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98-456: In geography, location or place are used to denote a region (point, line, or area) on Earth's surface . The term location generally implies a higher degree of certainty than place , the latter often indicating an entity with an ambiguous boundary, relying more on human or social attributes of place identity and sense of place than on geometry. A populated place is called a settlement . A locality , settlement , or populated place

196-785: A Field Marshal or General of the Army (US five stars), or Generalissimo (Soviet Union); and in the US Armed Forces an Admiral (typically four stars) may also command a region. Due to the large size of this formation, its use is rarely employed. Some of the very few examples of an Army Region are each of the Eastern, Western, and southern (mostly in Italy) fronts in Europe during World War II . The military map unit symbol for this echelon of formation (see Military organization and APP-6A )

294-409: A cell wall . Newly dead animals may be covered by an exoskeleton . Fragmentation processes, which break through these protective layers, accelerate the rate of microbial decomposition. Animals fragment detritus as they hunt for food, as does passage through the gut. Freeze-thaw cycles and cycles of wetting and drying also fragment dead material. The chemical alteration of the dead organic matter

392-495: A food chain . Real systems are much more complex than this—organisms will generally feed on more than one form of food, and may feed at more than one trophic level. Carnivores may capture some prey that is part of a plant-based trophic system and others that are part of a detritus-based trophic system (a bird that feeds both on herbivorous grasshoppers and earthworms, which consume detritus). Real systems, with all these complexities, form food webs rather than food chains which present

490-619: A habitat . Ecosystem ecology is the "study of the interactions between organisms and their environment as an integrated system". The size of ecosystems can range up to ten orders of magnitude , from the surface layers of rocks to the surface of the planet. The Hubbard Brook Ecosystem Study started in 1963 to study the White Mountains in New Hampshire . It was the first successful attempt to study an entire watershed as an ecosystem. The study used stream chemistry as

588-609: A central role over a wide range, for example, in the slow development of soil from bare rock and the faster recovery of a community from disturbance . Disturbance also plays an important role in ecological processes. F. Stuart Chapin and coauthors define disturbance as "a relatively discrete event in time that removes plant biomass". This can range from herbivore outbreaks, treefalls, fires, hurricanes, floods, glacial advances , to volcanic eruptions . Such disturbances can cause large changes in plant, animal and microbe populations, as well as soil organic matter content. Disturbance

686-404: A country or the world having definable characteristics but not always fixed boundaries. In the fields of physical geography , ecology , biogeography , zoogeography , and environmental geography , regions tend to be based on natural features such as ecosystems or biotopes , biomes , drainage basins , natural regions , mountain ranges , soil types . Where human geography is concerned,

784-507: A critical role in global nutrient cycling and ecosystem function. Phosphorus enters ecosystems through weathering . As ecosystems age this supply diminishes, making phosphorus-limitation more common in older landscapes (especially in the tropics). Calcium and sulfur are also produced by weathering, but acid deposition is an important source of sulfur in many ecosystems. Although magnesium and manganese are produced by weathering, exchanges between soil organic matter and living cells account for

882-665: A cultural region. Examples of natural resource regions are the Rumaila Field , the oil field that lies along the border or Iraq and Kuwait and played a role in the Gulf War ; the Coal Region of Pennsylvania, which is a historical region as well as a cultural, physical, and natural resource region; the South Wales Coalfield , which like Pennsylvania's coal region is a historical, cultural, and natural region;

980-517: A faster recovery. More severe and more frequent disturbance result in longer recovery times. From one year to another, ecosystems experience variation in their biotic and abiotic environments. A drought , a colder than usual winter, and a pest outbreak all are short-term variability in environmental conditions. Animal populations vary from year to year, building up during resource-rich periods and crashing as they overshoot their food supply. Longer-term changes also shape ecosystem processes. For example,

1078-427: A function-based typology has been proposed to leverage the strengths of these different approaches into a unified system. Human activities are important in almost all ecosystems. Although humans exist and operate within ecosystems, their cumulative effects are large enough to influence external factors like climate. Ecosystems provide a variety of goods and services upon which people depend. Ecosystem goods include

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1176-416: A functional region. Nodal regions, functional urban regions, daily urban systems, local labour-market areas (LLMAs), or travel-to-work areas (TTWAs) are considered to be special instances of a general functional region that need to fulfil some specific conditions regarding, for instance, the character of the region-organising interaction or the presence of urban cores, (Halas et al., 2015 ). In military usage,

