Wetland

A wetland is a distinct <a href="/facts/Semi-aquatic/6JHes4oC">semi-aquatic</a> <a href="/facts/Ecosystem/kVE8mSmR">ecosystem</a> whose <a href="/facts/Groundcover/eeoJc7pa">groundcovers</a> are <a href="/facts/Flooded/FDQjJeXW">flooded</a> or <a href="/facts/Soil_saturation/N0MlAYmb">saturated</a> in <a href="/facts/Water/0lkXnJPK">water</a>, either permanently, for years or decades, or only seasonally. Flooding results in <a href="/facts/Oxygen/acyn6o8r">oxygen</a>-poor (<a href="/facts/Anoxic_waters/vLdveWX0">anoxic</a>) processes taking place, especially in the <a href="/facts/Soil/5Ddpr3QM">soils</a>. Wetlands form a transitional zone between <a href="/facts/Waterbodies/MoDAUuW4">waterbodies</a> and <a href="/facts/Dry_land/sYfevlh5">dry lands</a>, and are different from other <a href="/facts/Terrestrial_ecosystem/CsE4XjgP">terrestrial</a> or <a href="/facts/Aquatic_ecosystem/TkNqBg4N">aquatic ecosystems</a> due to their <a href="/facts/Vegetation/nAHr9kjk">vegetation</a>'s <a href="/facts/Root/Hk7ucczM">roots</a> having adapted to oxygen-poor <a href="/facts/Hydric_soil/dxaNEKrV">waterlogged soils</a>. They are considered among the most <a href="/facts/Biologically_diverse/GruakEzs">biologically diverse</a> of all ecosystems, serving as <a href="/facts/Habitat/zo1DN2gA">habitats</a> to a wide range of aquatic and semi-aquatic <a href="/facts/Plant/X5BMDMvS">plants</a> and <a href="/facts/Animal/4b8J33nd">animals</a>, with often improved <a href="/facts/Water_quality/PcEERmpX">water quality</a> due to plant removal of <a href="/facts/Nutrient_pollution/pUjJDmU7">excess nutrients</a> such as <a href="/facts/Nitrate/5AnVlYnL">nitrates</a> and <a href="/facts/Phosphorus/27xCeIqs">phosphorus</a>.
Wetlands exist on every <a href="/facts/Continent/Pysd9Sw8">continent</a>, except <a href="/facts/Antarctica/bEM5Lem5">Antarctica</a>. The water in wetlands is either <a href="/facts/Freshwater/xMP2TxwI">freshwater</a>, <a href="/facts/Brackish/f6z3UXCa">brackish</a> or <a href="/facts/Seawater/fRBJjbws">saltwater</a>. The main types of wetland are defined based on the dominant <a href="/facts/Plant/X5BMDMvS">plants</a> and the source of the water. For example, <a href="/facts/Marsh/AG0WLJ2K">marshes</a> are wetlands dominated by <a href="/facts/Aquatic_plant/Tr1rlK49">emergent</a> <a href="/facts/Herbaceous_vegetation/u6myDhE2">herbaceous vegetation</a> such as <a href="/facts/Reed_(plant)/yb90F7ND">reeds</a>, <a href="/facts/Cattail/069AClzk">cattails</a> and <a href="/facts/Sedge/A1oI2H0U">sedges</a>. <a href="/facts/Swamp/rjE9QKpm">Swamps</a> are dominated by <a href="/facts/Woody_vegetation/xXCI9yys">woody vegetation</a> such as <a href="/facts/Tree/3q0G4cbP">trees</a> and <a href="/facts/Shrub/X1gKVxL5">shrubs</a> (although <a href="/facts/Reedswamp/d5vJ8zpA">reed swamps</a> in Europe are dominated by reeds, not trees). <a href="/facts/Mangrove_forest/JreUUsuG">Mangrove forest</a> are wetlands with <a href="/facts/Mangrove/JreUUsuG">mangroves</a> and <a href="/facts/Halophytic/4XXvx3UX">halophytic</a> woody plants that have evolved to tolerate <a href="/facts/Salty_water/Fb4Fvm79">salty water</a>.
