Slaying algal blooms with the sun

The Australian Stockholm Junior Water Prize winner for 2023 is Mikayla Rodger, who talked about algal blooms and how she wants to stop them.

The Australian Stockholm Junior Water Prize winner for 2023 is a Year 10 student from Meriden School in New South Wales. Mikayla Rodger talked about her inspiration to tackle the problem of cyanobacteria and her future.

“I believe it is important for young women to become more involved in STEM, pursue their interests and strive to make real change in the world around them,” said Mikayla Rodger, the 2023 Australian Stockholm Junior Water Prize winner.

Cyanobacteria is a microscopic phytoplankton responsible for an irreversible decline in water quality. Many substances deal with cyanobacteria, also known as blue-green algae. Few deal with their root causes, which is where Rodger steps in.

A student at Meriden, Rodger won the prize due to her research investigating an eco-friendly and affordable system that could help prevent a cyanobacteria bloom. Her solar-powered machine, called SolarCyanoSlayer, can reduce cyanobacteria blooms by circulating, oxygenating, and filtering a body of water. The system, designed to be used by farming dams, is made from recycled materials and is suitable for both short- and long-term implementation.

“Mikayla started work on her machine in 2022,” said Meriden’s Head of Science, Tara Richards. “She worked with her classroom teacher to expand on her original idea. Her original project ran for about 12 months as part of an application for the CSIRO CREST Awards.”

Creativity in Research, Engineering, Science and Technology (CREST) is a national education program made available by CSIRO. It is designed for students in Years K to 12 to develop their science, technology, engineering, and mathematics (STEM) skills. Based on an inquiry approach to teaching and learning, students are engaged at all levels in science investigations and technology projects to progress from structured inquiry to open inquiry.

“Applying for the CREST Awards meant Mikayla had to make some adjustments to her original project and flesh out her proposal,” said Richards. “As part of the school’s annual Science Showcase, she got further feedback from the judges. That meant more fine-tuning before Mikayla came second in the Science Teachers Association of New South Wales (STANSW) Young Scientist Awards in the Innovations and Engineering Design, Grades 9-10. She actually finished second to one of our other students.”

How did she get involved in this research?

“For me, science is a vessel for discovery. I get to learn about how things work and apply it to the world around me. Science allows me to question, explore and uncover. It provides results that can help to develop solutions to some of the world’s greatest challenges,” said Rodger.

Rodger has always been a fan of the outdoors. She is involved with some of Meriden’s extracurricular environmental clubs and programs. Finding herself an award winner was something unexpected.

“My research on cyanobacteria was not something I saw as a global issue,” she said. “Rather, I did a small project that evolved into something much bigger. It started with just a tub of cyanobacteria, and then I designed a system to help prevent them from occurring.”

Inspiration for Rodger came from spending time bushwalking. While walking, she came across a waterway covered in what she described as “this layer of murky green.” On returning home, Rodger discovered that it was cyanobacteria, which was devastating the local ecosystem.

“I did some research on the impact of cyanobacteria around the world. The Murray River in Australia has been devastated by it, and the Selwyn River in Canterbury, New Zealand, has had similar ecological damage. I looked at the Selwyn River as a case study, but it’s a global issue. I just thought I could do something about it,” she said.

In the words of the Australian Water Association, “…Rodger’s project involved research into the causes of toxic cyanobacteria blooms and the development of a system that mitigates the risk. Cyanobacteria blooms plague global waterways and seriously impact the health of aquatic organisms, terrestrial animals, and humans. This threat is growing in prevalence alongside climate change.”

Rodger aimed to design a system that prevents uncontrolled cyanobacteria reproduction (a bloom event) while allowing natural populations to exist. Her design, the SolarCyanoSlayer, is also aimed to be self-sustaining for long-term implementation. It was made of biologically derived and recycled materials, reducing the embodied energy of construction. When placed in simulated eutrophic conditions, the invention was demonstrated to be highly effective in countering cyanobacteria blooms and subsequently improving overall water quality.

What did she want to achieve?