1274-698: A general level, for example, tropical forests , temperate grasslands , and arctic tundra . There can be any degree of subcategories among ecosystem types that comprise a biome, e.g., needle-leafed boreal forests or wet tropical forests. Although ecosystems are most commonly categorized by their structure and geography, there are also other ways to categorize and classify ecosystems such as by their level of human impact (see anthropogenic biome ), or by their integration with social processes or technological processes or their novelty (e.g. novel ecosystem ). Each of these taxonomies of ecosystems tends to emphasize different structural or functional properties. None of these

1372-536: A lesser degree, regions in the sphere of influence of Greater New England, "Acadia" (Nova Scotia), "Newfoundland and The Fishery/The Banks". Other examples of historical regions are Iroquoia, Ohio Country , Illinois Country , and Rupert's Land . In Russia , historical regions include Siberia and the Russian North , as well as the Ural Mountains . These regions had an identity that developed from

1470-672: A means of monitoring ecosystem properties, and developed a detailed biogeochemical model of the ecosystem. Long-term research at the site led to the discovery of acid rain in North America in 1972. Researchers documented the depletion of soil cations (especially calcium) over the next several decades. Ecosystems can be studied through a variety of approaches—theoretical studies, studies monitoring specific ecosystems over long periods of time, those that look at differences between ecosystems to elucidate how they work and direct manipulative experimentation. Studies can be carried out at

1568-528: A more important role in moving nutrients around. This can be especially important as the soil thaws in the spring, creating a pulse of nutrients that become available. Decomposition rates are low under very wet or very dry conditions. Decomposition rates are highest in wet, moist conditions with adequate levels of oxygen. Wet soils tend to become deficient in oxygen (this is especially true in wetlands ), which slows microbial growth. In dry soils, decomposition slows as well, but bacteria continue to grow (albeit at

1666-406: A number of common, non random properties in the topology of their network. The carbon and nutrients in dead organic matter are broken down by a group of processes known as decomposition. This releases nutrients that can then be re-used for plant and microbial production and returns carbon dioxide to the atmosphere (or water) where it can be used for photosynthesis. In the absence of decomposition,

1764-508: A number of countries have borrowed the term as the formal name for a type of subnational entity (e.g., the región , used in Chile ). In English, the word is also used as the conventional translation for equivalent terms in other languages (e.g., the область ( oblast ), used in Russia alongside a broader term регион ). The following countries use the term "region" (or its cognate ) as

1862-421: A process known as denitrification . Mycorrhizal fungi which are symbiotic with plant roots, use carbohydrates supplied by the plants and in return transfer phosphorus and nitrogen compounds back to the plant roots. This is an important pathway of organic nitrogen transfer from dead organic matter to plants. This mechanism may contribute to more than 70 Tg of annually assimilated plant nitrogen, thereby playing

1960-418: A region is shorthand for the name of a military formation larger than an Army Group and smaller than a Theater . The full name of the military formation is Army Region. The size of an Army Region can vary widely but is generally somewhere between about 1 million and 3 million soldiers. Two or more Army Regions could make up a Theater. An Army Region is typically commanded by a full General (US four stars),

2058-529: A significant percentage of their respective continental land area. To a large extent, major continental regions are mental constructs created by considering an efficient way to define large areas of the continents. For the most part, the images of the world are derived as much from academic studies, from all types of media, or from personal experience of global exploration . They are a matter of collective human knowledge of their own planet and are attempts to better understand their environments. Regional geography

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2156-696: A significant portion of ecosystem fluxes. Potassium is primarily cycled between living cells and soil organic matter. Biodiversity plays an important role in ecosystem functioning. Ecosystem processes are driven by the species in an ecosystem, the nature of the individual species, and the relative abundance of organisms among these species. Ecosystem processes are the net effect of the actions of individual organisms as they interact with their environment. Ecological theory suggests that in order to coexist, species must have some level of limiting similarity —they must be different from one another in some fundamental way, otherwise, one species would competitively exclude

2254-658: A similar way, as does Romania and Venezuela . The government of Singapore makes use of the term " region " for its own administrative purposes. The following countries use an administrative subdivision conventionally referred to as a region in English: China has five 自治区 ( zìzhìqū ) and two 特別行政區 (or 特别行政区; tèbiéxíngzhèngqū ), which are translated as " autonomous region " and " special administrative region ", respectively. There are many relatively small regions based on local government agencies such as districts, agencies, or regions. In general, they are all regions in

