Climate variability in south-eastern Australia over the last 1500 years inferred from the high-resolution diatom records of two crater lakes

Barr, Cameron; Tibby, John; Gell, Peter; Tyler, Jonathan; Zawadzki, Atun; Jacobsen, Geraldine

doi:10.1016/j.quascirev.2014.05.001

Cited by 39 publications

(38 citation statements)

References 117 publications

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“…So the broad mechanisms that control the present meander wavelength and the production rate of cutoff meanders has been in place for 7000 years. Jones et al (1998) revealed that, through this period P/E ratios have varied from 1.2 to 0.7 and Barr et al (2014) have demonstrated the existence of multi-decadal droughts. Using instrumental data Warner (1987) revealed multi-decadal drought-dominated and flood-dominated regimes.…”

Section: Introductionmentioning

confidence: 96%

Muddied Waters: The Case for Mitigating Sediment and Nutrient Flux to Optimize Restoration Response in the Murray-Darling Basin, Australia

Gell

Reid

2016

Front. Ecol. Evol.

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The waters of the Murray Darling Basin, Australia, have endured multiple stressors for more than a century. Detectable salinization impacts are evident from 1880 CE and elevated fluxes of sediments and nutrients are now widespread. Most wetlands examined paleolimnologically have shown increased sedimentation rates or have lost aquatic plant communities due to the shading effect of increased turbidity, prompting the observation that the waterways of the Murray Darling Basin are among 10 Australian ecosystems most at risk from tipping points. This post-European heightened sediment flux threatens the potential ecological recovery from the application of scarce and expensive environmental water. Nutrients and fine sediments are implicated as drivers of regime shifts that advantage phytoplankton and inhibit the growth of productive macrophyte beds. However, with the river channels identified as likely sources of sediments and sediment-bound phosphorous, it remains possible that the documented ecological changes represent an ongoing response from continued doses from the River. Syntheses of multiple paleolimnological records provide evidence for the management focus to be on sediment supply to maximize the ecological benefit from environmental flow allocations. Here we use paleolimnology to examine in detail the nature and magnitude of the response in a subset of 17 wetlands, to propose means of optimizing the ecological bounce from the release of river waters, encumbered with high doses of sediments and nutrients, to wetlands and floodplains.

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Section: Introductionmentioning

confidence: 96%

Muddied Waters: The Case for Mitigating Sediment and Nutrient Flux to Optimize Restoration Response in the Murray-Darling Basin, Australia

Gell

Reid

2016

Front. Ecol. Evol.

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“…Although some (pollen-based) rainfall reconstructions exist (Kershaw & Nix, 1988;Kershaw et al, 2004a,b), the majority of Australian hydrological reconstructions consist of nonquantitative lake water balance and speleothem oxygen isotope records (e.g. Denniston et al, 2013;Gouramanis et al, 2013;Barr et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Carbon isotope discrimination in leaves of the broad‐leaved paperbark tree, Melaleuca quinquenervia, as a tool for quantifying past tropical and subtropical rainfall

Tibby

Barr

McInerney

et al. 2016

Global Change Biology

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Quantitative reconstructions of terrestrial climate are highly sought after but rare, particularly in Australia. Carbon isotope discrimination in plant leaves (Δ leaf ) is an established indicator of past hydroclimate because the fractionation of carbon isotopes during photosynthesis is strongly influenced by water stress. Leaves of the evergreen tree Melaleuca quinquenervia have been recovered from the sediments of some perched lakes on North Stradbroke and Fraser Islands, south-east Queensland, eastern Australia. Here, we examine the potential for using M. quinquenervia ∆ leaf as a tracer of past rainfall by analysing carbon isotope ratios ( 13 C) of modern leaves. We firstly assess Δ leaf variation at the leaf and stand scale and find no systematic pattern within leaves or between leaves due to their position on the tree. We then examine the relationships between climate and Δ leaf for an 11 year timeseries of leaves collected in a litter tray. M. quinquenervia retains its leaves for 1-4 years; thus cumulative average climate data are used. There is a significant relationship between annual mean ∆ leaf and mean annual rainfall of the hydrological year for 1-4 years (i.e. 365-1460 days)prior to leaf fall (r 2 =0. 64, p=0.003, n=11). This relationship is marginally improved by accounting for the effect of pCO 2 on discrimination (r 2 =0.67, p=0.002, n=11). The correlation between rainfall and Δ leaf , and the natural distribution of Melaleuca quinquenervia around wetlands of eastern Australia, Papua New Guinea and New Caledonia offers significant potential to infer past rainfall on a wide range of spatial and temporal scales.3

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“…A number of studies have previously developed quantitative reconstructions of salinity within Australia, predominantly using spatial calibration models based on diatom and ostracod assemblages [9][10][11][12][13][14][15]. There are, however, a number of difficulties associated with some of these.…”

Section: Introductionmentioning

confidence: 99%

Mid-Infrared Spectroscopy as a Potential Tool for Reconstructing Lake Salinity

Cunningham

Tibby

Forrester

et al. 2016

Water

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Many aquatic ecosystems in Australia are impacted or threatened by salinisation; however, there is a paucity of records detailing the changes in salinity of individual water bodies that extend beyond a few decades. One way to overcome this issue is the use of inference models, which have typically been based on biological proxies. This pilot project investigates the potential for mid-infrared spectroscopy (MIRS) to provide an alternative method of reconstructing past salinity levels in Australian lakes. A small (19 lakes) calibration dataset was used to develop a MIRS-based lake water salinity inference model (measured vs. inferred salinity, based on leave-one-out cross-validation, R 2 = 0.64). This model and a previously published diatom-salinity model were both used to infer salinity levels in Tower Hill Lake in south-eastern Australia, over the last 60 years. Comparisons between these reconstructions and measured salinity data from Tower Hill Lake indicate that salinities inferred by the MIRS model more closely resembled the measured values than those produced using the diatom model, predominantly in terms of the actual values inferred, but also with regard to the trends observed. This supports the hypothesis that MIRS can provide a valuable new tool for reconstructing lake salinity.

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Climate variability in south-eastern Australia over the last 1500 years inferred from the high-resolution diatom records of two crater lakes

Cited by 39 publications

References 117 publications

Muddied Waters: The Case for Mitigating Sediment and Nutrient Flux to Optimize Restoration Response in the Murray-Darling Basin, Australia

Muddied Waters: The Case for Mitigating Sediment and Nutrient Flux to Optimize Restoration Response in the Murray-Darling Basin, Australia

Carbon isotope discrimination in leaves of the broad‐leaved paperbark tree, Melaleuca quinquenervia, as a tool for quantifying past tropical and subtropical rainfall

Mid-Infrared Spectroscopy as a Potential Tool for Reconstructing Lake Salinity

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