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108-402: The largest lake in the very water-based region is Lake Päijänne (1,080 km). Other large lakes are Lake Keitele (490 km2), Lake Konnevesi (190 km) and Lake Kivijärvi (150 km). The highest point in the region is Kiiskilänmäki in the municipality of Multia , which reaches an altitude of 269 meters above sea level. Kuokanjoki , Finland's shortest river and one of the world's shortest rivers

216-465: A cave . They have been important to humans as a place of shelter since the dawn of humanity. Craters are depressions in the ground, but unlike caves, they do not provide shelter or extend underground . There are many kinds of craters, such as impact craters , volcanic calderas , and isostatic depressions . Karst processes can create both solution caves , the most frequent cave type, and craters, as seen in karst sinkholes . The pedosphere

324-434: A habitat refers to the environment where a given species or population of organisms lives. Biomes may span more than one continent, and contain a variety of ecosystems and habitats. Land plants evolved from green algae , and are called embryophytes . They include trees , shrubs , ferns , grass , moss , and flowers . Most plants are vascular plants , meaning that their tissues distribute water and minerals throughout

432-409: A body of water from 2 hectares (5 acres) to 8 hectares (20 acres). Pioneering animal ecologist Charles Elton regarded lakes as waterbodies of 40 hectares (99 acres) or more. The term lake is also used to describe a feature such as Lake Eyre , which is a dry basin most of the time but may become filled under seasonal conditions of heavy rainfall. In common usage, many lakes bear names ending with

540-623: A coastline may be impacted by the tides , caused by changes in gravitational forces on larger bodies of water. Coasts are important zones in natural ecosystems, often home to a wide range of biodiversity . On land, they harbour important ecosystems such as freshwater or estuarine wetlands , which are important for bird populations and other terrestrial animals. In wave-protected areas they harbor saltmarshes , mangroves or seagrasses , all of which can provide nursery habitat for finfish, shellfish , and other aquatic species. Rocky shores are usually found along exposed coasts and provide habitat for

648-500: A comprehensive analysis of the origin of lakes and proposed what is a widely accepted classification of lakes according to their origin. This classification recognizes 11 major lake types that are divided into 76 subtypes. The 11 major lake types are: Tectonic lakes are lakes formed by the deformation and resulting lateral and vertical movements of the Earth's crust. These movements include faulting, tilting, folding, and warping. Some of

756-402: A form of organic lake. They form where a buildup of partly decomposed plant material in a wet environment leaves the vegetated surface below the water table for a sustained period of time. They are often low in nutrients and mildly acidic, with bottom waters low in dissolved oxygen. Artificial lakes or anthropogenic lakes are large waterbodies created by human activity . They can be formed by

864-540: A habitat for soil organisms , a recycling system for nutrients and organic wastes , a regulator of water quality , a modifier of atmospheric composition , and a medium for plant growth , making it a critically important provider of ecosystem services . Since soil has a tremendous range of available niches and habitats , it contains a prominent part of the Earth's genetic diversity . A gram of soil can contain billions of organisms, belonging to thousands of species, mostly microbial and largely still unexplored. Soil

972-538: A higher perimeter to area ratio than other lake types. These form where sediment from a tributary blocks the main river. These form where sediment from the main river blocks a tributary, usually in the form of a levee . Lakes formed by other processes responsible for floodplain basin creation. During high floods they are flushed with river water. There are four types: 1. Confluent floodplain lake, 2. Contrafluent-confluent floodplain lake, 3. Contrafluent floodplain lake, 4. Profundal floodplain lake. A solution lake

1080-510: A hypolimnion; accordingly, very shallow lakes are excluded from this classification system. Based upon their thermal stratification, lakes are classified as either holomictic , with a uniform temperature and density from top to bottom at a given time of year, or meromictic , with layers of water of different temperature and density that do not intermix. The deepest layer of water in a meromictic lake does not contain any dissolved oxygen so there are no living aerobic organisms . Consequently,

1188-428: A lake consists of a large area of standing water that occupies an extensive closed depression in limestone, it is also called a karst lake . Smaller solution lakes that consist of a body of standing water in a closed depression within a karst region are known as karst ponds. Limestone caves often contain pools of standing water, which are known as underground lakes . Classic examples of solution lakes are abundant in

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1296-455: A large area, it can influence climate and weather patterns. The terrain of a region largely determines its suitability for human settlement: flatter alluvial plains tend to have better farming soils than steeper, rockier uplands. Elevation is defined as the vertical distance between an object and sea level, while altitude is defined as the vertical distance from an object to Earth's surface. The elevation of Earth's land surface varies from

1404-491: A large elevation difference between the highest and lowest points would be deemed "high relief". Most land has relatively low relief. The change in elevation between two points of the terrain is called a slope or gradient. A topographic map is a form of terrain cartography which depicts terrain in terms of its elevation, slope, and the orientation of its landforms. It has prominent contour lines , which connect points of similar elevation, while perpendicular slope lines point in

1512-470: A large number of studies agree that small ponds are much more abundant than large lakes. For example, one widely cited study estimated that Earth has 304 million lakes and ponds, and that 91% of these are 1 hectare (2.5 acres) or less in area. Despite the overwhelming abundance of ponds, almost all of Earth's lake water is found in fewer than 100 large lakes; this is because lake volume scales superlinearly with lake area. Extraterrestrial lakes exist on

