Identification

Title

Reduction of the temperature sensitivity of minerotrophic fen methane emissions by simulated glacial atmospheric carbon dioxide starvation

Abstract

Variations to the global wetland CH₄ source strength in response to changes in orbital insolation patterns and atmospheric CO₂ concentration ([CO₂]a) are hypothesized to play an important role in determining glacial-interglacial variations in atmospheric CH₄ concentration ([CH₄]a). Here the interactive effects of temperature, a major controlling variable determining wetland CH₄ flux, and the low [CO₂]a of glacial intervals are investigated for the first time. We measured the temperature dependence of CH₄ emissions from replicated mesocosms (n = 8 per CO₂ treatment) collected from a minerotrophic fen and an ombrotrophic bog incubated in either ambient (c. 400 ppm) or glacial (c. 200 ppm) [CO₂]a located in the United Kingdom. CH₄ fluxes were measured at 5°C, 10°C, 15°C, 20°C, and 25°C and then in reverse order over a 20 day period under each [CO₂]a treatment. Results showed that the Q10 temperature response of CH₄ emissions from the Carex/Juncus-dominated fen declined significantly by approximately 39% under glacial [CO₂]a (ambient [CO₂]a = 2.60, glacial [CO₂]a = 1.60; P < 0.01). By contrast, the response of CH₄ emissions from the Sphagnum-dominated bog remained unaltered (ambient [CO₂]a = 3.67, glacial [CO₂]a = 3.67; P > 0.05). This contrasting response may be linked to differences in plant species assemblage and the varying impact of CO₂ starvation on plant productivity and carbon availability in the rhizosphere. Furthermore, our results provide empirical evidence to support recent model-based indications that glacial-interglacial variations in [CH₄]a may be explained by changes in wetland CH₄ source strength in response to orbitally forced changes in climate and [CO₂]a.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d73j3dtf

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

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South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2013-06-01T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact