GlossaryGLOSSARY
Aerenchymous species
Plant species with a tissue consisting of thin-walled cells and large intercellular spaces that allow for plantinternal circulation of air, enhancing gas exchange between the root layer and the atmosphere. Aerenchymous
plants are widespread in wetlands.

Aquic
Condition pertaining to soil layers that are virtually free of dissolved oxygen and have a reducing environment
because of saturation with ground water or capillary water (adapted from Table 2.3, Chapter 2, Volume 4 of the2006 IPCC Guidelines).

Aquaculture
Organised production of aquatic animals and plants (e.g. fish, crustaceans, and seaweeds) in marine orfreshwater environments. The most important aquacultural practices in coastal wetlands are fish farming andshrimp ponds.

Autotrophic respiration
Release of carbon dioxide by living plants from internal metabolism (growth and maintenance).

Blanket bog
A bog type (see bog) that covers the underlying undulating landscape like a blanket.

Bog
Peatland only fed by precipitation and consequently generally nutrient-poor and acidic (see also fen).

Brackish/saline water
Water that generally contains 0.5 or more parts per thousand (ppt) of dissolved salts.

Brackish/saline wetland
A wetland inundated or saturated by brackish/saline water for all or part of the year.

CO 2 or CH 4 or N 2 O Flux
Rate of flow of dissolved or gaseous CO2 or CH4 or N2O across a given surface or area and over a certain
amount of time.

Chamber
Gas-tight enclosure used for measuring greenhouse gas fluxes.

Coastal wetland
Wetland at or near the coast that is influenced by brackish/saline water and/or astronomical tides.

Constructed wetland for wastewater treatment
Wetland designed and constructed to use natural processes to help treat wastewater.

Created wetland
Previously dry land converted to a wetland by raising the water table in inland wetlands or removing
obstructions to hydrologic flow and/or raising or lowering the soil elevation to appropriate tidal elevation incoastal wetlands.

Dam
A barrier constructed to obstruct the flow of water.

Denitrification
Reduction of nitrate or nitrite to molecular nitrogen.

Dissolved Inorganic Carbon (DIC)
Sum of all inorganic carbon species in solution (e.g. carbonate, bicarbonate, carbonic acid, carbon dioxide).

Dissolv ed Organic Carbon (DOC)
Organic carbon remaining in solution after filtering the sample, typically using a 0.45 micrometer filter.

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GlossaryDitch
A long, narrow excavation made in the ground by digging, as for draining or irrigating land.

Drainage/drained
Artificial lowering of the soil water table. In this supplement, ‘drainage’ is used to describe the act of changing a
wet soil into a dry soil. A drained soil is a soil that formerly has been a wet soil but as a result of humanintervention is tending to become a dry soil, to which the 2006 IPCC Guidelines would apply.

Drainage class
A collection of water table depths sharing a common characteristic. (e.g. the class ‘shallow-drained’ ischaracterized by having a mean annual water table depth of less than 30 cm below the surface, whereas the class‘deep-drained’ has a mean annual water table depth of 30 cm and deeper below the surface; Chapter 2, thissupplement). The mean annual water table is the water table averaged over a period of several years.

Eddy covariance
Micrometeorological method that uses differences in concentration associated with turbulence in the air toquantify net vertical gas exchange.

Eutrophic
Nutrient-rich (see also oligotrophic).

Extraction
In this supplement, to remove soil (and associated biomass, dead wood and litter).

Fen
Peatland that in addition to precipitation water, also receives water that has been in contact with mineral soil orbedrock (see also bog).

Fish cages or pens
Types of enclosures at the water surface or fixed to the seabed that maintain a free exchange of water and fineparticles and used to cultivate aquatic organisms for human consumption.

Fish pond
In this supplement, a general term covering ponds constructed in brackish or saline water, designed to retain andculture fish for commercial production (aquaculture).