1620-539: A long time to cause noticeable changes in the landscape—for example, the Grand Canyon was created over the past 70 million years by the Colorado River , which scientists estimate continues to erode the canyon at a rate of 0.3 meters (1 foot) every 200 years. However, humans have caused erosion to be 10–40 times faster than normal, causing half the topsoil of the surface of Earth's land to be lost within

1728-489: A natural outflow and lose water solely by evaporation or underground seepage, or both. These are termed endorheic lakes. Many lakes are artificial and are constructed for hydroelectric power generation, aesthetic purposes, recreational purposes, industrial use, agricultural use, or domestic water supply . The number of lakes on Earth is undetermined because most lakes and ponds are very small and do not appear on maps or satellite imagery . Despite this uncertainty,

1836-499: A regional administrative unit of the state. The Central Finland covers almost the same geographical area as the former Central Finland Province. At that time, the province of Central Finland was merged with the provinces of Turku and Pori and Vaasa and the northern parts of Tavastia to form the Western Finland Province . The current Central Finland is larger than the former province of Central Finland, as Jämsä

1944-403: A result of meandering. The slow-moving river forms a sinuous shape as the outer side of bends are eroded away more rapidly than the inner side. Eventually a horseshoe bend is formed and the river cuts through the narrow neck. This new passage then forms the main passage for the river and the ends of the bend become silted up, thus forming a bow-shaped lake. Their crescent shape gives oxbow lakes

2052-535: A result of the 1959 Hebgen Lake earthquake . Most landslide lakes disappear in the first few months after formation, but a landslide dam can burst suddenly at a later stage and threaten the population downstream when the lake water drains out. In 1911, an earthquake triggered a landslide that blocked a deep valley in the Pamir Mountains region of Tajikistan , forming the Sarez Lake . The Usoi Dam at

2160-518: A role in the regional and global climate. Densely populated cities are warmer and create urban heat islands that have effects on the precipitation, cloud cover , and temperature of the region. A landform is a natural or manmade land feature. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography . Landforms include hills , mountains , canyons , and valleys , as well as shoreline features such as bays , capes , and peninsulas . The shoreline

2268-421: A set of practices called sustainable land management . A biome is an area "characterized by its vegetation, soil, climate, and wildlife ." There are five major types of biomes on land: grasslands, forests, deserts, tundras, and freshwater. Other types of biomes include shrublands, wetlands, and polar ice caps . An ecosystem refers to the interaction between organisms within a particular environment, and

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2376-746: A solid phase of minerals and organic matter (the soil matrix), as well as a porous phase that holds gases (the soil atmosphere) and water (the soil solution). Accordingly, soil is a three- state system of solids, liquids, and gases. Soil is a product of several factors: the influence of climate , relief (elevation, orientation, and slope of terrain), organisms, and the soil's parent materials (original minerals) interacting over time. It continually undergoes development by way of numerous physical, chemical and biological processes, which include weathering and erosion . Given its complexity and strong internal connectedness , soil ecologists regard soil as an ecosystem . Soil acts as an engineering medium,

2484-455: A steady growth to the present-day forms or, more likely, a rapid growth early in Earth history followed by a long-term steady continental area. Continents are formed by plate tectonics , a process ultimately driven by the continuous loss of heat from the Earth's interior. On time scales lasting hundreds of millions of years, the supercontinents have formed and broken apart three times. Roughly 750  mya (million years ago), one of

2592-422: A variation in density because of thermal gradients. Stratification can also result from a density variation caused by gradients in salinity. In this case, the hypolimnion and epilimnion are separated not by a thermocline but by a halocline , which is sometimes referred to as a chemocline . Lakes are informally classified and named according to the seasonal variation in their lake level and volume. Some of

2700-433: A wide range of sessile animals (e.g. mussels , starfish , barnacles ) and various kinds of seaweeds . Along tropical coasts with clear, nutrient-poor water, coral reefs can often be found between depths of 1–50 meters (3.3–164.0 feet). According to a United Nations atlas, 44% of all people live within 150 km (93 mi) of the sea. Because of their importance in society and high concentration of population,

2808-443: Is sag ponds . Volcanic lakes are lakes that occupy either local depressions, e.g. craters and maars , or larger basins, e.g. calderas , created by volcanism . Crater lakes are formed in volcanic craters and calderas, which fill up with precipitation more rapidly than they empty via either evaporation, groundwater discharge, or a combination of both. Sometimes the latter are called caldera lakes, although often no distinction

2916-403: Is a lake occupying a basin formed by surface dissolution of bedrock. In areas underlain by soluble bedrock, its solution by precipitation and percolating water commonly produce cavities. These cavities frequently collapse to form sinkholes that form part of the local karst topography . Where groundwater lies near the grounds surface, a sinkhole will be filled water as a solution lake. If such

3024-442: Is a major component of the Earth's ecosystem. The world's ecosystems are impacted in far-reaching ways by the processes carried out in the soil, with effects ranging from ozone depletion and global warming to rainforest destruction and water pollution . With respect to Earth's carbon cycle , soil acts as an important carbon reservoir , and it is potentially one of the most reactive to human disturbance and climate change. As

3132-470: Is a reasonably sharp contrast between the more felsic upper continental crust and the lower continental crust, which is more mafic in character. The composition of land is not uniform across the Earth, varying between locations and between strata within the same location. The most prominent components of upper continental crust include silicon dioxide , aluminium oxide , and magnesium . The continental crust consists of lower density material such as