“There were three critical issues for me to deal with cyanobacteria,” she said. “The first is eutrophication, which represents too much phosphorus and nitrogen in the water. It normally comes about when the water is stagnant. The other two aspects are low oxygen levels and high water temperatures.”

When combined, these three factors result in the exponential growth of cyanobacteria. Targeting these was key to her research.

“The SolarCyanoSlayer is entirely made of recycled and biodegradable components,” she said. “This increases the viability of implementing it as something affordable and environmentally ethical. It’s made up of recycled PVC pipes, solar panels, biofilters and a pump.”

Rodger’s machine targets high mineral concentration with its biofilter. The solar panels power a low-level circulating pump and the oxygenator. The pump moves the water around to prevent stratification. Similarly, the oxygenator sucks in oxygen from the atmosphere and pumps it into the water as dissolved oxygen. The pump and oxygenator are not far removed from the small pumps utilised in small aquariums.

“The whole device is painted white. It’s a small decision, but the advantage is that there is less radiant heat transmitted into the water. This maintained the environmental quality of the device because it would not encourage further bacterial growth,” said Rodger.

When it comes to operating the biofilter, it is critical to prevent the growth of cyanobacteria. The oxygenator’s chemical reactions inhibit the bacteria’s development, reducing the algal blooms’ toxicity. It also works in tandem with the biofilter to prevent eutrophication.

Experimenting with cyanobacteria

Cyanobacteria is not something you can buy from a store. Rodger had to source it herself and then conduct her experiments. Collecting cyanobacteria was not a particularly difficult task.

“I went for a bike ride to a swamp that I know is prone to eutrophication and, therefore, algal blooms,” she said. “For the experiment, I had one tub with the cyanobacteria and a second tub as my control water. I also added some minerals to both tubs of water to try and simulate the conditions that would be present in farming dams. That meant adding fertiliser and minerals in the right concentration to ensure I could get as close as possible to what would happen in the real world.”

After adding those fertilisers and minerals, Rodger let both samples settle into place. That was when she was able to put her device into action. Solar power ensured that her devices would continue to operate without her presence, and she could check the progress where necessary.

The future of the SolarCyanoSlayer

Following her success at the Australian Water Awards, Rodger has received several offers to attend conferences and do work experience. However, she is concentrating on attending the Stockholm Junior Water Prize in late August as part of World Water Week in Sweden.

“If there is any interest from companies in commercialising the design, I’ll deal with that once I get back from Stockholm,” she said. “That is where it will be presented on a global scale, and I can potentially have a larger impact.”

Another aspect of Rodger’s research is looking at the bacteria created in waterways after bushfires. With the large amounts of organic material and minerals ending up in the water, the SolarCyanoSlayer could become invaluable.

“This year, I worked a bit more on cyanobacteria that bloom after bushfires,” she said. “It’s essentially black water after a bushfire – that’s when the water goes completely black. It’s a different type of bacteria that blooms, but that’s because there are so many minerals in the organic matter. Think about the volume of burnt leaves, trees, and other organic materials – they all end up in the waterway. Bacteria will break that down and use up all the oxygen in the water. As a result, the bacteria will be able to bloom exponentially from that because it’s such a reliable food source.”

The role of Meriden

Meriden School is located in Strathfield in Sydney’s inner west. An Anglican day school for girls, it has a strong focus on STEM subjects, which is reflected in the success of Meriden in the Stockholm Junior Water Prize. Meriden student Annabelle Strachan won in 2021 by studying and developing a bio-flocculant for reducing turbidity.

The school’s performance matches those of Newton Moore Senior High School (2001 and 2002 winners as Newton Moore College) and the Illawarra Grammar School (2017 and 2019 winners. It lags only behind the Queensland Academy for Health Sciences (2011, 2012, 2015, and 2016 winners).

“Meriden is very passionate about STEM,” said Richards. “We continuously support our student’s ideas and provide them with as many options as possible, both in and out of the classroom. We want the students to explore their passions and develop a wide range of skills. In our science classes, many of our lessons are very practical and hands-on. We want the girls to collaborate, ask many questions, and conduct those investigations. Relating them to real-world applications is where they succeed in STEM subjects.”

Related Articles:

Send this to a friend