The terminal lakes of the Murray River, Australia, were predominantly fresh before large-scale upstream water abstraction: Evidence from sedimentary diatoms and hydrodynamical modelling

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dc.contributor.authorTibby, J.
dc.contributor.authorHaynes, D.
dc.contributor.authorGibbs, M.
dc.contributor.authorMosley, L.
dc.contributor.authorBourman, R.P.
dc.contributor.authorFluin, J.
dc.date.issued2022
dc.description.abstractThe Murray River is Australia's longest river, draining the continent's largest exoreic catchment. The river is Australia's most economically valuable, but is highly degraded by water extraction. The Murray River's terminal lakes, Lakes Alexandrina and Albert, formed following the mid-Holocene marine transgression. These lakes are part of one of the most ecologically important wetland ecosystems on the Australian continent and are recognised as internationally significant by the Ramsar Convention. As a result of upstream water extraction, the Lower Lakes are threatened by rising salinity. To combat this threat, water is allocated to maintain the Lower Lakes as freshwater ecosystems. This practice is part of the Murray-Darling Basin Plan, one of the largest environmental water allocation plans in the world. The water allocations and the natural history of the Lower Lakes are the subject of academic and public debate, since the water would otherwise be used for consumptive purposes, particularly irrigated agriculture, upstream. Recent modelling postulated that the lakes were saline for much of the period between 8500 and 5000 years ago. However, using new sedimentary diatom and hydrodynamic modelling evidence, we demonstrate that the Lower Lakes were fresh for most of this time, particularly after 7200 years ago. Elevated Murray River discharge between 7200 and 6600 years ago prevented sea water ingress, despite sea levels +1 m higher than present. After 6600 years ago, the lakes remained predominately fresh. Current management is, therefore, consistent with the lakes' history before European colonisation.
dc.description.statementofresponsibilityJ. Tibby, D. Haynes, M., L. Mosley, R.P. Bourman, J. Fluin
dc.identifier.citationScience of the Total Environment, 2022; 835:1-8
dc.identifier.doi10.1016/j.scitotenv.2022.155225
dc.identifier.issn0048-9697
dc.identifier.issn1879-1026
dc.identifier.orcidTibby, J. [0000-0002-5897-2932]
dc.identifier.orcidGibbs, M. [0000-0001-6653-8688]
dc.identifier.orcidMosley, L. [0000-0002-7446-8955]
dc.identifier.orcidBourman, R.P. [0000-0003-3384-8254]
dc.identifier.urihttps://hdl.handle.net/2440/136366
dc.language.isoen
dc.publisherElsevier
dc.relation.granthttp://purl.org/au-research/grants/arc/LP100100215
dc.relation.granthttp://purl.org/au-research/grants/arc/DP190102782
dc.rights© 2022 Published by Elsevier B.V.
dc.source.urihttps://doi.org/10.1016/j.scitotenv.2022.155225
dc.subjectDiatom
dc.subjectEnvironmental water
dc.subjectEnvironmental flows
dc.subjectHolocene
dc.subjectWater management
dc.subjectMurray-Darling basin
dc.subject.meshDiatoms
dc.subject.meshWater
dc.subject.meshEcosystem
dc.subject.meshRivers
dc.subject.meshAustralia
dc.subject.meshLakes
dc.titleThe terminal lakes of the Murray River, Australia, were predominantly fresh before large-scale upstream water abstraction: Evidence from sedimentary diatoms and hydrodynamical modelling
dc.typeJournal article
pubs.publication-statusPublished

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