z-logo
Premium
Flooding Alters Plant‐Mediated Carbon Cycling Independently of Elevated Atmospheric CO 2 Concentrations
Author(s) -
Jones Scott F.,
Stagg Camille L.,
Krauss Ken W.,
Hester Mark W.
Publication year - 2018
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1029/2017jg004369
Subject(s) - cycling , environmental science , ecosystem , salt marsh , mesocosm , carbon cycle , soil carbon , flooding (psychology) , soil respiration , wetland , biogeochemical cycle , marsh , ecology , hydrology (agriculture) , environmental chemistry , soil water , chemistry , soil science , biology , geology , forestry , geography , psychology , psychotherapist , geotechnical engineering
Plant‐mediated processes determine carbon (C) cycling and storage in many ecosystems; how plant‐associated processes may be altered by climate‐induced changes in environmental drivers is therefore an essential question for understanding global C cycling. In this study, we hypothesize that environmental alterations associated with near‐term climate change can exert strong control on plant‐associated ecosystem C cycling and that investigations along an extended hydrologic gradient may give mechanistic insight into C cycling. We utilize a mesocosm approach to investigate the response of plant, soil, and gaseous C cycling to changing hydrologic regimes and elevated atmospheric carbon dioxide (CO 2 ) concentrations expected by 2100 in a coastal salt marsh in Louisiana, USA. Although elevated CO 2 had no significant effects on C cycling, we demonstrate that greater average flooding depth stimulated C exchange, with higher rates of labile C decomposition, plant CO 2 assimilation, and soil C respiration. Greater average flooding depth also significantly decreased the soil C pool and marginally increased the aboveground biomass C pool, leading to net losses in total C stocks. Further, flooding depths along an extended hydrologic gradient garnered insight into decomposition mechanisms that was not apparent from other data. In C‐4 dominated salt marshes, sea level rise will likely overwhelm effects of elevated CO 2 with climate change. Deeper flooding associated with sea level rise may decrease long‐term soil C pools and quicken C exchange between soil and atmosphere, thereby threatening net C storage in salt marsh habitats. Manipulative studies will be indispensable for understanding biogeochemical cycling under future conditions.

This content is not available in your region!

Continue researching here.

Having issues? You can contact us here