Flooded LandIn this supplement, Flooded Land is defined as: water bodies where human activities have caused changes in theamount of surface area covered by water, typically through water level regulation. Examples of Flooded Land
include reservoirs for the production of hydroelectricity, irrigation, and navigation. Regulated lakes and rivers
that do not have substantial changes in water area in comparison with the pre-flooded ecosystem are notconsidered as Flooded Lands. Some rice paddies are cultivated through flooding of land, but because of theunique characteristics of rice cultivation, rice paddies are addressed in Chapter 5 (Cropland) of the Guidelines(Chapter 7.3, Volume 4 of the 2006 IPCC Guidelines).

Flooding
Overflowing of water on land normally dry.

Floodplain
Land adjacent to a stream or river that experiences flooding during periods of high discharge.

Freshwater
Water that contains < 0.5 parts per thousand (ppt) of various dissolved salts.

Freshwater wetland
A wetland inundated or saturated by freshwater for all or part of the year.

Heterotrophic respiration
The total of physical and chemical processes in an organism by which oxygen is conveyed to tissues and cells,
and the oxidation products CO2 and water, are given off.

Horizontal subsurface flow ( HSSF)
A type of constructed wetland with horizontal subsurface flow.

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GlossaryHydroperiod
Inundation frequency, differentiated into permanent and intermittent.

Immobilization
With respect to nitrogen, the process by which inorganic N, as ammonium (NH4) and nitrate (NO3) is assimilated
by microorganisms.

Impoundment
Body of water formed by containment.

Inundated/inundation
Covered by water; see also Flooded Land.

Mangrove
A coastal wetland that has trees able to live in areas that are tidally flooded by brackish/saline water.

MarshA wetland, typically treeless, periodically inundated and characterized by grasses, sedges, cattails, and rushes.

Methanogen
Microorganism that produces methane during the decomposition of organic matter.

Methanotroph
Microorganism that utilizes methane for metabolism.

Mineral soil
Every soil that does not meet the definition of organic soil (see Annex 3A.5, Chapter 3, Volume 4 of the 2006
IPCC Guidelines).

Mineralization
The process of converting organic compounds to inorganic compounds.

Minerotrophic(Of peatland): supplied with nutrients from other sources (groundwater, flood water) than the atmosphere (seealso ombrotrophic).

Nitrification
The microbial oxidation of NHx to NO3.

Ombrotrophic
Only supplied with nutrients by the atmosphere (see also minerotrophic) and consequently often acidic and lowin nutrients.

Oligotrophic
Poor to extremely poor in nutrients (see also eutrophic).

Organic soil
In line with the 2006 IPCC Guidelines (Annex 3A.5, Chapter 3, Volume 4), soil that satisfies the requirements 1and 2, or 1 and 3 below:
1) Thickness of organic horizon greater than or equal to 10 cm. A horizon of less than 20 cm must have 12
percent or more organic carbon when mixed to a depth of 20 cm;
2) Soils that are never saturated with water for more than a few days must contain more than 20 percent
organic carbon by weight (i.e. about 35 percent organic matter); and3) Soils are subject to water saturation episodes and have either:a)

At least 12 percent organic carbon by weight (i.e. about 20 percent organic matter) if the soil has noclay; orb) At least 18 percent organic carbon by weight (i.e. about 30 percent organic matter) if the soil has 60%
or more clay; orc)

An intermediate proportional amount of organic carbon for intermediate amounts of clay.

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Glossary

Except for the 10 cm criterion mentioned under 1), the 2006 IPCC Guidelines do not define a minimum
thickness for the organic horizon to allow for country-specific definitions of organic soil.

Paludiculture
Agriculture and forestry on wet (undrained, rewetted) organic soil.

Particulate Organic Carbon (POC)
Organic carbon that is larger than 0.45 micrometer in size (see also Dissolved Organic Carbon).

Peat 1
Soft, porous or compressed, sedentary deposit of which a substantial portion is partly decomposed plant material
with high water content in the natural state (up to about 90 percent). Countries may define peat according to theirnational circumstances.

Peat compaction
Volume reduction of peat in the aerated zone above the water table, resulting in increased bulk density.