Examples of wetlands classified by the sources of water include <a href="/facts/Tidal_wetland/1SYLVN97">tidal wetlands</a>, where the water source is <a href="/facts/Ocean_tides/zNstvWPv">ocean tides</a>; <a href="/facts/Estuaries/WmkSInmK">estuaries</a>, water source is mixed tidal and river waters; <a href="/facts/Floodplain/EUKqIbj5">floodplains</a>, water source is excess water from overflowed rivers or lakes; and <a href="/facts/Bog/LuPbb2qV">bogs</a> and <a href="/facts/Vernal_pond/ztyFdarU">vernal ponds</a>, water source is <a href="/facts/Rainfall/MLqcQEyx">rainfall</a> or <a href="/facts/Meltwater/SYU7KHgg">meltwater</a>. The world's largest wetlands include the <a href="/facts/Amazon_River_basin/kVk5XeHA">Amazon River basin</a>, the <a href="/facts/West_Siberian_Plain/gIm96b8U">West Siberian Plain</a>, the <a href="/facts/Pantanal/MjTqwb7q">Pantanal</a> in South America, and the <a href="/facts/Sundarbans/QSmnsDwe">Sundarbans</a> in the <a href="/facts/Ganges/q0IGurvB">Ganges</a>-<a href="/facts/Brahmaputra/wx7sGl1a">Brahmaputra</a> delta. 
Wetlands contribute many <a href="/facts/Ecosystem_service/Fm4owYGV">ecosystem services</a> that benefit people. These include for example <a href="/facts/Water_purification/rguCGW3q">water purification</a>, stabilization of shorelines, storm protection and <a href="/facts/Flood_control/rf0476SJ">flood control</a>. In addition, wetlands also process and condense <a href="/facts/Carbon/ukrgQexo">carbon</a> (in processes called <a href="/facts/Carbon_fixation/JqvfmCdH">carbon fixation</a> and <a href="/facts/Carbon_sequestration/WDBvr9eU">sequestration</a>), and other nutrients and <a href="/facts/Water_pollution/SCUhUYqB">water pollutants</a>. Wetlands can act as a <a href="/facts/Carbon_sink/Gv7uXVmT">sink</a> or a <a href="/facts/Carbon_source/RGcJRgVG">source</a> of carbon, depending on the specific wetland. If they function as a carbon sink, they can help with <a href="/facts/Climate_change_mitigation/GgkoeWMk">climate change mitigation</a>. However, wetlands can also be a significant <a href="/facts/Greenhouse_gas_emissions_from_wetlands/IvP0ced8">source of methane emissions</a> due to <a href="/facts/Anaerobic_decomposition/EUaMIVpM">anaerobic decomposition</a> of soaked <a href="/facts/Detritus/8IjhrXA6">detritus</a>, and some are also emitters of <a href="/facts/Nitrous_oxide/Jvys91lI">nitrous oxide</a>. 
Humans are disturbing and damaging wetlands in many ways, including <a href="/facts/Oil_and_gas_extraction/GyyC7lTo">oil and gas extraction</a>, building infrastructure, <a href="/facts/Overgrazing/nkzowGh1">overgrazing</a> of <a href="/facts/Livestock/Quhv6GvP">livestock</a>, <a href="/facts/Overfishing/fAxN80Jo">overfishing</a>, alteration of wetlands including <a href="/facts/Dredging/81sUKhnF">dredging</a> and draining, <a href="/facts/Nutrient_pollution/pUjJDmU7">nutrient pollution</a>, and <a href="/facts/Water_pollution/SCUhUYqB">water pollution</a>. Wetlands are more threatened by <a href="/facts/Environmental_degradation/MTI24T7B">environmental degradation</a> than any other <a href="/facts/Ecosystem/kVE8mSmR">ecosystem</a> on Earth, according to the <a href="/facts/Millennium_Ecosystem_Assessment/n8tBzlMd">Millennium Ecosystem Assessment</a> from 2005. Methods exist for assessing wetland <a href="/facts/Ecological_health/htdFNySj">ecological health</a>. These methods have contributed to <a href="/facts/Wetland_conservation/KJcTP9Ul">wetland conservation</a> by raising public awareness of the functions that wetlands can provide. Since 1971, work under an international treaty seeks to identify and protect "<a href="/facts/Wetlands_of_international_importance/tz4RgjpA">wetlands of international importance</a>."

Wetland open-in-new

Wetland