2352-408: A slower rate) even after soils become too dry to support plant growth. Ecosystems are dynamic entities. They are subject to periodic disturbances and are always in the process of recovering from past disturbances. When a perturbation occurs, an ecosystem responds by moving away from its initial state. The tendency of an ecosystem to remain close to its equilibrium state, despite that disturbance,

2450-464: A small effect on ecosystem function. Ecologically distinct species, on the other hand, have a much larger effect. Similarly, dominant species have a large effect on ecosystem function, while rare species tend to have a small effect. Keystone species tend to have an effect on ecosystem function that is disproportionate to their abundance in an ecosystem. An ecosystem engineer is any organism that creates, significantly modifies, maintains or destroys

2548-625: A sort of social and political polity . The term Muslim world is sometimes used to refer to the region of the world where Islam is dominant. These broad terms are somewhat vague when used to describe regions. Within some religions there are clearly defined regions. The Roman Catholic Church , the Church of England , the Eastern Orthodox Church , and others, define ecclesiastical regions with names such as diocese , eparchy , ecclesiastical provinces , and parish . For example,

2646-468: A variety of approaches—theoretical studies, studies monitoring specific ecosystems over long periods of time, those that look at differences between ecosystems to elucidate how they work and direct manipulative experimentation. Biomes are general classes or categories of ecosystems. However, there is no clear distinction between biomes and ecosystems. Ecosystem classifications are specific kinds of ecological classifications that consider all four elements of

2744-443: A variety of goods and services upon which people depend, and may be part of. Ecosystem goods include the "tangible, material products" of ecosystem processes such as water, food, fuel, construction material, and medicinal plants . Ecosystem services , on the other hand, are generally "improvements in the condition or location of things of value". These include things like the maintenance of hydrological cycles , cleaning air and water,

2842-522: A variety of scales, ranging from whole-ecosystem studies to studying microcosms or mesocosms (simplified representations of ecosystems). American ecologist Stephen R. Carpenter has argued that microcosm experiments can be "irrelevant and diversionary" if they are not carried out in conjunction with field studies done at the ecosystem scale. In such cases, microcosm experiments may fail to accurately predict ecosystem-level dynamics. Biomes are general classes or categories of ecosystems. However, there

2940-466: A way of describing spatial areas, the concept of regions is important and widely used among the many branches of geography, each of which can describe areas in regional terms. For example, ecoregion is a term used in environmental geography , cultural region in cultural geography , bioregion in biogeography , and so on. The field of geography that studies regions themselves is called regional geography . Regions are an area or division, especially part of

3038-454: Is a branch of geography that studies regions of all sizes across the Earth . It has a prevailing descriptive character. The main aim is to understand or define the uniqueness or character of a particular region, which consists of natural as well as human elements. Attention is paid also to regionalization, which covers the proper techniques of space delimitation into regions. Regional geography

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3136-431: Is a system that environments and their organisms form through their interaction. The biotic and abiotic components are linked together through nutrient cycles and energy flows. Ecosystems are controlled by external and internal factors . External factors such as climate , parent material which forms the soil and topography , control the overall structure of an ecosystem but are not themselves influenced by

3234-477: Is also considered as a certain approach to study in geographical sciences (similar to quantitative or critical geographies ; for more information, see history of geography ). Human geography is a branch of geography that focuses on the study of patterns and processes that shape human interaction with various discrete environments. It encompasses human , political , cultural , social , and economic aspects among others that are often clearly delineated. While

3332-458: Is an international synthesis by over 1000 of the world's leading biological scientists that analyzes the state of the Earth's ecosystems and provides summaries and guidelines for decision-makers. The report identified four major categories of ecosystem services: provisioning, regulating, cultural and supporting services. It concludes that human activity is having a significant and escalating impact on

3430-442: Is consumed by animals while still alive and enters the plant-based trophic system. After plants and animals die, the organic matter contained in them enters the detritus-based trophic system. Ecosystem respiration is the sum of respiration by all living organisms (plants, animals, and decomposers) in the ecosystem. Net ecosystem production is the difference between gross primary production (GPP) and ecosystem respiration. In

3528-714: Is currently a controversial proposal to divide the rest of Sweden into large regions , replacing the current counties. The government of the Philippines uses the term "region" (in Filipino , rehiyon ) when it is necessary to group provinces, the primary administrative subdivision of the country. This is also the case in Brazil , which groups its primary administrative divisions ( estados ; "states") into grandes regiões ( greater regions ) for statistical purposes, while Russia uses экономические районы ( economic regions ) in

