Turnover Rate
In the substance cycle, the larger the turnaround rate, the shorter the turnaround time. For example, the turn-turn time of carbon dioxide in the large air ring is about one year (photosynthesis from the large carbon dioxide); a turn-up time of molecular nitrogen in the atmosphere is 1 million years (mainly the nitrogen moisture to the nitrogen to transform the nitrogen molecule to Ammonia nitrogen is used by creatures); the turn-around time of water in the atmosphere is 10.5d, that is, the moisture in the atmosphere is approximately 34 times a year. In the ocean, silicon has the shortest turnover time, about 800s, the longest sodium, about 206 million.
rate
The rate of substance cycles varies greatly in space and time, and the most important factors affecting the cycle rate of the substance: 1 Circulating element: the cycle rate The chemical characteristics of the circulating element are caused different from the way organisms that are organic organisms; 2 growth rates of biology: This factor affects the rate of absorption speed of the organism and the speed of motion in the food chain; 3 organic decomposition rate: suitable The environment is conducive to the survival of the resolve, and the organism quickly decomposes, quickly releases the substances in the organism, re-enter the circulation.
State
The material cycle of the ecosystem can be divided into three types, namely water cycle, gas cycle, and sedimentary cycle.
All material circulation in the ecosystem is completed under the promotion of water cycles, so there is no cycle of water, there is no ecosystem function, and life will also be difficult to maintain. In the gas cycle, the main storage library of the substance is atmospheric and the ocean, and the circulation is closely related to the atmosphere and the ocean. It has obvious global, and the circulatory performance is best perfect. Any material belonging to a gas type, molecular or certain compounds often participate in the circulation process in the form of a gas. The substances belonging to this class aerobic, carbon dioxide, nitrogen, chlorine, bromine, fluorine, etc. The gas cycle is fast, the material is abundant, and it will not be exhausted. The main reservoir is associated with rock, soil and water, such as phosphorus, sulfur cycles, and the like. The deposition cycle speed is relatively slow, and the substances involved in the deposition cycle are mainly through the weathering of the rock and the dissolution transition of the deposit into the nutrients that can be used by the bio-utilization, and the subsea deposit is converted to the rock ring component. A quite long, slow, unidirectional material transfer process, time to be a millennium. The main reservoirs of these deposition cycles are in soil, sediments and rocks, without gas, and therefore the global circulation of such substances is not as good as the gas type circulation, and the cycle performance is also very imperfect. Subscribed by deposition cycles include phosphorus, calcium, potassium, sodium, magnesium, manganese, iron, copper, silicon, etc., of which phosphorus is more typical deposition cycle substance, which is released from the rock, and finally deposited in the sea. Convert to new rocks.
Gas cycle and deposition cycle Although it is characterized, it can be driven by energy and can depend on water cycle.
The substance circulation in the ecosystem is generally in a stable balance in natural state. That is, for a certain substance, the input and output of each major library are substantially equal. Most gas-type circulating materials such as carbon, oxygen and nitrogen circulation, due to a large atmospheric accumulator, their short-lived self-regulation is possible. For example, due to the combustion of the fossil fuel, the local carbon dioxide concentration increases, the increase in the amount of carbon dioxide absorption is used to increase the amount of carbon dioxide absorption by air, and the concentration is rapidly reduced to the original level, and the balance is reached. The sediment cycle of sulfur, phosphorus, etc. is susceptible to human activity because of the sulfur, phosphoric library in the crustal, and therefore it is not easy to be adjusted compared to the atmosphere. Therefore, if these materials flow into the reservoir in the cycle, they will become a substance that cannot be utilized for a long time.
The carbon circulation between the organism and the atmosphere obtains carbon dioxide from the air, converted into glucose through photosynthesis, and then integrated into a carbon compound of the plant, and passes the carbon compound of the animal. . Plant and animal respiratory action transforms a portion of carbon in the intake into carbon dioxide to release the atmosphere, and the other part constitutes the organism of the organism or stored in the body. After the death, the plant is dead, the carbon in the residue is also a carbon dioxide by the decomposition of the microorganism and ultimately discharged into the atmosphere. The carbon dioxide in the atmosphere is about 20 years. Part of the (about one third), the plant residue is buried by deposits before being decomposed. It is an organic deposit. These sediments have been transformed into mineral fuels in thermal energy and pressure - coal, oil and natural gas. When they are in weathering or as fuel burning, carbon oxidation is discharged into the atmosphere of carbon dioxide. Human consumption a large amount of mineral fuels have a significant impact on carbon cycle.
Carbon dioxide exchange carbon dioxide between the atmosphere and the ocean can be entered from the atmosphere, or the sea water can also enter the atmosphere. This exchange occurs at the interface of gas and water, strengthened due to the action of wind and waves. The amount of carbon dioxide flowing in these two directions is substantially equal. The amount of carbon dioxide in the atmosphere increases or decreases, and the amount of carbon dioxide absorbed in the ocean also increases or decreases. The formation of carbonaceous rocks and the decomposition of carbon dioxide in the atmosphere is dissolved in rainwater and groundwater into carbonated, and carbonates can transform limestones into soluble weight carbonates and are delivered to the ocean by rivers. The carbonate and heavy carbonate content in the seawater are saturated, and the newly input carbonate is received, and there is an equal amount of carbonate deposition. Through different rocking processes, it is formed as limestone, dolomite and carbonaceous shale. These rocks were destroyed under chemical and physical effects (weathered), and the carbon contained in the form of carbon dioxide into the atmosphere. Volcanic eruptions can also make the carbon in organic carbon and carbon in the carbon to the cycle of carbon. The damage of carbonaceous rocks is not much in the short period of time, but it is important to balance the cost of carbon in millions of years.
Intervention
Intervention of human activities to generate a large amount of carbon dioxide when the human burning mineral fuel is used to obtain energy. From 1949 to 1969, due to burning mineral fuels and other industrial activities, the amount of carbon dioxide was estimated to increase by 4.8% per year. As a result, the carbon dioxide concentration in the atmosphere increases. This destroys the original balance of nature, which may lead to abnormal climate. Mineral fuel combustion is generated and discharged into the atmosphere of carbon dioxide, which can be dissolved by seawater, but the increase in dissolved carbon dioxide in seawater will cause changes in acid and alkali balance and carbonate dissolution in seawater.
At the same time, if the industrial nitrogen is continuously growing, the increase in denitrification (also known as denitrification) is not able to keep up, then the global nitrogen cycle balance may be increasing The greater the pressure.