Biogeochemical Cycles And Decision Making
Waste management decisions are often made among competing interests and perspectives. These involve trade-offs. For example, remediating a contaminated site, may call for excavation of soil, which is then incinerated. The complete incineration will result in generating and emitting greenhouse gases. Determining whether this approach is successful and appropriate depends on the extent and quality of options from which these emissions occur. For example, if dioxin-laden soil is incinerated, this may have been the only viable approach to detoxify a very toxic and persistent compound. Releasing CO2 in this case is truly a measure of success.
One of the biggest engineering challenges is how to select and operate control technologies in a manner fully cognizant and deferential of the biogeochemical cycles. This view can support work to reduce the impact of global climate change debate, in light of the seeming paucity of ways to deal with the problem. The National Academy of Engineering has identified the most important challenges to the future of engineering. Both the nitrogen and carbon biogeochemical cycles are explicitly identified among the most pressing engineering needs.
Types And Importance Of Biochemical Cycle
All the elemental matters tend to go through a cycle in the biosphere which is said to be an interconnected process that is said to be the biogeochemical cycle. There are basically four types of cycles that are present which handle the overall consumption and decaying of nutrients in the environment. There are also materials that are recycled via erosion, weathering, water drainage, and the movement of tectonic plates. These materials are further used by other organisms for their basic functioning.
Definition Of Biogeochemical Cycle
A biogeochemical cycle is among the natural cycles that move stored matter through an ecosystems biotic and abiotic components. The stored matter can be oxygen, nitrogen, sulfur, phosphorus, and carbon.
These elements are very essential to the living cells of both plants and animals to function properly. Their significance or importance means that they need to cycle through the different spheres of the Earth in order to maintain a balance of the element in all these spheres. A balance is indeed necessary to avoid a backlash of the element on the earth, in the form of a deficiency of any of the elements in any of the spheres hence, the need for the cycle of these elements.
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Carbon Cycling And Climate
The discussion in the previous section indicates that there are many drivers and constraints involved in climate . The increased amounts of CO2 will likely affect global temperature, which affects biomes and the kinetics within individual ecosystems. Ecological structure, such as tree associations, canopies, and forest floors, as well as wetland structures may change, so that conditions may become reduced, with an attendant increase in anaerobic microbial decomposition, meaning greater releases of CH4, which would mean increasing global temperatures, all other factors being held constant. However, if greater biological activity and increased photosynthesis is triggered by the increase in CO2, and wetland depth is decreased, CH4 global concentrations would fall, leading to less global temperature rise. Conversely, if this increased biological activity and photosynthesis leads to a decrease in forest floor detritus mass, then less anaerobic activity may lead to lower releases of CH4. In actuality, there will be increases and decreases at various scales, so the net effects on a complex, planetary system is highly uncertain.
FIGURE 21.3. Systematic view of changes in tropospheric carbon dioxide.
Thick arrows indicate whether this factor will increase , decrease , or vary depending on the specifics . Question mark indicates that the type and/or direction of change are unknown or mixed. Thin arrows connect the factors as drivers toward downstream effects.
Types Of Biogeochemical Cycles
The types of nutrient cycles largely fall under
Sedimentary cycles- Reservoir in the sedimentary biogeo cycle is Earths crust and includes earth-bound elements such as phosphorus, calcium, iron, and sulfur among others.
Gaseous cycles- Reservoirs in the gaseous biogeo cycle are air or ocean and include carbon, oxygen, and nitrogen.
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Rapid Carbon Biogeochemical Cycles
In this cycle, inorganic carbon, which is present in the atmosphere as CO2, is captured by autotrophs. These are usually photosynthesizing organisms such as plants, bacteria and algae.
During photosynthesis, the carbon is converted into organic compounds such as glucose, which are stored within the bodies of these organisms. This carbon can be stored for many hundreds of years within the bodies of plants in areas such as tropical rainforests.
When the organic compounds are consumed by heterotrophs, they are passed through the food web, where they are broken down into useful substances using cellular respiration. Cellular respiration produces CO2, which is released back into the atmosphere.
The ocean is the second largest carbon sink. As well as dissolved inorganic carbon which is stored at depth, the surface layer holds large amounts of dissolved carbon that is rapidly exchanged with the atmosphere.
