Nursing lakes back to health aim of international student’s study.
Research enabling an international PhD student to take a snapshot of 10,000 years of New Zealand’s geological past may hold answers to some of today’s most pressing environmental issues.
Julian Eschenroeder, came to New Zealand from his home in Germany in 2021 to complete a thesis towards a doctorate in geology. He is hoping his ‘journey’ back in time will give clues to how we can improve the health of many of Aotearoa’s 3800 lakes.
Based at the University of Otago, he is analysing sediment and water samples from three lakes in Southland to see how changes in climate over thousands of years impact lake health. One of the lakes he hopes will produce data spanning 10,000 years.
His work is being lauded by Education New Zealand Manapou ki te Ao (ENZ) as an example of the benefits international students can bring to New Zealand.
“Many of these students bring unique skills and make valuable contributions,” ENZ Chief Executive Grant McPherson says. “They help connect New Zealand thinking with the world and now that our borders are open, New Zealanders can gradually expect to see more bright minds, like Julian, from the international community coming here.”
Eschenroeder says all three lakes he is studying are pristine and relatively untouched by human activity. “We want to understand how their ecosystems have reacted to changes in climate over thousands of years and, hopefully, apply this information to modern times.”
His research comes on the heels of the biggest survey of lake health in New Zealand, the Lakes380 Research Programme, which found 45 per cent of natural lakes are in poor health or worse. The project has been conducting research on 10 per cent of Aotearoa’s lakes since 2017.
Eschenroeder, whose findings will ultimately be embedded into the Lakes380 data, says water quality is important to New Zealand and will be more so in the future: “But, because it is so young, I believe the country has a rare opportunity to return to a relatively pristine environment.”
Eschenroeder, who came to New Zealand after graduating with a Master’s degree in geology from the University of Heidleberg in south-west Germany, will spend the next three years completing his thesis.
He is extracting sediment from three lakes - Lake Bright, Lake Laffy and Lake Richter - and hopes the samples from Lake Bright will give him data spanning 4000 years. At Lake Laffy he is hoping to mine information as far back as 10,000 years.
“We are looking into the past to see the future; it is important to learn from the past,” he says. “By doing that we can start to understand how climate has varied and changed over time and what impact it has had on lakes. This will help us extrapolate into the future, so we are better prepared to protect and recover New Zealand’s great lakes.”
New Zealand has over 3800 lakes but data exists for fewer than 5 per cent of them - and most of what exists goes back only 20 to 30 years.
Eschenroeder says lake health is impacted by a variety of natural and human causes including changes in the atmospheric circulation, the plant cover of the surrounding catchment and increasing temperatures due to the release of large amounts of carbon dioxide and other greenhouse gases into the atmosphere.
The data he is collecting will help researchers understand what changes in lake health are the result of natural ebbs-and-flows and what is caused by human activities.
Samples to a depth of about two metres are taken from the lakes to produce profiles of elemental compositions and organic biomarkers stacked full of information: “I can see how its surroundings have affected the lake over time; what it has meant for its water quality, vegetation and productivity. It’s a bit like looking at tree rings.”
Eschenroeder says it is too early yet to say what results will come from his research.
Does he expect his work will have any impact on the future health of New Zealand’s lakes? “I hope so. It will be important because there are not many sites in New Zealand where lake health has been analysed or understood, but it will depend on what the people who come after me will do with the data.”
Eschenroeder says he decided to come to New Zealand after he saw the research position advertised: “It was the other side of the world, but New Zealand is a nice country, especially nature-wise. It was also a bonus to be able to work outdoors.”
While he says he is unsure whether he will remain in New Zealand once he has completed his PhD, “right now I’m happy to be here.”
For more information on New Zealand’s international education sector visit: https://newlook.enz.govt.nz/