3240-442: Is also used in wetland ecology, where "upland" plants indicate an area that is not a wetland. In addition, the term moorland refers to upland shrubland biomes with acidic soils, while heathlands are lowland shrublands with acidic soils. Geomorphology refers to the study of the natural processes that shape land's surface, creating landforms. Erosion and tectonics , volcanic eruptions , flooding , weathering , glaciation ,

3348-529: Is also used more generally, as in Persian rigestân ( ریگستان ) "place of sand, desert", golestân ( گلستان ) "place of flowers, garden", gurestân ( گورستان ) "graveyard, cemetery", and Hindustân ( هندوستان ) "land of the Indo people". The study of land and its history in general is called geography . Mineralogy is the study of minerals, and petrology is the study of rocks. Soil science

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3456-488: Is an island , and a chain of islands is an archipelago . The smaller the island, the larger the percentage of its land area will be adjacent to the water, and subsequently will be coast or beach. Islands can be formed by a variety of processes. The Hawaiian islands , for example, even though they are not near a plate boundary, formed from isolated volcanic activity . Atolls are ring-shaped islands made of coral , created when subsidence causes an island to sink beneath

3564-644: Is called the shoreline . The word land is derived from Old English , from the Proto-Germanic word * landą , "untilled land", and then the Proto-Indo-European * lendʰ- , especially in northern regions that were home to languages like Proto-Celtic and Proto-Slavic . Examples include Old Irish land , "land, plot, church building" and Old Irish ithlann , "threshing floor", and Old East Slavic ljadina "wasteland, weeds". A country or nation may be referred to as

3672-468: Is dammed behind an ice shelf that is attached to the coastline. They are mostly found in Antarctica. Fluvial (or riverine) lakes are lakes produced by running water. These lakes include plunge pool lakes , fluviatile dams and meander lakes. The most common type of fluvial lake is a crescent-shaped lake called an oxbow lake due to the distinctive curved shape. They can form in river valleys as

3780-521: Is in the region. Central Finland has been one of the slowly growing regions in terms of population, but the growth has been based on the Jyväskylä sub-region 's position as a significant growth center, and most of the region's municipalities are declining in population. Also, of these, Kyyjärvi has landed on the Finnish state's crisis financial management list due to its economic hardship. Luhanka ,

3888-452: Is made. An example is Crater Lake in Oregon , in the caldera of Mount Mazama . The caldera was created in a massive volcanic eruption that led to the subsidence of Mount Mazama around 4860 BCE. Other volcanic lakes are created when either rivers or streams are dammed by lava flows or volcanic lahars . The basin which is now Malheur Lake , Oregon was created when a lava flow dammed

3996-418: Is often defined as the solid, dry surface of Earth. The word land may also collectively refer the collective natural resources of Earth, including its land cover , rivers , shallow lakes , its biosphere , the lowest layer of the atmosphere ( troposphere ), groundwater reserves, and the physical results of human activity on land, such as architecture and agriculture. The boundary between land and sea

4104-459: Is pushed upwards, or subductional events, where Earth's crust is pushed into the mantle, causing the crust to melt, rise due to its low density, and solidify into hardened rock, thickening the crust. A plateau , also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side, creating steep cliffs or escarpments . Both volcanic activity such as

4212-448: Is the interface between the land and the ocean . It migrates each day as tides rise and fall, and moves over long periods of time as sea levels change. The shore extends from the low tide line to the highest elevation that can be reached by storm waves, and the coast stretches out inland until the point where ocean-related features are no longer found. When land is in contact with bodies of water, it can be eroded. The weathering of

4320-399: Is the outermost layer of Earth's continental surface and is composed of soil and subject to soil formation processes . Below it, the lithosphere encompasses both Earth's crust and the uppermost layer of the mantle . The lithosphere rests, or "floats", on top of the mantle below it via isostasy . Above the solid ground, the troposphere and humans' use of land can be considered layers of

4428-467: Is the study of soils, encompassing the sub-disciplines of pedology , which focuses on soil formation, and edaphology , which focuses on the relationship between soil and life. The earliest material found in the Solar System is dated to 4.5672 ± 0.0006  bya (billion years ago); therefore, the Earth itself must have been formed by accretion around this time. The formation and evolution of

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4536-465: Is thicker than oceanic crust , and it is far more varied in terms of composition. About 31% of this continental crust is submerged in shallow water, forming continental shelves. Land provides many ecosystem services , such as mitigating climate change, regulating water supply through drainage basins and river systems, and supporting food production. Land resources are finite, which has led to regulations intended to safeguard these ecosystem services, and

4644-429: Is unknown but is estimated to be at least 2 million. Finland has 168,000 lakes of 500 square metres (5,400 sq ft) in area, or larger, of which 57,000 are large (10,000 square metres (110,000 sq ft) or larger). Most lakes have at least one natural outflow in the form of a river or stream , which maintain a lake's average level by allowing the drainage of excess water. Some lakes do not have

4752-533: The 2019 Finnish parliamentary election in Central Finland: [REDACTED] Media related to Central Finland at Wikimedia Commons [REDACTED] Central Finland travel guide from Wikivoyage Lake A lake is an often naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land . Lakes lie completely on land and are separate from