3626-490: Is described as a displacement from another site. In simpler terms, relative location is where something is compared to another. Relative location is widely used for travelling and shipping because it helps people know where a place is compared to another. It does not have to be extremely specific, but enough that it is known where each place's absolute location is. For example, Singapore is in Southeast Asia, whilst

3724-569: Is followed by succession, a "directional change in ecosystem structure and functioning resulting from biotically driven changes in resource supply." The frequency and severity of disturbance determine the way it affects ecosystem function. A major disturbance like a volcanic eruption or glacial advance and retreat leave behind soils that lack plants, animals or organic matter. Ecosystems that experience such disturbances undergo primary succession . A less severe disturbance like forest fires, hurricanes or cultivation result in secondary succession and

3822-473: Is giving spatial understanding of mediated image. [REDACTED] Africa [REDACTED] Antarctica [REDACTED] Asia [REDACTED] Australia [REDACTED] Europe [REDACTED] North America [REDACTED] South America [REDACTED] Afro-Eurasia [REDACTED] Americas [REDACTED] Eurasia [REDACTED] Oceania Ecosystem An ecosystem (or ecological system )

3920-554: Is governed by three sets of factors—the physical environment (temperature, moisture, and soil properties), the quantity and quality of the dead material available to decomposers, and the nature of the microbial community itself. Temperature controls the rate of microbial respiration; the higher the temperature, the faster the microbial decomposition occurs. Temperature also affects soil moisture, which affects decomposition. Freeze-thaw cycles also affect decomposition—freezing temperatures kill soil microorganisms, which allows leaching to play

4018-421: Is identified with six Xs. Media geography is a spatio-temporal understanding, brought through different gadgets of media, nowadays, media became inevitable at different proportions and everyone supposed to consumed at different gravity. The spatial attributes are studied with the help of media outputs in shape of images which are contested in nature and pattern as well where politics is inseparable. Media geography

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4116-489: Is likely to have a well-defined name but a boundary that is not well defined, but rather varies by context. London , for instance, has a legal boundary, but this is unlikely to completely match with general usage. An area within a town, such as Covent Garden in London, also almost always has some ambiguity as to its extent. In geography, location is considered to be more precise than "place". A relative location, or situation,

4214-405: Is no clear distinction between biomes and ecosystems. Biomes are always defined at a very general level. Ecosystems can be described at levels that range from very general (in which case the names are sometimes the same as those of biomes) to very specific, such as "wet coastal needle-leafed forests". Biomes vary due to global variations in climate . Biomes are often defined by their structure: at

4312-432: Is not an abstract spatial concept, but to a certain extent it can be regarded as a reflection of the spatial behaviour of individuals in a geographic space. The functional region is conceived as a general concept while its inner structure, inner spatial flows, and interactions need not necessarily show any regular pattern, only selfcontainment. The concept of self-containment remains the only crucial defining characteristic of

4410-531: Is primarily achieved through bacterial and fungal action. Fungal hyphae produce enzymes that can break through the tough outer structures surrounding dead plant material. They also produce enzymes that break down lignin , which allows them access to both cell contents and the nitrogen in the lignin. Fungi can transfer carbon and nitrogen through their hyphal networks and thus, unlike bacteria, are not dependent solely on locally available resources. Decomposition rates vary among ecosystems. The rate of decomposition

4508-485: Is termed its resistance . The capacity of a system to absorb disturbance and reorganize while undergoing change so as to retain essentially the same function, structure, identity, and feedbacks is termed its ecological resilience . Resilience thinking also includes humanity as an integral part of the biosphere where we are dependent on ecosystem services for our survival and must build and maintain their natural capacities to withstand shocks and disturbances. Time plays

4606-422: Is the "best" classification. Ecosystem classifications are specific kinds of ecological classifications that consider all four elements of the definition of ecosystems : a biotic component, an abiotic complex, the interactions between and within them, and the physical space they occupy. Different approaches to ecological classifications have been developed in terrestrial, freshwater and marine disciplines, and

4704-826: The Grand Banks . He rejects regions traditionally used in describing American history, like New France , "West Indies", the Middle Colonies , and the individual colonies themselves ( Province of Maryland , for example). Instead he writes of "discrete colonization areas", which may be named after colonies but rarely adhere strictly to political boundaries. Among other historic regions of this type, he writes about "Greater New England" and its major sub-regions of "Plymouth", "New Haven shores" (including parts of Long Island), "Rhode Island" (or "Narragansett Bay"), "the Piscataqua", "Massachusetts Bay", "Connecticut Valley", and to

