Bianca Cavazzin

 

Research title

Palaeotemperature Change in the Drought-prone Prairie

Research summary

Research title

Paleotemperature change in drought-prone Canadian prairies

Summary of research

The interior of Canada is a drought-prone region that is reliant on grain and livestock production. The region is characterized by large changes in seasonal temperatures (~35.6C) and relatively low rainfall (36.4cm/yr). Little is known about the past temperatures in this region before the human instrumental measurements that go back about 100 years. However, sustained droughts, such as the Dust Bowl Drought during the 1930s that left crops destroyed and witnessed farming income losses >$300 million (USD) have occurred historically. Contrary to the typical summer dry season that occurs annually here, the driest part of the Dust Bowl Drought (1936 AD) experienced one of the coldest years on record. The global climate mechanism for this and other major droughts (i.e., 1978 and 1996 AD) are still not fully understood.

The aim of this project is to focus on the past 1500 years of geologic history to characterize known climatic events such as the Medieval Warm Period (~900-1200 AD), the Little Ice Age (~1500-1800 AD), and the Dust Bowl Drought (1930’s AD) and determine the links between these events and to global climate drivers.

In this project, I will develop and apply novel lake biomarker temperature proxies to this climatically-sensitive region, namely long-chain algal diols and bacterial membrane lipids called GDGTs (glycerol dialkyl glycerol tetraethers). I will investigate algal-derived, long-chain diols whose chain length and structure have been shown to correlate linearly with the growth temperature of the producing algae, (e.g. Rampen et al. 2012). I will also investigate GDGT proxies for temperature and pH. These proxies will be investigated from a suite of 109 surface sediments of lakes across the Canadian prairie that spans a 5° latitudinal gradient and spring surface water temperature gradient of about 9°C. Existing metadata is available for the comparison of developed biomarker indices with modern environmental data, including temperature, lake water pH, hydrogen and oxygen isotopes, and conductivity. These 109 samples will be used as a training set to develop the biomarker proxies for down-core use in this region.

 


Grants

  • NERC -IAPETUS Doctoral Training Partnership 2015-2019