Key Points On Carbon Cycle
- Carbon cycle explains the movement of carbon between the earths biosphere, geosphere, hydrosphere and atmosphere.
- Carbon is an important element of life.
- Carbon dioxide in the atmosphere is taken up by green plants and other photosynthetic organisms and is converted into organic molecules that travel through the food chain. Carbon atoms are then released as carbon dioxide when organisms respire.
- The formation of fossil fuels and sedimentary rocks contributes to the carbon cycle for very long periods.
- The carbon cycle is associated with the availability of other compounds as well.
Explore more information about the carbon cycle, its definition, process, carbon cycle diagram, or any other related topics by registering at BYJUS.
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Human Impacts On The Carbon Biogeochemical Cycle
Humans are having a drastic impact on the natural cycling of carbon in the atmosphere and in the oceans.
Fossil fuels, which have stored vast amounts of carbon for millions of years, are being burned at a rate that is too fast for it to be returned to carbon sinks. Instead it is being released into the atmosphere as carbon dioxide and methane which prevents heat from escaping the atmosphere, resulting in the greenhouse effect.
Additionally, among other disruptive practices, deforestation is releasing carbon stored within plant matter and is reducing the number of plants available to capture it this is especially true in tropical rainforests and peat bogs.
The unnatural interference with this delicate biogeochemical cycle by humans could have severe consequences for our planet.
The Biological Carbon Cycle
Organisms are connected in many ways, even among different ecosystems. A good example of this connection is the exchange of carbon between heterotrophs and autotrophs by way of atmospheric carbon dioxide. Carbon dioxide is the basic building block that autotrophs use to build high-energy compounds such as glucose. The energy harnessed from the Sun is used by these organisms to form the covalent bonds that link carbon atoms together. These chemical bonds store this energy for later use in the process of respiration. Most terrestrial autotrophs obtain their carbon dioxide directly from the atmosphere, while marine autotrophs acquire it in the dissolved form .
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Importance Of The Carbon Cycle
The carbon cycle is crucially important to the biosphere. If not for the recycling processes, carbon might long ago have become completely sequestered in crustal rocks and sediments, and life would no longer exist ). Photosynthesis not only makes energy and carbon available to higher trophic levels, but it also releases gaseous oxygen . Gaseous oxygen is necessary for cellular respiration to occur. Photosynthetic bacteria were likely the first organisms to perform photosynthesis, dating back 2-3 billion years ago. Thanks to their activity, and a diversity of present-day photosynthesizing organisms, Earths atmosphere is currently about 21% O2. Also, this O2 is vital for the creation of the ozone layer, which protects life from harmful ultraviolet radiation emitted by the sun. Ozone is created from the breakdown and reassembly of O2.
The global carbon cycle contributes substantially to the provisioning ecosystem services upon which humans depend. We harvest approximately 25% of the total plant biomass that is produced each year on the land surface to supply food, fuel wood and fiber from croplands, pastures and forests. In addition, the global carbon cycle plays a key role in regulating ecosystem services because it significantly influences climate via its effects on atmospheric CO2 concentrations.
What Is The Biogeochemical Cycle In Biology
Hereof, what are the biogeochemical cycles and why are they important?
carbon cyclenitrogen cycleoxygen cyclephosphorus cyclewater cycle
What is an example of a biogeochemical cycle?
What is the role of the biogeochemical cycles?
RoleBiogeochemical Cyclingbiogeochemical cyclesbiogeochemical cycle
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The Biogeochemical Carbon Cycle
The movement of carbon through land, water, and air is complex, and, in many cases, it occurs much more slowly than the movement between organisms. Carbon is stored for long periods in what are known as carbon reservoirs, which include the atmosphere, bodies of liquid water , ocean sediment, soil, rocks , and Earths interior.
As stated, the atmosphere is a major reservoir of carbon in the form of carbon dioxide that is essential to the process of photosynthesis. The level of carbon dioxide in the atmosphere is greatly influenced by the reservoir of carbon in the oceans. The exchange of carbon between the atmosphere and water reservoirs influences how much carbon is found in each. Carbon dioxide from the atmosphere dissolves in water and reacts with water molecules to form ionic compounds. Some of these ions combine with calcium ions in the seawater to form calcium carbonate , a major component of the shells of marine organisms. These organisms eventually die and their shells form sediments on the ocean floor. Over geologic time, the calcium carbonate forms limestone, which comprises the largest carbon reservoir on Earth.