4802-554: The Kuznetsk Basin , a similarly important coal mining region in Russia; Kryvbas , the economic and iron ore mining region of Ukraine; and the James Bay Project , a large region of Quebec where one of the largest hydroelectric systems in the world has been developed. Sometimes a region associated with a religion is given a name, like Christendom , a term with medieval and renaissance connotations of Christianity as

4900-1057: The Metropolitan Water Reclamation District of Greater Chicago , the Las Vegas-Clark County Library District , the Metropolitan Police Service of Greater London , as well as other local districts like the York Rural Sanitary District , the Delaware River Port Authority , the Nassau County Soil and Water Conservation District , and C-TRAN . The traditional territorial divisions of some countries are also commonly rendered in English as "regions". These informal divisions do not form

4998-579: The Northwest European Atlantic Protestant Region , which includes sub-regions such as the "Western Channel Community", which itself is made of sub-regions such as the English West Country of Cornwall , Devon , Somerset , and Dorset . In describing historic regions of America, Meinig writes of "The Great Fishery" off the coast of Newfoundland and New England, an oceanic region that includes

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5096-602: The USA is in North America - a broad example of relative location. An absolute location can be designated using a specific pairing of latitude and longitude in a Cartesian coordinate grid (for example, a spherical coordinate system or an ellipsoid-based system such as the World Geodetic System ) or similar methods. For example, the position of New York City in the United States can be expressed using

5194-515: The United Kingdom 's Lake District and California's Wine Country . great plains region Natural resources often occur in distinct regions. Natural resource regions can be a topic of physical geography or environmental geography, but also have a strong element of human geography and economic geography. A coal region, for example, is a physical or geomorphological region, but its development and exploitation can make it into an economic and

5292-574: The equator . Because latitude and longitude are expressed relative to these lines, a position expressed in latitude and longitude is also a relative location. Region Apart from the global continental regions, there are also hydrospheric and atmospheric regions that cover the oceans , and discrete climates above the land and water masses of the planet. The land and water global regions are divided into subregions geographically bounded by large geological features that influence large-scale ecologies, such as plains and features. As

5390-555: The resource inputs are generally controlled by external processes like climate and parent material, the availability of these resources within the ecosystem is controlled by internal factors like decomposition, root competition or shading. Other factors like disturbance, succession or the types of species present are also internal factors. Primary production is the production of organic matter from inorganic carbon sources. This mainly occurs through photosynthesis . The energy incorporated through this process supports life on earth, while

5488-435: The "tangible, material products" of ecosystem processes such as water, food, fuel, construction material, and medicinal plants . They also include less tangible items like tourism and recreation, and genes from wild plants and animals that can be used to improve domestic species. Ecosystem services , on the other hand, are generally "improvements in the condition or location of things of value". These include things like

5586-643: The United States is divided into 32 Roman Catholic ecclesiastical provinces . The Lutheran Church–Missouri Synod is organized into 33 geographic districts , which are subdivided into circuits (the Atlantic District (LCMS) , for example). The Church of Jesus Christ of Latter-day Saints uses regions similar to dioceses and parishes, but uses terms like ward and stake . In the field of political geography , regions tend to be based on political units such as sovereign states ; subnational units such as administrative regions, provinces , states (in

5684-769: The United States) , counties , townships , territories , etc.; and multinational groupings, including formally defined units such as the European Union , the Association of Southeast Asian Nations , and NATO , as well as informally defined regions such as the Third World , Western Europe , and the Middle East. The word "region" is taken from the Latin regio (derived from regere , 'to rule'), and

5782-481: The absence of disturbance, net ecosystem production is equivalent to the net carbon accumulation in the ecosystem. Energy can also be released from an ecosystem through disturbances such as wildfire or transferred to other ecosystems (e.g., from a forest to a stream to a lake) by erosion . In aquatic systems , the proportion of plant biomass that gets consumed by herbivores is much higher than in terrestrial systems. In trophic systems, photosynthetic organisms are

5880-402: The amount of energy available to the ecosystem. Parent material determines the nature of the soil in an ecosystem, and influences the supply of mineral nutrients. Topography also controls ecosystem processes by affecting things like microclimate , soil development and the movement of water through a system. For example, ecosystems can be quite different if situated in a small depression on

5978-504: The amount of light available, the amount of leaf area a plant has to capture light (shading by other plants is a major limitation of photosynthesis), the rate at which carbon dioxide can be supplied to the chloroplasts to support photosynthesis, the availability of water, and the availability of suitable temperatures for carrying out photosynthesis. Energy and carbon enter ecosystems through photosynthesis, are incorporated into living tissue, transferred to other organisms that feed on

