From ice age insects to the tropics: an introduction to new postdoctoral Stefan Engels

Stefan Engels in the field 
Hello, my name is Stefan Engels and I’ve just started a 3-year postdoctoral research project within the Centre for Environmental Geochemistry, between the School of Geography (University of Nottingham) and the BGS. I am a Dutch guy who’s lived most of his life in Utrecht. The Netherlands. I completed my PhD research at the Free University of Amsterdam, where I studied subfossil chironomid remains (insect jaws!) found in lake sediment records that were dated to the last glacial period around 50,000 years ago. I used the fossil insects of lakes to reconstruct past ecosystem development and to quantitatively infer past summer temperatures. My results showed that summer temperatures were probably as high as today across large parts of Europe during the middle of the last glacial, which was quite a surprise!

After finishing my PhD I moved to Stockholm and then Canada where I continued work into chironomids until I returned to The Netherlands in 2010 where I took up a post at the University of Amsterdam. My job was to use a range of different indicators and techniques to further study Holocene lake level changes on lakes across Europe. I used a combination of ground-penetrating radar imagery, palynology, chironomid analysis and geochemical tools to reconstruct past changes in precipitation. While I found evidence for changes between 3500 and 2500 years ago, I also noticed that my methods didn’t work so well in the sediments that covered the last few centuries. This turned out to be the result of overriding effects of lake ecosystem pollution, and using a different set of techniques (including sedimentary pigment analysis and coprostanol analysis) I was able to show that my study site had been polluted by man since the Medieval times.

Tasik Chini in Malaysia which is suffering due to
human impact
In my current project role within the Centre for Environmental Geochemistry I will be investigating human impact on SE Asia. Exponential population growth, urban expansion and climate change are affecting the quality of freshwaters across the globe, and especially so in Asia. The Tasik Chini wetland in Malaysia was known for its natural beauty and its dense lotus vegetation attracts lots of tourists to the area each year. However, construction of a weir, development of bauxite mines on the lake shore, and rubber and palm oil plantations all negatively affected the status of the natural ecosystem of the Tasik Chini wetland, and the lake currently suffers from invasive species and a decline in its lotus population and its fish fauna. In the current project I will investigate the effects of all the different drivers of ecosystem change in Tasik Chini, again incorporating a number of different indicator techniques.

Suzanne, Ginnie and Melanie with our Malaysian
collaborators on the shores of Tasik Chini 
I took up my role in January, so far I am spending my time becoming familiar with the previous work completed in the Tasik Chini area. I have also started to undertake my first batch of laboratory work, processing sediments from the Tasik Chini wetland by Dr Suzanne McGowan, Dr Ginnie Panizzo and Prof Melanie Leng last summer. Initial analyses are mainly focussed on establishing physical properties of the lake sediment core and to assess the potential of the material for further study. I am also gearing up to go into the field where I hope to be able to collect more sediment cores from the Tasik Chini wetland. I am really looking forward to this fieldtrip, and can’t help but comparing it to the first real fieldwork I ever did as an MSc student when I went to sample peat bogs in W Greenland – quite a different environment!

My main collaborators for this project are Dr Suzanne McGowan (University of Nottingham) and Dr Melanie Leng (BGS and University of Nottingham), but there are lots of other collaborators both at the university of Nottingham and the British Geological Survey as well as in Malaysia.

If you’d like to see more about Stefan’s previous research projects, take a look at the following links: - a professional mini-documentary on palaeoclimatology, aimed at undergrad students - an item broadcast by Dutch national television showing some of my work at Lake Uddelermeer (in Dutch)