Marty Leist, AMSA’s Partnerships and Engagement Coordinator, visited the Gladstone men’s shed and he heard about a project the men had been working on with Jack Greenshields, a PhD student in Marine biology at the Central Queensland University.
One of the questions in Jack’s PhD was do microplastics get trapped in in seagrasses and mangrove ecosystems more so than in other marine environments such a beaches – and what are the health effects associated from that. In order to answer this question, he needed a wave machine to be able to conduct research.
Jack had an idea for what he needed, but quickly realised he had no idea how to build it or how to find someone who could attempt such a thing. A colleague suggested that Jack have a chat with the local men’s shed. Lucky for Jack, Gladstone is an area that is highly populated by retired engineers and many of them frequent the Gladstone men’s shed so there is a wealth of information and knowledge there.
So Jack talked to Malcolm Leinster, a retired mechanical engineer in the power generation industry. Malcom said he has the ability to design complex things but when it comes to complex control systems, he brings Daryl Bond in to solve those things. Darryl’s career was in the electrical industry – he has his electrician’s ticket and along with additional qualifications in control system tertiary education and a degree in information technology.
Jack wasn’t sure exactly what he needed and what could be done, so he collaborated with Malcom and Darryl to work that out, and together they built an incredible wave machine.
The wave machine has six separate tanks that slope upwards to generate a wave, with a sort of pendulum mechanism with a wedge shape that goes and up down and creates the wave on to a well of sediment. Each has a different treatment with seagrasses, and mangroves and so on. Then there is a pump that spins to create a tidal cycle, and the water goes up and down within the tank to create different kinds of waves that splash down on the sediment with the microplastics in it.
Jack said “For the results to be statistically significant and not merely result of chance, it’s really importantly for our research to create replicates so that you have identical things over and over again, which is why there are 6 tanks doing the exact same thing.
So the water goes up and down and the plunger making the waves on the sediment and you can see the plastics moving around. And you can see a core here and at the end of the experiment I will be looking at the core and see where are the plastics, how deep down they go and where they get trapped. And there will be different kinds of sediment in the wells because seagrass sediment, mangrove sediment, beach sediment and all different sizes and weights.”
The project wasn’t a quick process – it took about 18 months to complete and a few iterations to get some of the parts to work as they needed. With a very limited budget, the men managed to find some materials that were low cost or free, such as the timber for the tanks was recycled and treat it to make it waterproof. There were quite a number of complexities and problems that had to be solved during the build such as the mechanisms not interfering with the sediment.
Jack was very fortunate to find these guys, and he says “it would have actually been impossible for him to produce the wave machine if I’d had to pay an engineering firm to make it, and I’m very grateful!”
And Malcom and Darryl are contributing to some very valuable research for our environment.
Jack is hoping to have the results around September this year and hopefully finish his PhD!