4860-689: The Earth's magnetic field was established, which helped prevent the atmosphere from being stripped away by the solar wind . The atmosphere and oceans of the Earth continuously shape the land by eroding and transporting solids on the surface. Earth's crust formed when the molten outer layer of the planet Earth cooled to form a solid mass as the accumulated water vapour began to act in the atmosphere. Once land became capable of supporting life, biodiversity evolved over hundreds of millions of years, expanding continually except when punctuated by mass extinctions. The two models that explain land mass propose either

4968-759: The Malheur River . Among all lake types, volcanic crater lakes most closely approximate a circular shape. Glacial lakes are lakes created by the direct action of glaciers and continental ice sheets. A wide variety of glacial processes create enclosed basins. As a result, there are a wide variety of different types of glacial lakes and it is often difficult to define clear-cut distinctions between different types of glacial lakes and lakes influenced by other activities. The general types of glacial lakes that have been recognized are lakes in direct contact with ice, glacially carved rock basins and depressions, morainic and outwash lakes, and glacial drift basins. Glacial lakes are

5076-484: The Proto-Indo-European root * leǵ- ('to leak, drain'). Cognates include Dutch laak ('lake, pond, ditch'), Middle Low German lāke ('water pooled in a riverbed, puddle') as in: de:Wolfslake , de:Butterlake , German Lache ('pool, puddle'), and Icelandic lækur ('slow flowing stream'). Also related are the English words leak and leach . There is considerable uncertainty about defining

5184-523: The biosphere . Human manipulation of the land, including agriculture and architecture , can also be considered part of land. Land is formed from the continental crust , the layer of rock on which soil . groundwater , and human and animal activity sits. Though modern terrestrial plants and animals evolved from aquatic creatures, Earth's first cellular life likely originated on land. Survival on land relies on fresh water from rivers, streams, lakes, and glaciers, which constitute only three percent of

5292-486: The crust . Land plays an important role in Earth's climate system , being involved in the carbon cycle , nitrogen cycle , and water cycle . One-third of land is covered in trees, another third is used for agriculture , and one-tenth is covered in permanent snow and glaciers . The remainder consists of desert , savannah , and prairie . Land terrain varies greatly, consisting of mountains, deserts, plains, plateaus, glaciers, and other landforms . In physical geology,

5400-399: The density of water varies with temperature, with a maximum at +4 degrees Celsius, thermal stratification is an important physical characteristic of a lake that controls the fauna and flora , sedimentation, chemistry, and other aspects of individual lakes. First, the colder, denser water typically forms a layer near the bottom, which is called the hypolimnion . Second, normally overlying

5508-515: The motherland , fatherland , or homeland of its people. Many countries and other places have names incorporating the suffix -land (e.g. England , Greenland , and New Zealand ). The equivalent suffix -stan from Indo-Iranian , ultimately derived from the Proto-Indo-Iranian * sthāna- , is also present in many country and location names, such as Pakistan , Afghanistan , and others throughout Central Asia . The suffix

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5616-605: The ocean , although they may be connected with the ocean by rivers . Lakes, as with other bodies of water , are part of the water cycle , the processes by which water moves around the Earth. Most lakes are freshwater and account for almost all the world's surface freshwater, but some are salt lakes with salinities even higher than that of seawater . Lakes vary significantly in surface area and volume of water. Lakes are typically larger and deeper than ponds , which are also water-filled basins on land, although there are no official definitions or scientific criteria distinguishing

5724-434: The upwelling of magma and extrusion of lava, or erosion of mountains caused from water, glaciers, or aeolian processes, can create plateaus. Plateaus are classified according to their surrounding environment as intermontane , piedmont , or continental . A few plateaus may have a small flat top while others are wider. Buttes are smaller, with less extrusive and more intrusive igneous rock, while plateaus or highlands are

5832-654: The whale , that evolved from terrestrial mammals back to an aquatic lifestyle. Many megafauna of the past, such as non-avian dinosaurs , have become extinct due to extinction events, e.g. the Quaternary extinction event . Land is "deeply intertwined with human development." It is a crucial resource for human survival, humans depend on land for subsistence, and can develop strong symbolic attachments to it. Access to land can determine "survival and wealth," particularly in developing countries, giving rise to complex power relationships in production and consumption. Most of

5940-597: The Earth by extraterrestrial objects (either meteorites or asteroids ). Examples of meteorite lakes are Lonar Lake in India, Lake El'gygytgyn in northeast Siberia, and the Pingualuit crater lake in Quebec, Canada. As in the cases of El'gygytgyn and Pingualuit, meteorite lakes can contain unique and scientifically valuable sedimentary deposits associated with long records of paleoclimatic changes. In addition to

6048-432: The Earth's crust. About 30 percent of land has a dry climate, due to losing more water through evaporation than it gains from precipitation . Since warm air rises, this generates winds, though Earth's rotation and uneven sun distribution also play a part. Land is commonly defined as the solid, dry surface of Earth. It can also refer to the collective natural resources that the land holds, including rivers , lakes , and

6156-571: The Lusatian Lake District, Germany. In India, Sudarshana Lake is a historical artificial lake located in the semi-arid region of Girnar, Gujarat, originally constructed during the reign of Chandragupta Maurya. See: List of notable artificial lakes in the United States Meteorite lakes, also known as crater lakes (not to be confused with volcanic crater lakes ), are created by catastrophic impacts with

