Hydrological change in southern Australia over 1750 years: a bivalve oxygen isotope record from the Coorong Lagoon
<p>Multi-centennial records of past hydroclimate change are essential for understanding the resilience of ecosystems to climatic events in addition to guiding conservation and restoration efforts. Such data are also crucial for examining the long-term controls over regional hydroclimate and th...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-07-01
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| Series: | Climate of the Past |
| Online Access: | https://cp.copernicus.org/articles/19/1383/2023/cp-19-1383-2023.pdf |
| Summary: | <p>Multi-centennial records of past hydroclimate change are essential
for understanding the resilience of ecosystems to climatic events in
addition to guiding conservation and restoration efforts. Such data are also
crucial for examining the long-term controls over regional hydroclimate and
the inherent variability in extreme droughts and floods. Here, we present a
1750-year record of hydroclimate variability in the Coorong South Lagoon,
South Australia, part of an internationally significant wetland system at
the mouth of Australia's largest river, the Murray River. Oxygen isotope
ratios were measured from <i>Arthritica</i> <i>helmsi</i> bivalve shells preserved in sediments. The
oxygen isotope record shows periods of persistent low and high moisture
balance, from <span class="inline-formula">∼500</span> to 1050 years and from <span class="inline-formula">∼1300</span> to 1800 years,
respectively, which is consistent with other hydroclimate reconstructions
from the region. The range of oxygen isotope values in the sedimentary
shells does not differ significantly from the estimated range of modern
specimens from the present-day lagoon. These data suggest that the
restricted and highly evaporated modern-day conditions are not markedly
different to the pre-impacted state over the last 1750 years, although the
absence of <i>A. helmsi</i> in the contemporary lagoon is likely a response to increased
salinity, nutrient loading, and anoxia during the last century. These
insights are potentially useful both in guiding management efforts to
conserve and restore the Coorong Lagoon and for understanding long-term water resource availability in the region.</p> |
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| ISSN: | 1814-9324 1814-9332 |