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PI Curve
The PI (or photosynthesis-irradiance) curve is a graphical representation of the empirical relationship between solar irradiance and photosynthesis. A derivation of the Michaelis–Menten curve, it shows the generally positive correlation between light intensity and photosynthetic rate. It is a plot of photosynthetic rate as a function of light intensity (irradiance). Introduction The PI curve can be applied to terrestrial and marine reactions but is most commonly used to explain ocean-dwelling phytoplankton's photosynthetic response to changes in light intensity. Using this tool to approximate biological productivity is important because phytoplankton contribute ~50%Field et al. 1998 ''Primary production of the biosphere: integrating terrestrial and oceanic components,'' Science, 1998 Jul 10; 281(5374):237-40. doi: 10.1126/science.281.5374.237 of total global carbon fixation and are important suppliers to the marine food web. Within the scientific community, the curve can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosynthesis-irradiance Curve
The PI (or photosynthesis-irradiance) curve is a graphical representation of the empirical relationship between solar irradiance and photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in .... A derivation of the Michaelis–Menten curve, it shows the generally positive correlation between light intensity and photosynthetic rate. It is a plot of photosynthetic rate as a function of light intensity (irradiance). Introduction The PI curve can be applied to terrestrial and marine reactions but is most commonly used to explain ocean-dwelling phytoplankton's photosynthetic response to changes in light intensity. Using this tool to approximate biological productivity is important because phytoplankton contribute ~50%Field et al. 1998 ''Primary production of the biosphere: integ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Irradiance
Solar irradiance is the power per unit area ( surface power density) received from the Sun in the form of electromagnetic radiation in the wavelength range of the measuring instrument. Solar irradiance is measured in watts per square metre (W/m2) in SI units. Solar irradiance is often integrated over a given time period in order to report the radiant energy emitted into the surrounding environment (joule per square metre, J/m2) during that time period. This integrated solar irradiance is called solar irradiation, solar exposure, solar insolation, or insolation. Irradiance may be measured in space or at the Earth's surface after atmospheric absorption and scattering. Irradiance in space is a function of distance from the Sun, the solar cycle, and cross-cycle changes.Michael Boxwell, ''Solar Electricity Handbook: A Simple, Practical Guide to Solar Energy'' (2012), p. 41–42. Irradiance on the Earth's surface additionally depends on the tilt of the measuring surface, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosynthesis
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in carbohydrate molecules, such as sugars and starches, which are synthesized from carbon dioxide and water – hence the name ''photosynthesis'', from the Greek ''phōs'' (), "light", and ''synthesis'' (), "putting together". Most plants, algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies most of the energy necessary for life on Earth. Although photosynthesis is performed differently by different species, the process always begins when energy from light is absorbed by proteins called reaction centers that contain green chlorophyll (and other colored) pigments/chromophor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoinhibition
Photoinhibition is light-induced reduction in the photosynthetic capacity of a plant, alga, or cyanobacterium. Photosystem II (PSII) is more sensitive to light than the rest of the photosynthetic machinery, and most researchers define the term as light-induced damage to PSII. In living organisms, photoinhibited PSII centres are continuously repaired via degradation and synthesis of the D1 protein of the photosynthetic reaction center of PSII. Photoinhibition is also used in a wider sense, as dynamic photoinhibition, to describe all reactions that decrease the efficiency of photosynthesis when plants are exposed to light. History The first measurements of photoinhibition were published in 1956 by Bessel Kok. Even in the very first studies, it was obvious that plants have a repair mechanism that continuously repairs photoinhibitory damage. In 1966, Jones and Kok measured the action spectrum of photoinhibition and found that ultraviolet light is highly photoinhibitory. The visible- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PI Curve Chalker Et Al 1983
The number (; spelled out as "pi") is a mathematical constant that is the ratio of a circle's circumference to its diameter, approximately equal to 3.14159. The number appears in many formulas across mathematics and physics. It is an irrational number, meaning that it cannot be expressed exactly as a ratio of two integers, although fractions such as \tfrac are commonly Approximations of π, used to approximate it. Consequently, its decimal representation never ends, nor repeating decimal, enters a permanently repeating pattern. It is a transcendental number, meaning that it cannot be a solution of an equation (mathematics), equation involving only sums, products, powers, and integers. The transcendence of implies that it is impossible to solve the ancient challenge of squaring the circle with a Compass-and-straightedge construction, compass and straightedge. The decimal digits of appear to be random sequence, randomly distributed, but no proof of this conjecture has been fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytoplankton Bloom
An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in freshwater or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ''algae'' encompasses many types of aquatic photosynthetic organisms, both macroscopic multicellular organisms like seaweed and microscopic unicellular organisms like cyanobacteria. ''Algal bloom'' commonly refers to the rapid growth of microscopic unicellular algae, not macroscopic algae. An example of a macroscopic algal bloom is a kelp forest. Algal blooms are the result of a nutrient, like nitrogen or phosphorus from various sources (for example fertilizer runoff or other forms of nutrient pollution), entering the aquatic system and causing excessive growth of algae. An algal bloom affects the whole ecosystem. Consequences range from the benign feeding of higher trophic levels to more harmful effects like blocking sunlight from reaching other organis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Processes
Biological processes are those processes that are vital for an organism to live, and that shape its capacities for interacting with its environment. Biological processes are made of many chemical reactions or other events that are involved in the persistence and transformation of life forms. Metabolism and homeostasis are examples. Biological processes within an organism can also work as bioindicators. Scientists are able to look at an individual's biological processes to monitor the effects of environmental changes. Regulation of biological processes occurs when any process is modulated in its frequency, rate or extent. Biological processes are regulated by many means; examples include the control of gene expression, protein modification or interaction with a protein or substrate molecule. * Homeostasis: regulation of the internal environment to maintain a constant state; for example, sweating to reduce temperature * Organization: being structurally composed of one or more cells ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cellular Respiration
Cellular respiration is the process by which biological fuels are oxidised in the presence of an inorganic electron acceptor such as oxygen to produce large amounts of energy, to drive the bulk production of ATP. Cellular respiration may be described as a set of metabolic reactions and processes that take place in the cells of organisms to convert chemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. The reactions involved in respiration are catabolic reactions, which break large molecules into smaller ones, releasing energy. Respiration is one of the key ways a cell releases chemical energy to fuel cellular activity. The overall reaction occurs in a series of biochemical steps, some of which are redox reactions. Although cellular respiration is technically a combustion reaction, it is an unusual one because of the slow, controlled release of energy from the series of reactions. Nutrients that are commonly used by animal and pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metabolism
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the conversion of food to building blocks for proteins, lipids, nucleic acids, and some carbohydrates; and the elimination of metabolic wastes. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. The word metabolism can also refer to the sum of all chemical reactions that occur in living organisms, including digestion and the transportation of substances into and between different cells, in which case the above described set of reactions within the cells is called intermediary (or intermediate) metabolism. Metabolic reactions may be categorized as '' catabolic'' – the ''breaking down'' of compounds (for example, of glucose to pyruv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