6264-628: The Solar System bodies occurred in tandem with the Sun. In theory, a solar nebula partitions a volume out of a molecular cloud by gravitational collapse, which begins to spin and flatten into a circumstellar disc , out of which the planets then grow (in tandem with the star). A nebula contains gas, ice grains and dust (including primordial nuclides ). In nebular theory , planetesimals begin to form as particulate matter accumulates by cohesive clumping and then by gravity. The primordial Earth's assembly took 10– 20  myr . By 4.54 ± 0.04 bya ,

6372-866: The base of the valley has remained in place for more than 100 years but the terrain below the lake is in danger of a catastrophic flood if the dam were to fail during a future earthquake. Tal-y-llyn Lake in north Wales is a landslide lake dating back to the last glaciation in Wales some 20000 years ago. Aeolian lakes are produced by wind action . These lakes are found mainly in arid environments, although some aeolian lakes are relict landforms indicative of arid paleoclimates . Aeolian lakes consist of lake basins dammed by wind-blown sand; interdunal lakes that lie between well-oriented sand dunes ; and deflation basins formed by wind action under previously arid paleoenvironments. Moses Lake in Washington , United States,

6480-506: The climate change impacts on habitats and biodiversity, as well as natural resources, in the target areas. Land cover change detection and mapping is a key component of interdisciplinary land change science , which uses it to determine the consequences of land change on climate. Land change modeling is used to predict and analyze changes in land cover and use. Soil is a mixture of organic matter , minerals , gases , liquids , and organisms that together support life . Soil consists of

6588-636: The coast is important for major parts of the global food and economic system, and they provide many ecosystem services to humankind. For example, important human activities happen in port cities . Coastal fisheries for commercial, recreational, and subsistence purposes, and aquaculture are major economic activities and provide jobs, livelihoods, and protein for the majority of coastal human populations. Other coastal spaces like beaches and seaside resorts generate economic activity through tourism . Marine coastal ecosystems can also provide protection against sea level rise and tsunamis . In many countries,

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6696-419: The coastal mangrove is the primary source of wood for fuel (e.g. charcoal) and building materials. Coastal ecosystems have a much higher capacity for carbon sequestration than many terrestrial ecosystems , and as such can play a critical role in the near future to help mitigate climate change effects by uptake of atmospheric anthropogenic carbon dioxide . A subcontinental area of land surrounded by water

6804-915: The courses of mature rivers, where a river channel has widened over a basin formed by eroded floodplains and wetlands . Some lakes are found in caverns underground . Some parts of the world have many lakes formed by the chaotic drainage patterns left over from the last ice age . All lakes are temporary over long periods of time , as they will slowly fill in with sediments or spill out of the basin containing them. Artificially controlled lakes are known as reservoirs , and are usually constructed for industrial or agricultural use, for hydroelectric power generation, for supplying domestic drinking water , for ecological or recreational purposes, or for other human activities. The word lake comes from Middle English lake ('lake, pond, waterway'), from Old English lacu ('pond, pool, stream'), from Proto-Germanic * lakō ('pond, ditch, slow moving stream'), from

6912-518: The creation of lakes by the disruption of preexisting drainage networks, it also creates within arid regions endorheic basins that contain salt lakes (also called saline lakes). They form where there is no natural outlet, a high evaporation rate and the drainage surface of the water table has a higher-than-normal salt content. Examples of these salt lakes include Great Salt Lake and the Dead Sea . Another type of tectonic lake caused by faulting

7020-622: The difference between lakes and ponds , and neither term has an internationally accepted definition across scientific disciplines or political boundaries. For example, limnologists have defined lakes as water bodies that are simply a larger version of a pond, which can have wave action on the shoreline or where wind-induced turbulence plays a major role in mixing the water column. None of these definitions completely excludes ponds and all are difficult to measure. For this reason, simple size-based definitions are increasingly used to separate ponds and lakes. Definitions for lake range in minimum sizes for

7128-580: The direction of the steepest slope. Hypsometric tints are colors placed between contour lines to indicate elevation relative to sea level . A difference between uplands, or highlands , and lowlands is drawn in several earth science fields. In river ecology, " upland " rivers are fast-moving and colder than "lowland" rivers, encouraging different species of fish and other aquatic wildlife to live in these habitats. For example, nutrients are more present in slow-moving lowland rivers, encouraging different species of macrophytes to grow there. The term "upland"

7236-981: The earliest known supercontinents, Rodinia , began to break apart. The continents later recombined to form Pannotia , 600– 540 mya , then finally Pangaea , which also broke apart 180 mya . A continuous area of land surrounded by an ocean is called a landmass. Although it is most often written as one word to distinguish it from the usage "land mass"—the measure of land area—it may also be written as two words. There are four major continuous landmasses on Earth: Afro-Eurasia , America (landmass) , Antarctica , and Australia (landmass) , which are subdivided into continents. Up to seven geographical regions are commonly regarded as continents. Ordered from greatest to least land area, these continents are Asia , Africa , North America , South America , Antarctica , Europe , and Australia . Terrain refers to an area of land and its features. Terrain affects travel, mapmaking, ecosystems, and surface water flow and distribution. Over

