Researcher and Mens Shed build wave maker to understand microplastics trapped in coastal marine ecosystems
A wave-maker built with the help of some keen woodwork and mechanical enthusiasts is helping a marine ecology researcher understand how microplastics (plastics smaller than five millimetres) are affecting seagrass, mangrove and coral reef ecosystems in the waters of the Southern Great Barrier Reef.
Jack Greenshields, a marine ecologist and PhD researcher at CQUniversity’s Coastal Marine Ecosystems Research Centre in Gladstone, said the machine built by members of the Men’s Shed in Gladstone under his guidance is helping him to understand how and why microplastics are becoming trapped in different environments.
“I’m looking at how different flora and sediment types found in different ecosystems affect how microplastics become trapped” Mr Greenshields explained.
“For example, mangrove and seagrass sediment can be very silty, while beach sand is usually coarser ... my hypothesis is that the siltier sand found in mangroves and seagrasses are more likely to trap plastics than in heavy, denser beach sand, because they are more fluid and more likely to move around.
“I’m also looking at how that trapping affects the health of the mangroves and seagrasses as well.”
Transcript
My name is Jack Green Shields um I'm looking into microplastics in seagrasses mangroves and coral reefs yeah it looks kind of weird doesn't it um so machine is a is a wave machine it generates waves and what I'm looking at is how different sediment types in different ecosystems affects how microplastics get trapped in them so for example Mangrove sediment is very silty and coral sand and beach sand is more coarse and I'm looking out how waves and the impacts affects how the plastics get trapped my hypothesis is that the siltier sand in mangroves and seagrass are more likely to trap plastics than in heavier denser beach sand um because they're more fluid and they're more likely to move around so the plastics are more like to get trapped in the different layers of the sediment um and then I'll be looking at how that trapping affects the the health of the mangroves and the seagrass as well um I'm originally from near London in England um and I came over Australia cuz it's cuz I do marine ecology and Australia is probably the best place in the world to do Marine ecology I mean we're right next to the great barrier reef um there's so many like fantastic animals and yeah I can't believe I'm here most of the time cuz everybody's aware that plastic pollution is a thing but I want to draw attention to why people should really care about it you know there's there's plastics in the river plastics in the ocean okay it's a bit not nice to look at but the the more we understand about plastic the more we understand how much of a detrimental effect has an effect on on the animals and also like the flora as well um and that's why part of my project is is looking at whether the plastics getting trapped in these different ecosystems whether it has like a consequences on the health of the seagrass naturally seagrass um traps particular matter it traps the sediment it's really good at holding down sediment and it's really good for like juvenile fish and turtles and dugongs that eat it but because it's so good at trapping um this kind of particular matter and sediment um it also might be really good at trapping plastics it could take me anywhere in the world um there's loads of places I haven't been and loads of places I want to see but I can't deny that Australia is a beautiful country so many different climates and ecosystems in just in one country you've got everything you know you've got um you know from like mountains and jungles and and the reef as well is like one of the best in the world so there is a big part of me that does want to stay here.
He said seagrasses are naturally good at trapping particulate matter and holding down sediment, as well as providing a vital food source for juvenile fish, dugongs and turtles.
“Because it’s so good at trapping particulate matter and sediment, it may also be very good at trapping plastic, making them at risk of being hotspots for plastic pollution.”
However, this unique skillset of seagrass may also be troublesome for the animals that rely on them for habitats and food.
Mr Greenshields said while its common knowledge there are plastics in our waterways, he hopes to shed some light on why plastic is more than just a public eyesore, and why it’s important to take notice, sooner than later.
“I want to draw attention to why people should care about it. The more we understand about plastics, the more we understand how much of a detrimental effect it is having on the flora and fauna.”
The English-born researcher is part-way through his PhD project and believes he’s scored the best environmental backdrop to conduct his studies.
“Australia is one of the best places in the world to study marine ecology. We are right next to the Great Barrier Reef where there are so many fantastic animals ... I can’t believe I’m here most of the time.”