Everyday Connection Chesapeake Bay
The Chesapeake Bay has long been valued as one of the most scenic areas on Earth. It is now in distress and is recognized as a declining ecosystem. In the 1970s, the Chesapeake Bay was one of the first ecosystems to have identified dead zones, which continue to kill many fish and bottom-dwelling species, such as clams, oysters, and worms. Several species have declined in the Chesapeake Bay due to surface water runoff containing excess nutrients from artificial fertilizer used on land. The source of the fertilizers is not limited to agricultural practices. There are many nearby urban areas and more than 150 rivers and streams empty into the bay that are carrying fertilizer runoff from lawns and gardens. Thus, the decline of the Chesapeake Bay is a complex issue and requires the cooperation of industry, agriculture, and everyday homeowners.
Of particular interest to conservationists is the oyster population it is estimated that more than 200,000 acres of oyster reefs existed in the bay in the 1700s, but that number has now declined to only 36,000 acres. Oyster harvesting was once a major industry for Chesapeake Bay, but it declined 88 percent between 1982 and 2007. This decline was due not only to fertilizer runoff and dead zones but also to overharvesting. Oysters require a certain minimum population density because they must be in close proximity to reproduce. Human activity has altered the oyster population and locations, greatly disrupting the ecosystem.
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Eutrophication And Dead Zones
Eutrophication occurs when excess phosphorus and nitrogen from fertilizer runoff or sewage causes excessive growth of algae. Algal blooms that block light and therefore kill aquatic plants in rivers, lakes, and seas. The subsequent death and decay of these organisms depletes dissolved oxygen, which leads to the death of aquatic organisms such as shellfish and fish. This process is responsible for dead zones, large areas in lakes and oceans near the mouths of rivers that are periodically depleted of their normal flora and fauna, and for massive fish kills, which often occur during the summer months ). There are more than 500 dead zones worldwide. One of the worst dead zones is off the coast of the United States in the Gulf of Mexico. Fertilizer runoff from the Mississippi River basin created a dead zone, which reached its peak size of 8,776 square miles in 2017. Phosphate and nitrate runoff from fertilizers also negatively affect several lake and bay ecosystems including the Chesapeake Bay in the eastern United States.
What Do Biogeochemical Cycles Connect
The biogeochemical cycles on Earth connect the energy and molecules on the planet into continuous loops that support life. The basic building blocks of life like water, oxygen, carbon, sulfur, nitrogen and phosphorous are recycled and go back into their respective cycles repeatedly. The biogeochemical cycles also create reservoirs of these building blocks such as the water stored in lakes and oceans and sulfur stored in rocks and minerals.
The biogeochemical cycles have existed on Earth for billions of years and the elements that make up a modern-day human have been part of many other organisms and non-living molecules in the past. The process known as nucleosynthesis that occurred during and after the Big Bang was the ultimate source of all the materials that make up the universe. For example, the lighter elements hydrogen and helium formed within the first few minutes of the Big Bang and went on to help form the first stars. When the stars got old and eventually exploded, these elements went on to be incorporated into other cycles, processes, stars and planets in the universe. In addition to recycling elements and molecules, the explosion of stars also creates new materials like metals that are expelled into space and become part of the whole process.
The image above shows the carbon cycle, one of the biogeochemical cycles on Earth that recycles and stores the elements essential for life.
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Human Alteration Of The Carbon Cycle
Atmospheric CO2 concentration increased from 280 parts per million to 413 ppm between the start of industrial revolution in the late eighteenth century and 2020. This reflected a new flux in the global carbon cycleanthropogenic CO2 emissionswhere humans release CO2 into the atmosphere by burning fossil fuels and changing land use. Fossil fuel burning takes carbon from coal, gas, and oil reserves, where it would be otherwise stored on very long time scales, and introduces it into the active carbon cycle. Land use change releases carbon from soil and plant biomass pools into the atmosphere, particularly through the process of deforestation for wood extraction or conversion of land to agriculture. In 2018, the additional flux of carbon into the atmosphere from anthropogenic sources was estimated to be 36.6 gigatons of carbon a significant disturbance to the natural carbon cycle that had been in balance for several thousand years previously. High levels of carbon dioxide in the atmosphere cause warming that results in climate change. /03%3A_Conservation/3.02%3A_Threats_to_Biodiversity/3.2.07%3A_Climate_Change” rel=”nofollow”> Threats to Biodiversity and Climate Change for more details.)
