Name: Kelsie Long DSCN0194

Area of study: Archaeogeochemistry

Project: Fish otolith geochemistry environmental conditions and past human occupation at Lake Mungo, NSW.

What does that mean??

Short version: I am using the chemical composition of fish otoliths (earstones) to determine past environmental conditions at Lake Mungo.

Long version: Lake Mungo is  a world heritage site in NSW where human remains, dated to beyond 40,000 years old, were excavated in the 1960s and 70s. The site also contains large amounts of otoliths.

Otoliths are calcium carbonate structures that grow in the inner ear of most animals, in humans they are tiny pebbles that help us with balance and hearing but in fish, otoliths preserve a record of salinity and temperature that I am using in my research. They form annual rings, similar to tree rings, and as each layer forms, trace elements from the surrounding water are taken up and incorporated. Many of the these elements change with the environment.

By studying the life of the humble fish through its otoliths we can learn about past changes in the environment. When it got hotter or colder, more or less saline, or whether there was a huge flood! At Lake Mungo they provide a link between people eating fish on the lakeshore and changes in the environment. I am starting to build up a record of lake level and climate change stretching back the 40,000 years of human occupation!

But there’s a catch. Not every element is affected by the environment alone. Some are affected by the fish’s diet or metabolism. So it is my job to figure out which elements are best suited to recording temperature and salinity. I have been firing lasers at modern versions of these otoliths taken from across Australia. Once I’ve untangled the various effects on the elements then I can apply my work to ancient otoliths at Lake Mungo.

How did I get here?

I don’t really know how I got here. I started an undergraduate Arts degree at ANU focusing on Archaeology and Bioanthropology (studying bones), with a smattering of French language classes, and somehow ended up doing a PhD at the Research School of Earth Sciences. It’s been a kind of happy, busy blur.

Where will I go?

I would really like to go overseas after my PhD. I have never lived abroad and I would really like to spend a year or two somewhere different, hopefully still doing some form of research! I’m also itching to go outside and do some digging, so maybe an archaeological dig overseas will be part of my future plans.