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6076-534: The area and suggest a coherent tourism experience to visitors. Countries, states, provinces, and other administrative regions are often carved up into tourism regions to facilitate attracting visitors. Some of the more famous tourism regions based on historical or current administrative regions include Tuscany in Italy and Yucatán in Mexico. Famous examples of regions created by a government or tourism bureau include

6174-578: The basis of the modern administrative divisions of these countries, but still define and delimit local regional identity and sense of belonging. Examples are: Functional regions are usually understood to be the areas organised by the horizontal functional relations (flows, interactions) that are maximised within a region and minimised across its borders so that the principles of internal cohesiveness and external separation regarding spatial interactions are met (see, for instance, Farmer and Fotheringham, 2011; Klapka, Halas, 2016; Smart, 1974 ). A functional region

6272-408: The carbon makes up much of the organic matter in living and dead biomass, soil carbon and fossil fuels . It also drives the carbon cycle , which influences global climate via the greenhouse effect . Through the process of photosynthesis, plants capture energy from light and use it to combine carbon dioxide and water to produce carbohydrates and oxygen . The photosynthesis carried out by all

6370-432: The combustion of fossil fuels, ammonia gas which evaporates from agricultural fields which have had fertilizers applied to them, and dust. Anthropogenic nitrogen inputs account for about 80% of all nitrogen fluxes in ecosystems. When plant tissues are shed or are eaten, the nitrogen in those tissues becomes available to animals and microbes. Microbial decomposition releases nitrogen compounds from dead organic matter in

6468-418: The concept to draw attention to the importance of transfers of materials between organisms and their environment. He later refined the term, describing it as "The whole system, ... including not only the organism-complex, but also the whole complex of physical factors forming what we call the environment". Tansley regarded ecosystems not simply as natural units, but as "mental isolates". Tansley later defined

6566-467: The coordinate system as the location 40.7128°N (latitude), 74.0060°W ( Absolute locations are also relative locations, since even absolute locations are expressed relative to something else. For example, longitude is the number of degrees east or west of the Prime Meridian , a line arbitrarily chosen to pass through Greenwich , England. Similarly, latitude is the number of degrees north or south of

6664-403: The dead organic matter would accumulate in an ecosystem, and nutrients and atmospheric carbon dioxide would be depleted. Decomposition processes can be separated into three categories— leaching , fragmentation and chemical alteration of dead material. As water moves through dead organic matter, it dissolves and carries with it the water-soluble components. These are then taken up by organisms in

6762-447: The definition of ecosystems : a biotic component, an abiotic complex, the interactions between and within them, and the physical space they occupy. Biotic factors of the ecosystem are living things; such as plants, animals, and bacteria, while abiotic are non-living components; such as water, soil and atmosphere. Plants allow energy to enter the system through photosynthesis , building up plant tissue. Animals play an important role in

6860-435: The early modern period and led to Siberian regionalism . A tourism region is a geographical region that has been designated by a governmental organization or tourism bureau as having common cultural or environmental characteristics. These regions are often named after a geographical, former, or current administrative region or may have a name created for tourism purposes. The names often evoke certain positive qualities of

6958-655: The ecosystem or to gradual disruption of biotic processes and degradation of abiotic conditions of the ecosystem. Once the original ecosystem has lost its defining features, it is considered "collapsed ". Ecosystem restoration can contribute to achieving the Sustainable Development Goals . An ecosystem (or ecological system) consists of all the organisms and the abiotic pools (or physical environment) with which they interact. The biotic and abiotic components are linked together through nutrient cycles and energy flows. "Ecosystem processes" are

7056-528: The ecosystem. Internal factors are controlled, for example, by decomposition , root competition, shading, disturbance, succession, and the types of species present. While the resource inputs are generally controlled by external processes, the availability of these resources within the ecosystem is controlled by internal factors. Therefore, internal factors not only control ecosystem processes but are also controlled by them. Ecosystems are dynamic entities—they are subject to periodic disturbances and are always in

7154-421: The flow of energy through a lake was the primary driver of the ecosystem. Hutchinson's students, brothers Howard T. Odum and Eugene P. Odum , further developed a "systems approach" to the study of ecosystems. This allowed them to study the flow of energy and material through ecological systems. Ecosystems are controlled by both external and internal factors. External factors, also called state factors, control