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date: 16 September 2022
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What Are Biogeochemical Cycles
The most common elements in organic molecules, carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus, are only available in the ecosystem in limited amounts. Therefore, these nutrients must be recycled through both biotic and abiotic components of the ecosystem, in processes generally called biogeochemical cycles.
Biogeochemical Cycles and Decomposition
The matter that makes up living organisms, like water, carbon, nitrogen, sulfur and phosphorous, exist in limited quantities within the ecosystem and must be conserved and recycled. This matter can take a variety of chemical forms and spend extended periods of time in the atmosphere, on or underneath the land, and in aquatic environments. A key component in the breakdown and recycling of nutrients in the ecosystem is decomposition, which is influenced by temperature, moisture, and nutrient availability. For example, organic material is decomposed much faster in rainforests compared to temperate environments, which have lower temperatures and more seasonal climates.
Michalak, Anna M., Eric J. Anderson, Dmitry Beletsky, Steven Boland, Nathan S. Bosch, Thomas B. Bridgeman, Justin D. Chaffin, et al. Record-Setting Algal Bloom in Lake Erie Caused by Agricultural and Meteorological Trends Consistent with Expected Future Conditions.Proceedings of the National Academy of Sciences 110, no. 16 : 644852.
Water Cycle Or Hydrological Cycle
The hydrological cycle, also known as the biogeochemical cycle of water, describes how water is distributed or circulated, and recycled all across Earths systems.
Water is essential for all living organisms to survive and grow, making it one of the most essential substances on the planet. It is utilized by complex organisms to dissolve vitamins and minerals and to transport these substances , along with hormones, antibodies, oxygen, and other substances, throughout the body and out of the body in the form of sweat. It also supports the enzymatic and chemical reactions needed for metabolic activities and to regulate body temperature.
Weather patterns are caused by the biogeochemical cycle of water on a geographical scale, especially in the temperature, amount, and movement of the water which all have an impact on all weather systems. Water interacts with its surroundings in various forms , and in doing so, it changes the temperature and pressure of the atmosphere, causing wind, rain, and currents, and changing the structure of earth and rock through weathering.
The water cycle steps
The suns energy, which heats up the oceans and other surface waters, is the driving force of the water cycle. This is because the heat causes evaporation and sublimation of frozen water, both of which deposit large amounts of water vapor into the atmosphere.
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Top 5 Types Of Biogeochemical Cycle
The following points highlight the top five types of biochemical cycle existing in ecosystem. The types are: 1. Hydrologic Cycle 2. Gascons Nutrient Cycle 3. Sedimentary Nutrient Cycle 4. Phosphorus Cycle 5. Sulphur Cycle.
Type # 1. Hydrologic Cycle:
In the hydrologic cycle there occurs an interchange of compounds between the earths surface and the atmosphere via precipitation and evaporation. The biota of the ecosystem plays an accessory role in the cycle and the presence or absence of the biota does not affect the movement of the cycle.
However, it is an established fact that a significant amount of water is incorporated by the-biota of the ecosystem in protoplasmic synthesis and also there is a substantial return to the atmosphere by way of transpiration.
According to him the world precipitation per year amounts to 4.46 geograms . Of this amount 0.99 geogram falls on land and 3.47 geogram falls on ocean surface. The water content of the earths surface is 266,069-88 geogram. The water content of the various parts of the earth is given below.
Characteristics of hydrological cycle:
a. The general world precipitation pattern is dependent upon the interaction of several forces. Primary of these forces is the interaction between atmospheric circulation and the topography. The distribution of the major ecosystems is dependent upon the interactions.
Type # 2. Gascons Nutrient Cycle:
A. Carbon cycle: