Breadcrumbs

Addressing a major environmental challenge

18 June 2018

Thomas Corbett webb

Thomas Corbett, congratulated by Associate Minister for Primary Industries Meka Whaitiri.

A University of Waikato PhD student has been awarded a substantial scholarship from the Ministry for Primary Industries (MPI).

To help address a major environmental challenge – the impact changes to land and water use is having on the environment, Thomas Corbett is developing a nitrate/nitrite and phosphate sensor for freshwater that he hopes will be easy to use, accurate and affordable, to measure the impacts of run-off and leaching.

Thomas was one of eight doctoral students to receive an MPI scholarship, worth up to $50,000, presented by Associate Minister for Primary Industries Meka Whaitiri at this year’s Fieldays.

He says understanding the effects of run-off and leaching is fundamental to the sustainability of primary production, and requires accurate measurements. The sensor will be based on the Diffusive Gradients in Thin Films (DGT) technique.

A DGT device comprises a small plastic container with an exposure window to solution of known area. In the container there are three layers: the filter membrane (which is at the solution boundary), diffusion layer, and the binding layer. Ions from a solution diffuse through the membrane and diffusion layer to a binding layer where the nutrient of interest is rapidly and irreversibly bound.

The DGT devices can be deployed for days to weeks – providing time-weighted average concentration of the nutrient. Getting an average concentration rather than a one-off sampling will provide the landowner with much greater certainty of hotspots of nutrient losses and allow targeted mitigation strategies.

“I majored in chemistry for my first degree in Auckland [a conjoint BA/BSc with first class honours] and my current research will have a strong chemistry component to expand the DGT methodology,” Thomas says.

He will be working with Professor Louis Schipper, an environmental biogeochemist, environmental geochemist Dr Adam Hartland and inorganic chemist Professor Bill Henderson. His research will be a combination of lab-based development of the DGT methodology and in-field testing.

Thomas grew up in the Far North, on a small beef farm outside Kerikeri, and during his high school years he played competitive golf and with his younger sister ran the family farm.

“We ran the farm at a relatively low intensity, and considered many environmental consequences when making decisions. It was a very formative experience and it’s definitely influenced my desire to work in the primary sector.

“When I got back from travelling for three years I started to think about further study, perhaps a masters. Waikato’s Dr Julia Mullarney recommended I contact Louis after discussing my research interests with her. Louis said I should consider a PhD seeing as I’d already done honours. That came as a bit of a shock, but I thought about it and said yes.”

MPI scholarship applicants must meet strict criteria and the selection process was rigorous, Thomas says. “The first round required a brief research proposal related to MPIs scientific needs and my future in the primary sector, then after submitting a more in depth proposal, I had to go to Wellington to give a presentation to the selection board. So it was pretty cool to be selected.”

MPI appoint a senior mentor who, along with his supervisors, will also help guide Thomas through his PhD journey.