7344-536: The exception of criterion 3, the others have been accepted or elaborated upon by other hydrology publications. The majority of lakes on Earth are freshwater , and most lie in the Northern Hemisphere at higher latitudes . Canada , with a deranged drainage system , has an estimated 31,752 lakes larger than 3 square kilometres (1.2 sq mi) in surface area. The total number of lakes in Canada

7452-490: The geological continents and the areas of shallow seabed close to their shores, known as continental shelves . This layer is sometimes called sial because its bulk composition is richer in aluminium silicate and has a lower density compared to the oceanic crust , called sima which is richer in magnesium silicate . Changes in seismic wave velocities have shown that at a certain depth (the Conrad discontinuity ), there

7560-409: The growth of coral reefs , and meteorite impacts are among the processes that constantly reshape Earth's surface over geological time . Erosion transports one part of land to another via natural processes, such as wind , water, ice , and gravity . In contrast, weathering wears away rock and other solid land without transporting the land somewhere else. Natural erosional processes usually take

7668-402: The harvest of crops. Floodplains provided agricultural land for some of the earliest civilizations . Erosion is often a main driver for the creation of plains and valleys, with rift valleys being a noticeable exception. Fjords are glacial valleys that can be thousands of meters deep, opening out to the sea. Any natural void in the ground which can be entered by a human can be considered

7776-422: The hypolimnion is a transition zone known as the metalimnion . Finally, overlying the metalimnion is a surface layer of warmer water with a lower density, called the epilimnion . This typical stratification sequence can vary widely, depending on the specific lake or the time of year, or a combination of both. The classification of lakes by thermal stratification presupposes lakes with sufficient depth to form

7884-623: The igneous rocks granite and andesite . Less common is basalt , a denser volcanic rock that is the primary constituent of the ocean floors . Sedimentary rock is formed from the accumulation of sediment that becomes buried and compacted together . Nearly 75% of the continental surfaces are covered by sedimentary rocks, although they form about 5% of the crust. The most abundant silicate minerals on Earth's surface include quartz , feldspars , amphibole , mica , pyroxene and olivine . Common carbonate minerals include calcite (found in limestone ) and dolomite . The rock that makes up land

7992-907: The intentional damming of rivers and streams, rerouting of water to inundate a previously dry basin , or the deliberate filling of abandoned excavation pits by either precipitation runoff , ground water , or a combination of both. Artificial lakes may be used as storage reservoirs that provide drinking water for nearby settlements , to generate hydroelectricity , for flood management , for supplying agriculture or aquaculture , or to provide an aquatic sanctuary for parks and nature reserves . The Upper Silesian region of southern Poland contains an anthropogenic lake district consisting of more than 4,000 water bodies created by human activity. The diverse origins of these lakes include: reservoirs retained by dams, flooded mines, water bodies formed in subsidence basins and hollows, levee ponds, and residual water bodies following river regulation. Same for

8100-471: The karst regions at the Dalmatian coast of Croatia and within large parts of Florida . A landslide lake is created by the blockage of a river valley by either mudflows , rockslides , or screes . Such lakes are most common in mountainous regions. Although landslide lakes may be large and quite deep, they are typically short-lived. An example of a landslide lake is Quake Lake , which formed as

8208-411: The lake level. Dry land Land , also known as dry land , ground , or earth , is the solid terrestrial surface of Earth not submerged by the ocean or another body of water . It makes up 29.2% of Earth's surface and includes all continents and islands . Earth's land surface is almost entirely covered by regolith , a layer of rock , soil , and minerals that forms the outer part of

8316-476: The land is divided into two major categories: Mountain ranges and relatively flat interiors called cratons . Both form over millions of years through plate tectonics . Streams – a major part of Earth's water cycle – shape the landscape , carve rocks, transport sediments, and replenish groundwater. At high elevations or latitudes , snow is compacted and recrystallized over hundreds or thousands of years to form glaciers, which can be so heavy that they warp

8424-489: The land will influence how much solar radiation reaches its surface. High latitudes receive less solar radiation than low latitudes. The land's topography is important in creating and transforming airflow and precipitation . Large landforms, such as mountain ranges, can divert wind energy and make air parcels less dense and therefore able to hold less heat. As air rises, this cooling effect causes condensation and precipitation. Different types of land cover will influence

8532-425: The land's albedo , a measure of the solar radiation that is reflected, rather than absorbed and transferred to Earth. Vegetation has a relatively low albedo, meaning that vegetated surfaces are good absorbers of the sun's energy. Forests have an albedo of 10–15 percent while grasslands have an albedo of 15–20 percent. In comparison, sandy deserts have an albedo of 25–40 percent. Land use by humans also plays

8640-705: The land. Land cover refers to the material physically present on the land surface, for example, woody crops, herbaceous crops, barren land, and shrub-covered areas. Artificial surfaces (including cities) account for about a third of a percent of all land. Land use refers to human allocation of land for various purposes, including farming, ranching, and recreation (e.g. national parks); worldwide, there are an estimated 16.7 million km (6.4 million sq mi) of cropland, and 33.5 million km (12.9 million sq mi) of pastureland. Land cover change detection using remote sensing and geospatial data provides baseline information for assessing

8748-657: The largest lakes on Earth are rift lakes occupying rift valleys, e.g. Central African Rift lakes and Lake Baikal . Other well-known tectonic lakes, Caspian Sea , the Sea of Aral , and other lakes from the Pontocaspian occupy basins that have been separated from the sea by the tectonic uplift of the sea floor above the ocean level. Often, the tectonic action of crustal extension has created an alternating series of parallel grabens and horsts that form elongate basins alternating with mountain ranges. Not only does this promote

