Sedimentary cycles are biogeochemical cycles that have the Earth's crust as their reservoir. Iron, calcium, phosphorus, sulphur and other earthbound elements are all part of the sedimentary cycle. Sedimentary cycles differ depending on the element, but they all have a solution (or water-related) phase and a rock (or sediment) phase. This article will explain to you about Sedimentary Cycle which will be helpful in preparing the Environment syllabus for the UPSC Civil service exam.

What is a Sedimentary Cycle?

• Sedimentary cycles take a very long time to complete.
• They are regarded as less ideal cycles since they take a long time to complete their circulation.
• This is because nutritional elements may become trapped in the reservoir pool during recycling, taking a long time to emerge and continue circulation.
• The Phosphorus cycle, Calcium cycle and Sulphur cycle are the most important sedimentary cycles.

Phosphorus Cycle

• Phosphorus circulates through rocks, water, soil, sediments, and organisms in a cycle.
• Rain and weathering cause phosphate ions and other minerals to be released from rocks throughout time.
• This inorganic phosphate is subsequently dispersed throughout the soil and water.
• Inorganic phosphate is taken up by plants from the soil. Animals may eat the plants after that.
• Phosphate is integrated into organic molecules such as DNA once it reaches the plant or animal.
• When a plant or animal dies, it decomposes, releasing organic phosphate into the soil.
• Bacteria that break down organic materials to inorganic forms of phosphorus can make organic forms of phosphate available to plants in the soil. Mineralisation is the name for this process.
• Phosphorus from the soil can end up in streams and, eventually, the oceans.
• It can be absorbed into sediments over time once it reaches that location.

Phosphorus Cycle

*To know more about this topic, click this link Phosphorus Cycle

Sulphur Cycle

• The majority of the world's sulphur is bound up in rocks and salts or buried deep within oceanic sediments.
• Sulphur is also contained in the air we breathe. Both natural and human sources contribute to its presence in the atmosphere.
• Volcanic eruptions, microbiological activities, water evaporation, and decomposing organisms are just a few examples of natural resources.
• When sulphur enters the atmosphere as a result of human activity, it is primarily due to industrial activities that generate large amounts of sulphur dioxide (SO2) and hydrogen sulphide (H2S) gases.
• Sulphur dioxide reacts with oxygen to form sulphur trioxide gas (SO3), or with other chemicals in the atmosphere to produce sulphur salts, when it reaches the atmosphere.
• Sulphur dioxide can also form sulphuric acid when it reacts with water (H2SO4).
• Dimethyl Sulphide, which is exhaled into the atmosphere by plankton species, can also be used to make sulphuric acid.
• All of these particles will either fall back to earth or will react with rain and fall as acid deposits.
• Plants will then absorb the particles, which will then be released back into the atmosphere, restarting the sulphur cycle.

Sulphur Cycle

*To know more about this topic, click this link Sulphur Cycle

Calcium Cycle

• Calcium is primarily found in the form of rock, minerals, or structural calcium embedded in the mineral crystal lattices of soil particles, and it is not easily available.
• The majority of calcium in the soil is insoluble unless it is 'weathered off' of minerals or bacteria break down organic materials into soluble calcium.
• Some calcium, however, is held loosely or securely on the soil or in the soil solution and is available to plants and microbes.
• Animals, microbes, and plants decompose, and the calcium in their bodies is mineralized and released back into the soil.
• Roots also return minerals, carbohydrates, and other chemicals to the soil on a regular basis, including calcium.
• Calcium is adsorbed to the surface of the clay and negatively charged organic particles in the soil because it is a positively charged ion. Positively charged ions (cations) bind to soil particles and are referred to as "exchangeable ions" because they can be exchanged with other ions in the soil solution.
• Calcium enters an organic phase when it is taken by plants or microbes. Calcium is constantly exchanged between plant roots, microbes, and soil in this form.
• Decomposers break down a plant, animal, or soil fauna after it dies, and calcium is released back into the soil in a soluble form.
• As a result, calcium alternates between the soluble (and available) and the insoluble (and unavailable) phases.

Calcium Cycle

Conclusion

The sedimentary cycles are one of the most important biogeochemical cycles. They are very crucial to ecosystems. They function as a recycling system in nature. Decades of rigorous research also revealed that the sedimentary cycle is not only found on Earth but also on Mars.

GS Mains Questions and Model Answers 

Q1: Describe the significance of the sedimentary cycle in geological processes.

Answer: The sedimentary cycle is significant in geological processes as it regulates the Earth's surface environment. Through weathering, rocks are broken down, allowing for nutrient recycling essential for ecosystems. The transportation of sediments influences landscape formation and erosion patterns, contributing to soil fertility and habitat diversity. The cycle plays a critical role in the carbon cycle as well, with carbonates being a major component of sedimentary rocks like limestone. Understanding this cycle aids in resource management, including mineral exploration and sustainable land use.

Q2: Discuss how human activities impact the sedimentary cycle and its associated ecosystems.

Answer: Human activities such as deforestation, mining, and urbanization significantly impact the sedimentary cycle. Deforestation increases soil erosion, disrupting sediment transport and deposition patterns. Mining activities remove surface layers, altering natural sedimentary processes and leading to habitat destruction. Urbanization changes drainage patterns, affecting sediment transport and increasing sedimentation in water bodies, which can harm aquatic ecosystems. These impacts can lead to decreased biodiversity, altered nutrient cycles, and increased pollution, underscoring the need for sustainable practices to protect sedimentary processes.

Q3: Explain the relationship between the sedimentary cycle and climate change.

Answer: The sedimentary cycle is intricately linked to climate change, as climatic conditions influence weathering rates, sediment transport, and deposition. Changes in temperature and precipitation patterns can alter erosion processes, impacting sediment supply to rivers and oceans. Additionally, the sedimentary cycle plays a role in carbon sequestration; for instance, the formation of carbonate rocks helps regulate atmospheric carbon dioxide levels. As climate change affects ocean acidity and temperature, it can disrupt the formation of calcium carbonate structures in marine environments, impacting biodiversity and altering sedimentary processes.

Previous Year Questions on  Sedimentary Cycle

1. UPSC CSE Prelims 2021

Question: Which of the following statements is true regarding sedimentary rocks?

a) They are formed from cooling and solidification of magma.

b) They are formed from the compression and cementation of sediments.

c) They are formed from metamorphosed igneous rocks.

d) They are primarily composed of minerals that crystallize from solutions.

Answer: b) They are formed from the compression and cementation of sediments.

Explanation: Sedimentary rocks are primarily formed through the processes of compaction and cementation of sediments that accumulate over time. They differ from igneous rocks, which form from the cooling of magma, and from metamorphic rocks, which arise from the alteration of existing rocks due to heat and pressure.

2. UPSC CSE Mains 2019

Question: Discuss the importance of sedimentary cycles in understanding Earth’s history.

Answer: Sedimentary cycles are crucial for understanding Earth's history as they provide insights into past environmental conditions, climate changes, and biological evolution. The layers of sedimentary rocks record the history of sediment deposition over time, preserving fossils that reveal information about past life forms and ecosystems. By studying these sedimentary records, geologists can reconstruct ancient environments, track changes in biodiversity, and understand the impacts of historical climate fluctuations. Additionally, sedimentary cycles play a role in the formation of natural resources like coal, oil, and gas, making them essential for both scientific research and economic development. Understanding these cycles helps predict future geological processes and their implications for the planet.