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Carbon dioxide is an atmospheric constituent that plays several vital roles in the environment. It is a greenhouse gas that traps infrared radiation heat in the atmosphere. It plays a crucial role in the weathering of rocks. It is the carbon source for plants. It is stored in biomass, organic matter in sediments, and in carbonate rocks like limestone. The Carbon Cycle The primary source of carbon/CO2 is outgassing from the Earth's interior at midocean ridges, hotspot volcanoes, and subduction-related volcanic arcs. Much of the CO2 released at subduction zones is derived from the metamorphism of carbonate rocks subducting with the ocean crust. Much of the overall outgassing CO2, expecially as midocean ridges and hotpot volcanoes, was stored in the mantle when the Earth formed. Some of the outgassed carbon remains as CO2 in the atmosphere, some is dissolved in the oceans, some carbon is held as biomass in living or dead and decaying organisms, and some is bound in carbonate rocks. Carbon is removed into long term storage by burial of sedimentary strata, especially coal and black shales that store organic carbon from undecayed biomass and carbonate rocks like limestone (calcium carbonate). PhotosynthesisPlants and photosynthetic algae and bacteria use energy from sunlight to combine carbon dioxide (C02) from the atmosphere with water (H2O) to form carbohydrates. These carbohydrates store energy. Oxygen (O2) is a byproduct that is released into the atmosphere. This process is known as photosynthesis. carbon dioxide + water + sunlight -> carbohydrate + oxygen CO2 + H2O + sunlight -> CH2O + O2 Respiration Plants (and photosynthetic algae and bacteria) then use some of the stored carbohydrates as an energy source to carry out their life functions. Some of the carbohydrates remain as biomass (the bulk of the plant, etc.). Consumers such as animals, fungi, and bacteria get their energy from this excess biomass either while living or dead and decaying. Oxygen from the atmosphere is combined with carbohydrates to liberate the stored energy. Water and carbon dioxide are byproducts. oxygen + carbohydrate -> energy + water + carbohydrate O2 + CH2O -> energy + H2O + CO2 Notice that photosynthesis and respiration are essentially the opposite of one another. Photosynthesis removes CO2 from the atmosphere and replaces it with O2. Respiration takes O2 from the atmosphere and replaces it with CO2. However, these processes are not in balance. Not all organic matter is oxidized. Some is buried in sedimentary rocks. The result is that over geologic time, there has been more oxygen put into the atmosphere and carbon dioxide removed by photosynthesis than the reverse. Weathering Carbon dioxide and the other atmospheric gases dissolve in surface waters. Dissolved gases are in equilibrium with the gas in the atmosphere. Carbon dioxide reacts with water in solution to form the weak acid, carbonic acid. Carbonic acid disassociates into hydrogen ions and bicarbonate ions. The hydrogen ions and water react with most common minerals (silicates and carbonates) altering the minerals. The products of weathering are predominantly clays (a group of silicate minerals) and soluble ions such as calcium, iron, sodium, and potassium. Bicarbonate ions also remain in solution; a remnant of the carbonic acid that was used to weather the rocks. Carbonate Rocks 1. Carbon dioxide is removed from the atmosphere by dissolving in water and forming carbonic acid CO2 + H2O -> H2CO3 (carbonic acid) 2. Carbonic acid is used to weather rocks, yielding bicarbonate ions, other ions, and clays H2CO3 + H2O + silicate minerals -> HCO3- + cations (Ca++, Fe++, Na+, etc.) + clays 3. Calcium carbonate is precipitated from calcium and bicarbonate ions in seawater by marine organisms like coral Ca++ + 2HCO3- -> CaCO3 + CO2 + H2O : the carbon is now stored on the seafloor in layers of limestone Metamorphism of Carbonates Some of this carbon is returned to the atmosphere via metamorphism of limestone at depth in subduction zones or in orogenic belts CaCO3 + SiO2 -> CO2 + CaSiO3 followed by outgassing at the volcanic arc. The Greenhouse EffectMost of the sun's energy that falls on the Earth's surface is in the visible light portion of the electromagnetic spectrum. This is in large part because the Earth's atmosphere is transparent to these wavelengths (we all know that with a functioning ozone layer, the higher frequencies like ultraviolet are mostly screened out). Part of the sunlight is reflected back into space, depending on the albedo or reflectivity of the surface. Part of the sunlight is changed into infrared (lower frequency than visible light). While the dominant gases of the atmosphere (nitrogen and oxygen) are transparent to infrared, the so-called greenhouse gasses, primarily water vapor (H2O), carbon dioxide, and methane (CH4), absorb the infrared radiation. They collect this heat energy and hold it in the atmosphere. While we worry about possible global warming from the additional CO2 we put into the atmosphere by burning fossil fuels, if there was no CO2 in the atmosphere the global climate would be significantly cooler. The Climate Buffer Because of the role of CO2 in climate, feedbacks in the carbon cycle act to maintain global temperatures within certain bounds so that the climate never gets too hot or too cold to support life on Earth. The process is a large-scale example of LeChatelier's Principle. This chemical principle states that if a reaction at equilibrium is perturbed by the addition or removal of a product or reactant, the reaction will adjust so as to attempt to bring that chemical species back to its original concentration. For example, as carbonic acid is removed from solution by weathering of rocks, the reaction will adjust by producing more carbonic acid. And since the dissolved CO2 is in equilibrium with atmospheric CO2, more CO2 is removed from the atmosphere to replace that removed from solution by weathering.
