Reference : Ideas and perspectives: Carbon leaks from flooded land: do we need to replumb the inl...
Scientific journals : Article
Life sciences : Aquatic sciences & oceanology
http://hdl.handle.net/2268/232832
Ideas and perspectives: Carbon leaks from flooded land: do we need to replumb the inland water active pipe?
English
Abril, G. [> >]
Borges, Alberto mailto [Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Chemical Oceanography Unit (AGO) >]
12-Feb-2019
Biogeosciences
European Geosciences Union (EGU)
16
3
769-784
Yes (verified by ORBi)
International
17264170
17264189
Germany
[en] At the global scale, inland waters are a significant source of atmospheric carbon (C), particularly in the tropics. The active pipe concept predicts that C emissions from streams, lakes and rivers are largely fuelled by terrestrial ecosystems. The traditionally recognized C transfer mechanisms from terrestrial to aquatic systems are surface runoff and groundwater drainage. We present here a series of arguments that support the idea that land flooding is an additional significant process that fuels inland waters with C at the global scale. Whether the majority of CO2 emitted by rivers comes from floodable land (approximately 10% of the continents) or from well-drained land is a fundamental question that impacts our capacity to predict how these C fluxes might change in the future. Using classical concepts in ecology, we propose, as a necessary step forward, an update of the active pipe concept that differentiates floodable land from drained land. Contrarily to well-drained land, many wetlands (in particular riparian and littoral wetlands) combine strong hydrological connectivity with inland waters, high productivity assimilating CO2 from the atmosphere, direct transfer of litter and exudation products to water and waterlogged soils, a generally dominant allocation of ecosystem respiration (ER) below the water surface and a slow gas-exchange rate at the water–air interface. These properties force plants to pump atmospheric C to wetland waters and, when hydrology is favourable, to inland waters as organic C and dissolved CO2. This wetland CO2 pump may contribute disproportionately to CO2 emissions from inland waters, particularly in the tropics where 80% of the global CO2 emissions to the atmosphere atmosphere occur. In future studies, more care must be taken in the way that vertical and horizontal C fluxes are conceptualized along watersheds, and 2-D models that adequately account for the hydrological export of all C species are necessary. In flooded ecosystems, significant effort should be dedicated to quantifying the components of primary production and respiration by the submerged and emerged part of the ecosystem community and to using these metabolic rates in coupled hydrological–biogeochemical models. The construction of a global typology of wetlands that includes productivity, gas fluxes and hydrological connectivity with inland waters also appears necessary to adequately integrate continental C fluxes at the global scale.
Freshwater and OCeanic science Unit of reSearch - FOCUS
Researchers ; Professionals ; Students
http://hdl.handle.net/2268/232832
10.5194/bg-16-769-2019
https://www.biogeosciences.net/16/769/2019/
FP7 ; 240002 - AFRIVAL - African river basins: catchment-scale carbon fluxes and transformations.

File(s) associated to this reference

Fulltext file(s):

FileCommentaryVersionSizeAccess
Open access
bg-16-769-2019.pdfPublisher postprint1.3 MBView/Open

Bookmark and Share SFX Query

All documents in ORBi are protected by a user license.