8856-528: The layers of sediment at the bottom of a meromictic lake remain relatively undisturbed, which allows for the development of lacustrine deposits . In a holomictic lake, the uniformity of temperature and density allows the lake waters to completely mix. Based upon thermal stratification and frequency of turnover, holomictic lakes are divided into amictic lakes , cold monomictic lakes , dimictic lakes , warm monomictic lakes, polymictic lakes , and oligomictic lakes. Lake stratification does not always result from

8964-560: The level of a lake are controlled by the difference between the input and output compared to the total volume of the lake. Significant input sources are precipitation onto the lake, runoff carried by streams and channels from the lake's catchment area, groundwater channels and aquifers, and artificial sources from outside the catchment area. Output sources are evaporation from the lake, surface and groundwater flows, and any extraction of lake water by humans. As climate conditions and human water requirements vary, these will create fluctuations in

9072-410: The low point of −418 m (−1,371 ft) at the Dead Sea , to a maximum altitude of 8,848 m (29,029 ft) at the top of Mount Everest. The mean height of land above sea level is about 797 m (2,615 ft), with 98.9% of dry land situated above sea level. Relief refers to the difference in elevation within a landscape; for example, flat terrain would have "low relief", while terrain with

9180-481: The mainland; lakes cut off from larger lakes by a bar; or lakes divided by the meeting of two spits. Organic lakes are lakes created by the actions of plants and animals. On the whole they are relatively rare in occurrence and quite small in size. In addition, they typically have ephemeral features relative to the other types of lakes. The basins in which organic lakes occur are associated with beaver dams, coral lakes, or dams formed by vegetation. Peat lakes are

9288-424: The mode of origin, lakes have been named and classified according to various other important factors such as thermal stratification , oxygen saturation, seasonal variations in lake volume and water level, salinity of the water mass, relative seasonal permanence, degree of outflow, and so on. The names used by the lay public and in the scientific community for different types of lakes are often informally derived from

9396-485: The moon Titan , which orbits the planet Saturn . The shape of lakes on Titan is very similar to those on Earth. Lakes were formerly present on the surface of Mars, but are now dry lake beds . In 1957, G. Evelyn Hutchinson published a monograph titled A Treatise on Limnology , which is regarded as a landmark discussion and classification of all major lake types, their origin, morphometric characteristics, and distribution. Hutchinson presented in his publication

9504-415: The morphology of the lakes' physical characteristics or other factors. Also, different cultures and regions of the world have their own popular nomenclature. One important method of lake classification is on the basis of thermal stratification, which has a major influence on the animal and plant life inhabiting a lake, and the fate and distribution of dissolved and suspended material in the lake. For example,

9612-406: The most numerous lakes in the world. Most lakes in northern Europe and North America have been either influenced or created by the latest, but not last, glaciation, to have covered the region. Glacial lakes include proglacial lakes , subglacial lakes , finger lakes , and epishelf lakes. Epishelf lakes are highly stratified lakes in which a layer of freshwater, derived from ice and snow melt,

9720-791: The names include: Lakes may be informally classified and named according to the general chemistry of their water mass. Using this classification method, the lake types include: A paleolake (also palaeolake ) is a lake that existed in the past when hydrological conditions were different. Quaternary paleolakes can often be identified on the basis of relict lacustrine landforms, such as relict lake plains and coastal landforms that form recognizable relict shorelines called paleoshorelines . Paleolakes can also be recognized by characteristic sedimentary deposits that accumulated in them and any fossils that might be contained in these sediments. The paleoshorelines and sedimentary deposits of paleolakes provide evidence for prehistoric hydrological changes during

9828-441: The ocean surface and leaves a ring of reefs around it. Mountains are features that usually rise at least 300 metres (980 ft) higher than the surrounding terrain. The formation of mountain belts is called orogenesis, and results from plate tectonics . For example, where a plate at a convergent plate boundary pushes one plate above the other, mountains could be formed by either collisional events, such that Earth's crust

9936-562: The organic-rich deposits of pre-Quaternary paleolakes are important either for the thick deposits of oil shale and shale gas contained in them, or as source rocks of petroleum and natural gas . Although of significantly less economic importance, strata deposited along the shore of paleolakes sometimes contain coal seams . Lakes have numerous features in addition to lake type, such as drainage basin (also known as catchment area), inflow and outflow, nutrient content, dissolved oxygen , pollutants , pH , and sedimentation . Changes in

10044-405: The past 150 years. Plate tectonics refers to the theory that Earth's lithosphere is divided into "tectonic plates" that move over the mantle. This results in continental drift , with continents moving relative to each other. The scientist Alfred Wegener first hypothesized the theory of continental drift in 1912. More researchers gradually developed his idea throughout the 20th century into

10152-408: The planet warms, it has been predicted that soils will add carbon dioxide to the atmosphere due to increased biological activity at higher temperatures, a positive feedback (amplification). This prediction has, however, been questioned on consideration of more recent knowledge on soil carbon turnover. Continental crust is the layer of igneous , sedimentary , and metamorphic rocks that forms