7252-458: The forests of eastern North America still show legacies of cultivation which ceased in 1850 when large areas were reverted to forests. Another example is the methane production in eastern Siberian lakes that is controlled by organic matter which accumulated during the Pleistocene . Ecosystems continually exchange energy and carbon with the wider environment . Mineral nutrients, on

7350-580: The general sense of being bounded spatial units. Examples include electoral districts such as Washington's 6th congressional district and Tennessee's 1st congressional district ; school districts such as Granite School District and Los Angeles Unified School District ; economic districts such as the Reedy Creek Improvement District ; metropolitan areas such as the Seattle metropolitan area , and metropolitan districts such as

7448-691: The landscape, versus one present on an adjacent steep hillside. Other external factors that play an important role in ecosystem functioning include time and potential biota , the organisms that are present in a region and could potentially occupy a particular site. Ecosystems in similar environments that are located in different parts of the world can end up doing things very differently simply because they have different pools of species present. The introduction of non-native species can cause substantial shifts in ecosystem function. Unlike external factors, internal factors in ecosystems not only control ecosystem processes but are also controlled by them. While

7546-399: The largest of water regions known as oceans . There are also significant regions that do not belong to either classification, such as archipelago regions that are littoral regions, or earthquake regions that are defined in geology . Continental regions are usually based on broad experiences in human history and attempt to reduce very large areas to more manageable regionalization for

7644-423: The living and dead plant matter, and eventually released through respiration. The carbon and energy incorporated into plant tissues (net primary production) is either consumed by animals while the plant is alive, or it remains uneaten when the plant tissue dies and becomes detritus . In terrestrial ecosystems , the vast majority of the net primary production ends up being broken down by decomposers . The remainder

7742-408: The maintenance of hydrological cycles, cleaning air and water, the maintenance of oxygen in the atmosphere, crop pollination and even things like beauty, inspiration and opportunities for research. While material from the ecosystem had traditionally been recognized as being the basis for things of economic value, ecosystem services tend to be taken for granted. The Millennium Ecosystem Assessment

7840-405: The maintenance of oxygen in the atmosphere, crop pollination and even things like beauty, inspiration and opportunities for research. Many ecosystems become degraded through human impacts, such as soil loss , air and water pollution , habitat fragmentation , water diversion , fire suppression , and introduced species and invasive species . These threats can lead to abrupt transformation of

7938-432: The major focus of human geography is not the physical landscape of the Earth (see physical geography ), it is hardly possible to discuss human geography without referring to the physical landscape on which human activities are being played out, and environmental geography is emerging as a link between the two. Regions of human geography can be divided into many broad categories: The field of historical geography involves

8036-433: The movement of matter and energy through the system, by feeding on plants and on one another. They also influence the quantity of plant and microbial biomass present. By breaking down dead organic matter , decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be readily used by plants and microbes. Ecosystems provide

8134-604: The name of a type of subnational administrative unit: The Canadian province of Québec also uses the "administrative region" ( région administrative ). Scotland had local government regions from 1975 to 1996. In Spain the official name of the autonomous community of Murcia is Región de Murcia . Also, some single-province autonomous communities such as Madrid use the term región interchangeably with comunidad autónoma . Two län (counties) in Sweden are officially called 'regions': Skåne and Västra Götaland , and there

8232-537: The other hand, are mostly cycled back and forth between plants, animals, microbes and the soil. Most nitrogen enters ecosystems through biological nitrogen fixation , is deposited through precipitation, dust, gases or is applied as fertilizer . Most terrestrial ecosystems are nitrogen-limited in the short term making nitrogen cycling an important control on ecosystem production. Over the long term, phosphorus availability can also be critical. Macronutrients which are required by all plants in large quantities include

8330-509: The other. Despite this, the cumulative effect of additional species in an ecosystem is not linear: additional species may enhance nitrogen retention, for example. However, beyond some level of species richness, additional species may have little additive effect unless they differ substantially from species already present. This is the case for example for exotic species . The addition (or loss) of species that are ecologically similar to those already present in an ecosystem tends to only have

8428-403: The overall structure of an ecosystem and the way things work within it, but are not themselves influenced by the ecosystem. On broad geographic scales, climate is the factor that "most strongly determines ecosystem processes and structure". Climate determines the biome in which the ecosystem is embedded. Rainfall patterns and seasonal temperatures influence photosynthesis and thereby determine

8526-405: The plants in an ecosystem is called the gross primary production (GPP). About half of the gross GPP is respired by plants in order to provide the energy that supports their growth and maintenance. The remainder, that portion of GPP that is not used up by respiration, is known as the net primary production (NPP). Total photosynthesis is limited by a range of environmental factors. These include

