Riparian plant material inputs to the Murray River, Australia: Composition, reactivity and role of nutrients

Graeme Esslemont, Bill Maher, Phillip Ford, Ian Lawrence

    Research output: Contribution to journalArticle

    14 Citations (Scopus)

    Abstract

    By changing riparian plants from Eucalypts to pasture and exotic deciduous trees, modern development has altered the type of carbon assimilated by Australian rivers. To investigate influences of plant litter substrates on biochemical oxygen demand, plant materials entering the Murray River were analyzed for their composition and mineralization potential. Plant materials were distinguished compositionally by two principal components, structural carbon and macronutrients, as: (i) Eucalyptus leaves, (ii) Eucalyptus bark and Casuarina cunninghamiana seed cone, (iii) grasses, (iv) macrophytes, (v) aquatic herbs, (vi) non-eucalypt leaf (Salix, Casuarina, Acacia). Ratios of C/P (1879-14524) and C/N (65-267) were relatively high in Eucalyptus bark, while mean N/P (7-60) ratios were similar among plant materials. Terrestrial weathering increased C/P and C/N ratios, while N/P ratios remained similar, due to greater loss of N and P relative to C. Aerobic decay experiments showed that nutrient supplementation accelerated decay of all organic substrates, except for grasses that decayed efficiently without supplementation. Aquatic herbs also had substantial carbon availability, macrophytes and non-eucalypt leaves had intermediate carbon availability, while eucalypt leaf and bark had intermediate to low carbon availabilities. Because biochemical oxygen demand varies with organic substrates sampled from the Murray River, and also with soluble nutrient availability, it is plausible that that modern changes to riverine plant communities and land use have influenced the biogeochemistry of this river toward faster, and more complete, processing of allochthonous carbon.

    Original languageEnglish
    Pages (from-to)963-974
    Number of pages12
    JournalJournal of Environmental Quality
    Volume36
    Issue number4
    DOIs
    Publication statusPublished - 2007

    Fingerprint

    Nutrients
    Rivers
    Carbon
    nutrient
    carbon
    Chemical analysis
    river
    Availability
    bark
    Biochemical oxygen demand
    biochemical oxygen demand
    substrate
    herb
    Substrates
    Biogeochemistry
    grass
    structural component
    deciduous tree
    biogeochemistry
    Weathering

    Cite this

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    title = "Riparian plant material inputs to the Murray River, Australia: Composition, reactivity and role of nutrients",
    abstract = "By changing riparian plants from Eucalypts to pasture and exotic deciduous trees, modern development has altered the type of carbon assimilated by Australian rivers. To investigate influences of plant litter substrates on biochemical oxygen demand, plant materials entering the Murray River were analyzed for their composition and mineralization potential. Plant materials were distinguished compositionally by two principal components, structural carbon and macronutrients, as: (i) Eucalyptus leaves, (ii) Eucalyptus bark and Casuarina cunninghamiana seed cone, (iii) grasses, (iv) macrophytes, (v) aquatic herbs, (vi) non-eucalypt leaf (Salix, Casuarina, Acacia). Ratios of C/P (1879-14524) and C/N (65-267) were relatively high in Eucalyptus bark, while mean N/P (7-60) ratios were similar among plant materials. Terrestrial weathering increased C/P and C/N ratios, while N/P ratios remained similar, due to greater loss of N and P relative to C. Aerobic decay experiments showed that nutrient supplementation accelerated decay of all organic substrates, except for grasses that decayed efficiently without supplementation. Aquatic herbs also had substantial carbon availability, macrophytes and non-eucalypt leaves had intermediate carbon availability, while eucalypt leaf and bark had intermediate to low carbon availabilities. Because biochemical oxygen demand varies with organic substrates sampled from the Murray River, and also with soluble nutrient availability, it is plausible that that modern changes to riverine plant communities and land use have influenced the biogeochemistry of this river toward faster, and more complete, processing of allochthonous carbon.",
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    Riparian plant material inputs to the Murray River, Australia: Composition, reactivity and role of nutrients. / Esslemont, Graeme; Maher, Bill; Ford, Phillip; Lawrence, Ian.

    In: Journal of Environmental Quality, Vol. 36, No. 4, 2007, p. 963-974.

    Research output: Contribution to journalArticle

    TY - JOUR

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    AU - Ford, Phillip

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