Biogeochemical Cycles: Detailed Overview, Environmental Science

The words "bio" and "geo," refers to the biosphere and "geo" and "chemical," refers to the elements that flow through a cycle. These three words altogether are the roots of the phrase "biogeochemical."

Atoms make up the preserved stuff that exists on Earth. Since matter cannot be generated or destroyed, it is recycled in a variety of ways throughout the Earth's system.

The remainder of the elements are present in a closed system, and the earth receives energy from the sun that is reflected back as heat. Major components include:

• Carbon

• Hydrogen

• Nitrogen

• Oxygen

• Phosphorus

• Sulphur

The biotic and abiotic parts of the ecosystem recycle these substances. The abiotic elements of the ecosystem are the lithosphere, hydrosphere and atmosphere.

Types Of Biogeochemical Cycles

Essentially, there are two categories of biogeochemical cycles:

Gaseous Cycles.: Carbon, Oxygen, Nitrogen and the water cycle

Sedimentation Cycles : Sulphur, Phosphorus, Rock cycle, etc.

Water Cycle

The passage through many phases, such as -, is referred to as the water cycle.

• Evaporation: The sun, which is the ultimate energy source, tends to cause the evaporation process. When water molecules on water bodies prefer to rise into the air, evaporation takes place. This mechanism makes it possible for the atmosphere to contain significant amounts of water.

• Condensation: As the water vapour builds up in the sky, it cools down as a result of the chilly temperatures at high altitudes. The condensation of these vapours into clouds causes them to condense into droplets and ice.

• Precipitation: If there is no dust or other contaminants, the temperature must be above 0 degrees for the vapour to condense to water, which is impossible. As a result, the water then adheres to the surface of the particle, and once the droplets are large enough, precipitation begins to fall from the clouds. Another name for this process is rainfall.

• Infiltration process: Rocks are shown to contain less water than soil due to the infiltration process, which seeps water into different soil strata. These waters may travel along rivers or streams, but they may also go quite deeply.

• Run-off: If water does not form aquifers but instead flows down the slopes of mountains and hills, it eventually forms rivers. Runoff is the name of this procedure.

The ocean 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.

Nitrogen Cycle

Because it is a component of proteins and nucleic acids, nitrogen is necessary for all living forms. Nitrogen is taken up by plants through microbial processes.

The cycle's primary stages are:

• Nitrogen fixation: In this process, atmospheric nitrogen is predominantly available in its inert state and is later transformed into usable ammonia. With the aid of precipitation, the inert form of nitrogen gas is deposited into solid during this process from the atmosphere and surface waters. After that, the nitrogen goes through a number of chemical reactions to mix with the hydrogen to create ammonia. Symbiotic bacteria carry out the entire nitrogen fixation process. Aerial fixation may result in the fixation.

• Nitrogen assimilation: Nitrogen molecules, which are present in forms like ammonia, nitrite ammonium ions, or nitrate ions, are often consumed by primary producers with the aid of their roots. They are necessary for the synthesis of proteins.

• When plants or animals die, the nitrogen that is in the organic matter tends to be released back into the soil (a process known as ammonification). The decomposers then react with the nitrogen in the soil, breaking down to produce ammonia.

• The oxidation of ammonia by bacteria of the Nitrosomonas species results in the conversion of ammonia into nitrate during the nitrification process. The process of turning nitrates into nitrates is crucial since the ammonia gas that results is extremely toxic to plants.

• Denitrification: During this process, nitrate is transformed to nitrogen, which then tends to return the nitrogen compounds to the environment. The bacteria Clostridium and Pseudomonas do this process.

Oxygen Cycle

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

The following are the cycle's key steps:

• Stage 1: Photosynthesis, which results in the release of oxygen into the atmosphere, typically occurs in all green plants.

• Stage 2: At this point, all aerobic creatures breathe in oxygen to breathe.

• Stage 3: During this stage, carbon dioxide is removed from the atmosphere by animals and then further absorbed by plants during photosynthesis.

Carbon Cycle

Carbon travels from the atmosphere to living things and back again. The carbon cycle is said to begin with plants.

The carbon cycle's primary phases are:

• Plants absorb carbon, which they use for the process of photosynthesis.

• As a result of the animals eating these plants, the carbon is absorbed into their bodies.

• Animals inevitably pass away, and when they decompose, they return carbon to the atmosphere.

• The production of fossil fuels uses some of the carbon that is not emitted.

• Due to the numerous man-made activities that utilise these fossil fuels, more carbon is released back into the atmosphere.

Phosphorus Cycle

The hydrosphere, lithosphere, and biosphere are where phosphorus mostly moves through. It is necessary for the growth of both plants and animals. But it eventually disappears from the soil. The phosphorus cycle does not go through the atmosphere like the carbon cycle does. It is claimed that the phosphorus cycle is a very sluggish process.

The following are the stages that make up the phosphorus cycle:

• Phosphate salts are mostly found in rocks, where they are broken down and drained into the soil during weathering. As a result, it can be seen that the process begins at the earth's crust.

• Plant Absorption: The plants will take up relatively little of the phosphate salts after they have been dissolved in the soil. Farmers therefore add some phosphate fertilisers for the plants to consume. However, because phosphates do not adequately dissolve in water, aquatic species cannot absorb them.

• Animals absorb the majority of the phosphorus content through the food of other animals and plants. 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 may then be used to view this process once again, and the cycle repeats.

Sulphur Cycle

Soil proteins may include sulphur, which is mostly present as an amino acid component. Eventually, after undergoing a variety of microbial changes, it is taken up by plants as sulphates.

The hydrogen sulphide (H2S) produced by the sulphur proteins undergoes further breakdown into sulphur when it interacts with oxygen. It turns into sulphate through bacterial activity so that plants may take it.

The following list of sulphur cycle stages is available:

• Decomposition of organic compounds: Proteins often produce sulphur-containing amino acids, which the bacteria Desulfotomaculum then convert to hydrogen sulphide.

• Bacteria from the Chlorobiaceae and Chromatiaceae families carry out the oxidation of hydrogen sulphide to elemental sulphur.

• Oxidation of elemental sulphur: Because plants cannot readily absorb sulphur in its elemental form, chemolithotrophic bacteria in soil convert it to sulphates.

• Sulphate Reduction: Desulfovibrio desulfuricans bacteria subsequently reduce the sulphates to hydrogen sulphide. The process is divided into two parts. In the first, sulphates are transformed to sulphites utilising ATP, and in the second, sulphate is reduced to hydrogen sulphide.

Importance Of Biogeochemical Cycles

These cycles provide an example of how energy is utilised. These cycles transport the components needed for life to exist throughout the biosphere. They are essential because they recycle materials, store them as well, and control the essential materials through physical characteristics. Ecosystems are able to continue to exist because of these cycles, which show how living and nonliving entities interact in ecosystems.Understanding these cycles is crucial if you want to know how they affect living things. Some human activities disrupt some of these natural cycles, which has an impact on nearby ecosystems. We can limit and stop these systems' harmful effects by taking a closer look at them.