Peat consolidation
Volume reduction of peat in the saturated zone below the water table owing to increased loading (downwardpressure) from the drained top peat (by loss of buoyancy) on the peat below. See also peat compaction.

Peat decomposition
The process by which peat is broken down into simpler forms of matter. In mineralisation, decomposition
proceeds to the mineral components, including CO2 and H2O.

Peat subsidence
The loss in peat elevation resulting from peat compaction, peat comsolidation and peat oxidation.

Prairie
An extensive area of flat or rolling, predominantly treeless grassland; often considered to be part of thetemperate grasslands, savannas, and shrublands biome.

Refractory carbon
Soil carbon that does not get broken down and released as dissolved or gaseous CO2 (predominantly bymicroorganisms) within the time scale of the inventory.

Rehabilitation
The re-establishment, on formerly drained sites, of some but not necessarily all the hydrological, biogeochemicaland ecological processes and functions that characterized pre-drainage conditions.

Restoration
The process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed. In case ofdrained former wetlands, restoration always has to include ‘rewetting’.

Rewetted soil
A soil that formerly has been drained but as a result of human intervention has once more become a wet soil.

Rewetting
The deliberate action of changing a drained soil into a wet soil, e.g. by blocking drainage ditches, disablingpumping facilities or breaching obstructions.

RiparianOf, inhabiting, or situated on the bank of a river.

Saline inland wetland
Wetland that accumulates salts in its soil typically as a result of semi-arid to arid conditions.

Salt production
The production of salt by evaporating brackish or saline tidal water.

Seagrass meadow
1

Consistent with the definition of peat found in the Energy sector of the 2006 IPCC Guidelines (Volume 2, Chapter 1, Table1.1)

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Glossary

Coastal wetland vegetated by seagrass species (rooted, flowering plants), permanently or tidally covered bybrackish/saline water.

Sediment
Deposit of inorganic or organic material that has been carried and deposited by wind, water, or ice.

Semi-natural treatment wetland
Natural wetland that has been modified for wastewater treatment, e.g. by increasing the volume reserved (i.e. bydams) and constructing channels for targeting the influent and effluent.

Surface flow ( SF)A type of constructed wetland with surface flow.

Swamp
Wetlands dominated by trees or woody species.

Tidal freshwater wetland
Wetland inundated or saturated for all or part of the year by tidal freshwater. The upper boundary is recognized
as the landward extent of tidal inundation.

Tidal marsh
Marsh inundated or saturated for all or part of the year by tidal freshwater or brackish/saline water. The upperboundary is recognized as the landward extent of tidal inundation.

Total organic carbon ( TOC)
All carbon in organic matter.

Vertical subsurface flow ( VSSF)
A type of constructed wetland with vertical subsurface flow.

Wastewater treatment plant
A facility designed to receive wastewater and to remove materials that damage water quality and threaten publichealth and safety when discharged into receiving streams or bodies of water.

Waterborne carbon
DIC, DOC or POC contained in or conveyed by water.

Wetland
In this supplement, the term ‘wetland’ is used to refer to land with a wet soil. For the IPCC land-use category
Wetlands, see below.

Wetlands
This guidance uses the term ‘Wetlands’ (with capital ‘W’ and plural) when referring to the IPCC land-use
category Wetlands. The terms ‘wetland’ or ‘wetlands’ (except in titles with lowercase ‘w’ and singular or plural)
are used to refer to land with wet soil (see above).

Wetland mineral soil
A mineral soil that is classified as an ‘aquic soil’ or a ‘gleysol’ according to the default mineral soil classificationin Annex 3A.5, Figures 3A.5.3 and 3A.5.4, Chapter 3, Volume 4 of the 2006 IPCC Guidelines.

Wet soil
A soil that is inundated or saturated by water for all or part of the year to the extent that biota, adapted toanaerobic conditions, particularly soil microbes and rooted plants, control the quality and quantity of the net
annual greenhouse gas emissions and removals.

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