Developing methods that use Australian chironomid (non-biting midge) larvae as proxies for past climate change

Chang, Jie, Shulmeister, James and Woodward, Craig (2013). Developing methods that use Australian chironomid (non-biting midge) larvae as proxies for past climate change. In: AOGS 2013: Asia-Oceania Geoscience Society 10th Annual Meeting, South Bank, QLD, Australia, (). 24-28 June, 2013.

Author Chang, Jie
Shulmeister, James
Woodward, Craig
Title of paper Developing methods that use Australian chironomid (non-biting midge) larvae as proxies for past climate change
Conference name AOGS 2013: Asia-Oceania Geoscience Society 10th Annual Meeting
Conference location South Bank, QLD, Australia
Conference dates 24-28 June, 2013
Publication Year 2013
Sub-type Published abstract
Open Access Status
Language eng
Formatted Abstract/Summary
Two methods that will use the fossilized remains of non-biting midge larvae (chironomids) preserved in lake sediments to reconstruct past changes in the Australian climate system during and after the last glacial maximum (LGM), are under development. Lake sediment samples were collected from the Australian temperate climate zone of Southeast Queensland, New South Wales, Victoria and Tasmania. Based on midge assemblages and 23 environmental variables sampled from 10 lakes in NSW (lakes sampled in 2012 field season), a preliminary Canonical correspondence analysis (CCA) revealed four variables that account for a signi´Čücant (P<0.1) portion of the explainable variance. These were, in order of explanatory power, Mean February Temperature (MeanFeb), Total Phosphorous, Chlorophyll-a and Mg2+. This preliminary result suggesting a model (transfer-function) to reconstruct past summer temperatures (MeanFeb) based on the temperature tolerance of Australian chironomid species living in southern Australian lakes today can be created.

The second method will be based on the stable oxygen isotope composition (δ18O) of the heads from southern Australian chironomids. Previous studies (Wooller et al., 2004; Verbruggen et al., 2011) have shown that the fossilized heads of non-biting midge larvae act as a ‘time capsule’ that preserves the δ18O of the lake water in which they live. A temperature effect will be one of the most important controls on lake water δ18O in southern Australia. Therefore δ18O from fossilized chironomid heads will be able to be used as another method for reconstructing past changes in temperature. Both of these methods will be applied to chironomid remains extracted from lake sediment deposits in southern Australia that span the LGM.

This study will be the first to develop a chironomid stable isotope method for reconstructing past temperature in the Southern Hemisphere, and the first worldwide to use both a chironomid transfer function and stable isotope methods on chironomids to reconstruct past temperature from the same sites.
Q-Index Code EX
Q-Index Status Provisional Code
Institutional Status UQ
Additional Notes Presented during the Session "BG07: Late Quaternary Environments of Temperate Australasia and Relationships with the Tropical Indo-pacific Region" as BG07-D5-PM1-P6-005(BG07-A001).

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Created: Wed, 05 Mar 2014, 14:22:55 EST by Helen Smith on behalf of School of Geography, Planning & Env Management