles and how humans can affect them.

Introduction

A cyclical or recurring pathway through which a chemical element or molecule travels through biotic (biosphere) and abiotic (lithosphere, atmosphere, and hydrosphere) elements of an ecosystem are known as a biogeochemical cycle.

What are Biogeochemical Cycles?

A biogeochemical cycle is a natural process through which the constituent parts of living things are moved about. In the biogeochemical cycles, natural elements go from abiotic (non-living) to biotic (life) components.

The word "biogeochemical" designates three elements in each cycle. They are chemical, geological, and biological aspects.

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Types of Biogeochemical Cycles

The two main types of Biogeochemical cycles are Gaseous cycles and Sedimentary Cycles based on their reservoir.

The six main types of biogeochemical cycles coming under the Gaseous and Sedimentary cycles are the water, oxygen, carbon, nitrogen, sulfur, and phosphorus cycles.

Water Cycle

Water is a crucial part of the cycle, as water is required for life to exist. Evaporation from the sea surface is essential for precipitation caused by atmospheric water vapour. Weather, pressure, and temperature all significantly depend on the water cycle in the environment.

The water cycle describes the progression through many stages, including

• Evaporation: The ultimate energy source, the sun, tends to cause the evaporation process. When water molecules on water bodies tend to rise into the air, evaporation takes place. This technique enables a lot of water vapours in the atmosphere.
• Condensation: As the water vapour builds up in the sky, it cools down due to the chilly temperatures at high altitudes. The condensation of these vapours in clouds causes them to condense into droplets and ice.
• Precipitation: When the temperature rises above 0 degrees, water vapour condenses, which is impossible if there is no dust or other impurity in the air. As a result, the water clings to the particle's surface, and when the droplets are big enough, they fall as a precipitate from the clouds. Another name for this process is rainfall.
• Infiltration: During this process, water seeps into different soil layers, and it is discovered that rocks contain less water than soil. While this water may travel along rivers or streams, it may also travel
• Run-off: If water does not form aquifers but flows down the sides of mountains and hills, it eventually includes rivers because it follows gravity. Run-off is the name of this procedure.

Carbon Cycle

The carbon cycle involves the transfer of carbon from the atmosphere to living things and back again. The carbon cycle is said to begin with plants.

The primary phases of the Carbon Cycle are:

• Plants absorb carbon, which they use for photosynthesis.
• Various animals then eat these plants, absorbing the carbon into their bodies.
• Animals inevitably pass away, returning carbon to the atmosphere when decomposing. Another way is through animal respiration, carbon is sent back to the atmosphere.
• The production of fossil fuels uses some of the carbon that is not emitted.
• The numerous artificial activities that utilise these fossil fuels release more carbon into the atmosphere.

Oxygen Cycle

The oxygen transfer through the atmosphere, biosphere, and lithosphere is known as the oxygen cycle. Through the process of photolysis, it is discharged.

The following are the cycle's main steps:

• Stage 1: Photosynthesis, which results in the release of oxygen into the atmosphere, typically occurs in all green plants.
• Stage 2: All aerobic creatures then inhale oxygen for respiration.
• Stage 3: During this stage, carbon dioxide is removed from the atmosphere by animals and then further absorbed by plants during photosynthesis.

Nitrogen Cycle

Nitrogen is required for life because it is found in nucleic acids and proteins. Plants take up nitrogen through microbial processes.

The cycle's primary stages are:

• Nitrogen fixation: In this process, atmospheric nitrogen is primarily present in the inactive state, which is later changed into usable ammonia. Precipitation assists in this process by converting the inert form of nitrogen gas from the atmosphere and surface waters into solids. After going through various procedures, hydrogen and nitrogen combine to make ammonia. Symbiotic bacteria carry out the entire nitrogen fixation process. Fixation can occur due to atmospheric focus.
• Nitrogen assimilation: Nitrogen compounds, which can be found in ammonia, nitrite ammonium ions, or nitrate ions, are often consumed by the primary producers with the aid of their roots. They are necessary for the synthesis of proteins.
• Ammonification: The nitrogen contained in the organic matter tends to be released back into the soil when plants or animals pass away. The decomposers then react with the nitrogen in the ground, breaking it down to produce ammonia.
• Nitrification: The oxidation of ammonia by bacteria of the Nitrosomonas species will frame the conversion of ammonia into nitrate in this process. Turning nitrates into nitrates is crucial since the resulting ammonia gas is highly toxic to plants.
• Denitrification: During this process, nitrate is transformed into nitrogen, which then tends to return the nitrogen compounds to the atmosphere. The bacteria Clostridium and Pseudomonas perform this process.

