Jake Martin was an MSc student at the University of Auckland School of Chemical Sciences, now a PhD candidate at Cambridge University in the UK. Jake has developed a simple spectrophotometer– a device which measures the transmittance or absorbance of light at specific wavelengths- made from lasercut plastic and a handful of electronic components. Jake has been kind enough to share his design with me because I have a background and ongoing professional interest in environmental monitoring. I am very impressed with the potential of this technology and am keen to promote it further to any public body or community interested in doing their own environmental monitoring.
Jake’s initial application was measuring nitrate concentration in water. This is a highly topical issue in New Zealand, where freshwater habitats have suffered significant degradation in recent years, often due to increasing nitrate inputsassociated with the expansion of dairy farming. The urine from thousands of cattle and the fertilisers used to stimulate pasture growth for them to graze on raises the concentration of nitrate and nitrite in streams, rivers, lakes, wetlands and groundwater. This causes nuisance algal and microbial growth, such as rock slime, phytoplankton and cyanobacteria blooms and periphyton growth. These compounds can also have sublethal and lethal effects upon animals if their concentrations rise high enough.
The ability for members of the public to go out and measure nitrogen concentrations in their own back yard is a huge step in connecting people and communities with their environments. It is also a valuable tool for farmers, many of whom are concerned about the consequences of nitrate emissions from their farms. In order to develop practices to minimise fluxes of nitrate into freshwater habitats, such as planting riparian margins, farmers need to be able to measure it cheaply and rapidly.
Jake’s design is wonderfully simple anyone can pick it up in about two minutes. I am going to be demonstrating it and handing out free kits at the Sea Week 2016 event at Cornwallis on Saturday 5th March. Anyone who is interested in the quality of freshwater and marine habitats in New Zealand should come down and check it out. On the day we also hope to be able to show people how to measure phosphate concentrations and water turbidity, two other major water quality parameters that can indicate just how clean and safe your environment is.
I will present my testing of the spectrophotometer and a detailed how-to in another post.