Production and fate of dissolved organic matter in ecosystems with low human impact

Gauthier, Anthony (2009) Production and fate of dissolved organic matter in ecosystems with low human impact. PhD thesis, James Cook University.

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Abstract

Dissolved organic matter (DOM) is an essential parameter of quality and aquatic ecosystem functioning. The production of DOM in soils and its fate as it moves through the catchment were studied during experiments conducted at different scales, from the soil microcosm to the catchment, using natural abundance tracing of stable carbon isotopes (δ13C). At the catchment scale, we highlighted the role of wetlands in the formation of dissolved organic carbon (DOC). During discharge events we nevertheless observed the mobilisation of several sources of DOC to feed rivers. During laboratory experiments, we demonstrated that forest type influences the fate of water extractable organic carbon content in soil. The substitution of native forests by Douglas plantations reduces carbon inputs into the soil and mineralisation rates of soil organic carbon, which also depend on temperature. However, the water extractable organic carbon content of forest soils, which is influenced by the forest type, depends neither on carbon mineralisation rate nor temperature. We have therefore concluded that in the surface horizons of forest soils, the DOC mainly originates, not from the decomposition of soil organic matter but rather, from the vegetation via litter leachate.

Item ID: 11378
Item Type: Thesis (PhD)
Keywords: dissolved organic matter, dissolved organic carbon, extractable organic carbon, land use change, carbon absorption, native forests, carbon in soils, timber plantations, catchment vegetation, carbon leaching, forest soils
Additional Information:

This thesis was submitted as a conjoint thesis, with the Universite de Bourgogne, also titled: Production et devenir des matieres organiques: dissoutes dans les hydrosystemes faiblement anthropises.

The thesis is written in English and French. In English only: Chapters 1,2 and 4, and English reference sources only.

In French only: Acknowledgements, Table of contents, Lists of figures and tables; Chapter 3; Conclusion, French reference sources and Appendices.

Date Deposited: 26 May 2010 23:58
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0503 Soil Sciences > 050302 Land Capability and Soil Degradation @ 50%
05 ENVIRONMENTAL SCIENCES > 0503 Soil Sciences > 050304 Soil Chemistry (excl Carbon Sequestration Science) @ 50%
SEO Codes: 96 ENVIRONMENT > 9614 Soils > 961403 Forest and Woodlands Soils @ 50%
96 ENVIRONMENT > 9609 Land and Water Management > 960906 Forest and Woodlands Land Management @ 50%
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