Sulfur Cycle

Sulfur, mostly found as an amino acid component may be found in soil as a protein. After undergoing various microbiological changes, plants eventually take it up as sulphates. The sulfur proteins change into hydrogen sulfide (H2S), which is then broken down into sulfur in interaction with oxygen. It turns into sulfate by bacterial activity, which plants can then take.

The following steps make up the sulfur cycle:

• Decomposition of organic compounds: Proteins tend to release amino acids containing sulfur acids, which are then converted to hydrogen sulfide by the Desulfotomaculum bacteria.
• Oxidation of elemental sulfur: Because plants cannot readily absorb sulphur in its basic form, chemolithotrophic bacteria in the soil convert it to sulfates.
• Sulfate Reduction: Desulfovibrio desulfuricans bacteria reduce the sulfates to hydrogen sulfide. The process has two steps: first, the sulfates are transformed to sulphites utilising ATP, and then the sulfate is reduced to hydrogen sulfide.
• Oxidation of hydrogen sulfide to elemental sulfur: Bacteria from the Chromatiaceae and Chlorobiaceae families carry out this activity.

Phosphorus Cycle

Phosphorus is mostly found in the hydrosphere, lithosphere, and biosphere. It is necessary for the growth of both plants and animals. However, it slowly disappears from the Earth. The phosphorus cycle does not go through the atmosphere like the carbon cycle. It is believed that the phosphorus cycle is a prolonged process.

The following steps make up the phosphorus cycle:

• Weathering: Because phosphate salts are mostly found in rocks, they are broken down and washed from the rocks into the earth. This indicates that the process begins at the earth's crust.
• Plant Absorption: Plants will eventually take up some phosphate salts that have been dissolved in the soil, although the amount is minimal. Therefore, farmers add some phosphate fertilisers to the ground for the plants to consume. However, because phosphates do not adequately dissolve in water, aquatic life cannot absorb them.
• Animal Absorption: Animals consume other animals and plants, which helps them absorb most phosphorus content. Most creatures have phosphorus cycles that are more rapid than those found in rocks.
• Return of phosphorus to the ecosystem: When plants and animals die, their bodies release phosphorus into the environment, which is subsequently transformed into an inorganic form and recycled into rocks and soil. Weathering can then be used to see this process again, and the cycle repeats.

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Importance of Biogeochemical Cycles

These cycles exemplify how energy is utilised. These cycles transport the components needed for life to exist throughout the biosphere. They are essential because they recycle, store, and control crucial materials through physical facets. Ecosystems can continue because these cycles show how living and non-living things interact in ecosystems.

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Human Impacts on Biogeochemical Cycles

• People have been causing these biogeochemical cycles to change. The way that carbon and nitrogen flow through the Earth alters when we clear forests build more factories and drive more vehicles that consume fossil fuels.
• These changes bring about climate change because they increase the number of greenhouse gases in the air.
• Due to human activity, atmospheric carbon dioxide has grown by around 40% compared to pre-industrial levels. In contrast, the amount of nitrogen available to ecosystems has increased by more than twice as much.
• Phosphorus and other elements have shown comparable patterns, and these changes significantly affect biogeochemical cycles and climate change.

Biogeochemical Cycles: FAQs

Q1. Which biogeochemical cycle is crucial to life on Earth?

Ans. The carbon cycle, one of the most critical processes on Earth, is how biosphere organisms recycle and reuse carbon.

Q2. What could impact biogeochemical cycles?

Ans. The primary contributors to these increases include the burning of fossil fuels, changing land cover, the production of cement, and the extraction and production of fertiliser to sustain agriculture.

Q3. What relationships exist between the biogeochemical cycles?

Ans. The energy and chemicals on Earth are linked together into ongoing cycles by the biogeochemical cycles necessary for maintaining life.

Q4. How are the biogeochemical cycles affected by temperature?

Ans. An increase in temperature typically speeds up the buildup of nutrients available in the soil and facilitates the decomposition of soil organic matter.

Q5. How do biogeochemical cycles work?

Ans. The exchanges of matter and energy that drive the biogeochemical cycles can be observed experimentally through reservoir imbalance over long periods.