10260-433: The plant. Through photosynthesis , most plants nourish themselves from sunlight and water, breathing in carbon dioxide and breathing out oxygen. Between 20 and 50% of oxygen is produced by land vegetation. Unlike plants, terrestrial animals are not a monophyletic group —that is, a group including all terrestrial animals does not encompass all lineages from a common ancestor . This is because there are organisms, such as

10368-441: The primordial Earth had formed. Earth's atmosphere and oceans were formed by volcanic activity and outgassing that included water vapour . The origin of the world's oceans was condensation augmented by water and ice delivered by asteroids , protoplanets , and comets . In this model , atmospheric " greenhouse gases " kept the oceans from freezing while the newly formed Sun was only at 70% luminosity . By 3.5 bya ,

10476-405: The smallest municipality in the whole Mainland Finland in terms of population, is also located in the region. The idea of a province of Central Finland was born at the end of the 19th century. The concept was developed by the district doctor Wolmar Schildt , whose article for Suometar first appeared in 1856. In the late 19th and early 20th centuries, the provincial identity of Central Finland

10584-404: The thermal stratification, as well as the degree and frequency of mixing, has a strong control over the distribution of oxygen within the lake. Professor F.-A. Forel , also referred to as the "Father of limnology", was the first scientist to classify lakes according to their thermal stratification. His system of classification was later modified and improved upon by Hutchinson and Löffler. As

10692-456: The times that they existed. There are two types of paleolake: Paleolakes are of scientific and economic importance. For example, Quaternary paleolakes in semidesert basins are important for two reasons: they played an extremely significant, if transient, role in shaping the floors and piedmonts of many basins; and their sediments contain enormous quantities of geologic and paleontologic information concerning past environments. In addition,

10800-641: The two. Lakes are also distinct from lagoons , which are generally shallow tidal pools dammed by sandbars or other material at coastal regions of oceans or large lakes. Most lakes are fed by springs , and both fed and drained by creeks and rivers , but some lakes are endorheic without any outflow, while volcanic lakes are filled directly by precipitation runoffs and do not have any inflow streams. Natural lakes are generally found in mountainous areas (i.e. alpine lakes ), dormant volcanic craters , rift zones and areas with ongoing glaciation . Other lakes are found in depressed landforms or along

10908-446: The water on Earth. The vast majority of human activity throughout history has occurred in habitable land areas supporting agriculture and various natural resources . In recent decades, scientists and policymakers have emphasized the need to manage land and its biosphere more sustainably, through measures such as restoring degraded soil , preserving biodiversity , protecting endangered species , and addressing climate change . Land

11016-701: The widely accepted theory of plate tectonics of today. Several key characteristics define modern understanding of plate tectonics. The place where two tectonic plates meet is called a plate boundary , with different geological phenomena occurring across different kinds of boundaries. For example, at divergent plate boundaries , seafloor spreading is usually seen, in contrast with the subduction zones of convergent or transform plate boundaries . Earthquakes and volcanic activity are common in all types of boundaries. Volcanic activity refers to any rupture in Earth's surface where magma escapes, therefore becoming lava . The Ring of Fire , containing two-thirds of

11124-512: The widest, and mesas are a general-sized plateau with horizontal bedrock strata . Wide, flat areas of land are called plains , which cover more than one-third of Earth's land area. When they occur as lowered areas between mountains, they can create valleys , canyons or gorges, and ravines . A plateau can be thought of as an elevated plain. Plains are known to have fertile soils and be important for agriculture due to their flatness supporting grasses suitable for livestock and facilitating

11232-467: The word pond , and a lesser number of names ending with lake are, in quasi-technical fact, ponds. One textbook illustrates this point with the following: "In Newfoundland, for example, almost every lake is called a pond, whereas in Wisconsin, almost every pond is called a lake." One hydrology book proposes to define the term "lake" as a body of water with the following five characteristics: With

11340-466: The world's volcanos, and over 70% of Earth's seismological activity , comprises plate boundaries surrounding the Pacific Ocean . Earth's land interacts with and influences its climate heavily, since the land's surface heats up and cools down faster than air or water. Latitude , elevation , topography , reflectivity , and land use all have varying effects on climate. The latitude of

11448-570: Was joined with Kuorevesi and part of Längelmäki , which previously belonged to Pirkanmaa . Kuhmoinen was also part of Central Finland until 2021, when it joined the region of Pirkanmaa. For history, geography and culture see: Tavastia , Savonia , Ostrobothnia The region of Central Finland consists of 22 municipalities , six of which have city status (marked in bold). Joutsa sub-region : Jyväskylä sub-region : Jämsä sub-region : Keuruu sub-region : Saarijärvi-Viitasaari sub-region : Äänekoski sub-region : Results of

11556-617: Was originally a shallow natural lake and an example of a lake basin dammed by wind-blown sand. China's Badain Jaran Desert is a unique landscape of megadunes and elongated interdunal aeolian lakes, particularly concentrated in the southeastern margin of the desert. Shoreline lakes are generally lakes created by blockage of estuaries or by the uneven accretion of beach ridges by longshore and other currents. They include maritime coastal lakes, ordinarily in drowned estuaries; lakes enclosed by two tombolos or spits connecting an island to

11664-400: Was strengthened by associations, organisations and companies that expanded into the provinces. The Central Finland Province was established in 1960, but was abolished in the county reform of 1997 . A province is a common administrative unit based on the autonomous decision-making power of municipalities and embodies local democracy at the regional level vis-à-vis the state, while a county is

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