8624-585: The primary nutrients (which are most limiting as they are used in largest amounts): Nitrogen, phosphorus, potassium. Secondary major nutrients (less often limiting) include: Calcium, magnesium, sulfur. Micronutrients required by all plants in small quantities include boron, chloride, copper, iron, manganese, molybdenum, zinc. Finally, there are also beneficial nutrients which may be required by certain plants or by plants under specific environmental conditions: aluminum, cobalt, iodine, nickel, selenium, silicon, sodium, vanadium. Until modern times, nitrogen fixation

8722-413: The primary producers. The organisms that consume their tissues are called primary consumers or secondary producers — herbivores . Organisms which feed on microbes ( bacteria and fungi ) are termed microbivores . Animals that feed on primary consumers— carnivores —are secondary consumers. Each of these constitutes a trophic level. The sequence of consumption—from plant to herbivore, to carnivore—forms

8820-419: The process of recovering from some past disturbance. The tendency of an ecosystem to remain close to its equilibrium state, despite that disturbance, is termed its resistance . The capacity of a system to absorb disturbance and reorganize while undergoing change so as to retain essentially the same function, structure, identity, and feedbacks is termed its ecological resilience . Ecosystems can be studied through

8918-521: The purpose of the study. As such they are conceptual constructs, usually lacking distinct boundaries. The oceanic division into maritime regions is used in conjunction with the relationship to the central area of the continent, using directions of the compass . Some continental regions are defined by the major continental feature of their identity, such as the Amazon basin , or the Sahara , which both occupy

9016-442: The regions and subregions are described by the discipline of ethnography . Global regions are distinguishable from space, and are therefore clearly distinguished by the two basic terrestrial environments, land and water . However, they have been generally recognized as such much earlier by terrestrial cartography because of their impact on human geography. They are divided into the largest of land regions, known as continents and

9114-611: The soil, react with mineral soil, or are transported beyond the confines of the ecosystem (and are considered lost to it). Newly shed leaves and newly dead animals have high concentrations of water-soluble components and include sugars , amino acids and mineral nutrients. Leaching is more important in wet environments and less important in dry ones. Fragmentation processes break organic material into smaller pieces, exposing new surfaces for colonization by microbes. Freshly shed leaf litter may be inaccessible due to an outer layer of cuticle or bark , and cell contents are protected by

9212-511: The soil, where plants, fungi, and bacteria compete for it. Some soil bacteria use organic nitrogen-containing compounds as a source of carbon, and release ammonium ions into the soil. This process is known as nitrogen mineralization . Others convert ammonium to nitrite and nitrate ions, a process known as nitrification . Nitric oxide and nitrous oxide are also produced during nitrification. Under nitrogen-rich and oxygen-poor conditions, nitrates and nitrites are converted to nitrogen gas ,

9310-483: The spatial extent of ecosystems using the term " ecotope ". G. Evelyn Hutchinson , a limnologist who was a contemporary of Tansley's, combined Charles Elton 's ideas about trophic ecology with those of Russian geochemist Vladimir Vernadsky . As a result, he suggested that mineral nutrient availability in a lake limited algal production . This would, in turn, limit the abundance of animals that feed on algae. Raymond Lindeman took these ideas further to suggest that

9408-425: The study of human history as it relates to places and regions , or the study of how places and regions have changed over time. D. W. Meinig , a historical geographer of America, describes many historical regions in his book The Shaping of America: A Geographical Perspective on 500 Years of History . For example, in identifying European "source regions" in early American colonization efforts, he defines and describes

9506-421: The transfers of energy and materials from one pool to another. Ecosystem processes are known to "take place at a wide range of scales". Therefore, the correct scale of study depends on the question asked. The term "ecosystem" was first used in 1935 in a publication by British ecologist Arthur Tansley . The term was coined by Arthur Roy Clapham , who came up with the word at Tansley's request. Tansley devised

9604-679: Was the major source of nitrogen for ecosystems. Nitrogen-fixing bacteria either live symbiotically with plants or live freely in the soil. The energetic cost is high for plants that support nitrogen-fixing symbionts—as much as 25% of gross primary production when measured in controlled conditions. Many members of the legume plant family support nitrogen-fixing symbionts. Some cyanobacteria are also capable of nitrogen fixation. These are phototrophs , which carry out photosynthesis. Like other nitrogen-fixing bacteria, they can either be free-living or have symbiotic relationships with plants. Other sources of nitrogen include acid deposition produced through

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