What else can I help you with?
Is the nitrogen cycle fast or slow in nature?
The nitrogen cycle in nature is relatively slow.
What is the cycle involving the exchange of nitrogen between organisms and the atmosphere?
The nitrogen cycle involves the process of nitrogen fixation by certain bacteria converting atmospheric nitrogen into forms usable by plants, which are then consumed by animals. Decomposers break down organic matter into ammonia and return nitrogen to the soil. Denitrification by bacteria converts nitrates back to atmospheric nitrogen to complete the cycle.
Which organisms are most critical in the nitrogen cycle?
Bacteria are most critical in the nitrogen cycle, specifically nitrifying bacteria that convert ammonia to nitrites and then nitrates, and denitrifying bacteria that convert nitrates back to nitrogen gas. These organisms play a crucial role in recycling nitrogen in the environment.
What are some key questions to consider when studying the nitrogen cycle?
When studying the nitrogen cycle, key questions to consider include: How do nitrogen-fixing bacteria convert atmospheric nitrogen into a form that plants can use? What role do plants play in absorbing nitrogen from the soil? How do denitrifying bacteria release nitrogen back into the atmosphere? How does human activity, such as agriculture and industry, impact the nitrogen cycle?
What role does bacteria play in the nitrogen cycle?
Bacteria play a crucial role in the nitrogen cycle by converting nitrogen gas in the atmosphere into forms that plants can use, a process called nitrogen fixation. Other bacteria help break down organic matter and release nitrogen back into the soil, completing the cycle.
Is exhausted in the carbon or nitrogen cycle?
it is in the nitrogen cycle
Is the first step of the nitrogen cycle?
The first step of the nitrogen cycle is nitrogen fixation.
What are the steps in nitrogen cycle?
nitrogen fixation, denitrification, nitrification, amonification are the for steps of the nitrogen cycle.
What cycle depends on the bacteria in these nodules?
Then cycle that depends on bacteria to convert nitrogen gas into ammonia is the nitrogen cycle. This is the part of the cycle called nitrogen fixation.
Cycle which is dependent on bacteria for nitrogen fixation and denitrifcation?
the nitrogen cycle...
What is a sentence nitrogen cycle?
The nitrogen cycle is essential to the maintenance of life.
Use nitrogen cycle in a sentence?
Bacteria are essential to the nitrogen cycle.
How long does it take a betta to complete its nitrogen cycle?
A Betta does not have a "nitrogen cycle"
Can you hide from the nitrogen cycle?
No, the nitrogen cycle is a part of nature. It is nothing to be afraid of.
What cycles are penguins in?
They are in the life cycle,the carbon cycle and the nitrogen cycle. Taylor,11, from Austin, Texas They are in the life cycle,the carbon cycle and the nitrogen cycle.
What are 4 biogeochemical cycles in nature?
The Water, Oxygen, Nitrogen, and Carbon Cycle...
What is the first step of the nitrogen cycle?
The first step of the nitrogen cycle is nitrogen fixation.
