Floating wetlands offer cost-effective nature-based water treatment

University of South Australia

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Artificial or constructed floating wetlands involve planting wetland vegetation on floating rafts.

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Credit: CSIRO

A new international study has endorsed artificial floating wetlands as a sustainable and cost-effective solution for improving water quality in rivers, lakes and wastewater systems.

Led by scientists from Australia’s national science agency CSIRO and the University of South Australia, the team of researchers analysed 11 international constructed floating wetlands (CFW) projects in Australia, Pakistan, Canada and the USA.

Artificial or constructed floating wetlands involve planting wetland vegetation on floating rafts, mimicking a natural ecosystem that removes nutrients, sediments and other pollutants from the host water body.

The researchers found that capital costs for floating wetlands ranged from as little as A$22 per square metre, to more than A$3800 per square metre, depending on design, location and purpose.

Operating costs varied from A$0.76 to A$274 per square metre each year.

Lead author, CSIRO Research Engineer and UniSA Adjunct Research Fellow Dr John Awad, says the findings will help councils, utilities and water managers better understand the economic feasibility of floating wetlands compared to conventional treatment systems which use physical, chemical and biological processes.

“Floating wetlands mimic the functions of natural ecosystems, filtering nutrients and pollutants through plant roots and microbial communities,” Dr Awad says.

“But until now, there’s been limited data on what they actually cost to build, maintain and operate at scale. Our study shows that while costs vary, floating wetlands can be competitive with other engineering treatment options, especially for nitrogen removal.”

On average, the cost of removing nitrogen was between A$15 and A$183 per kilogram – consistently cheaper than removing phosphorus, which ranged from $A23 to A$4979 per kilogram.

“Scale matters,” says Dr Awad. “Larger wetlands reduced the cost per kilogram of nutrients removed, making them more economical over time. Climate also plays a role. Wetlands in warmer regions had longer growing seasons and higher pollutant removal rates.”

Floating wetlands are increasingly being trialled to treat domestic wastewater, stormwater and polluted urban rivers.

In Australia, schemes in the Sunshine Coast region and Victoria have targeted wastewater and stormwater, while projects in the United States have incorporated community spaces, ecological restoration and even floating boardwalks.

Study co-author, UniSA Professor Simon Beecham, says the technology has added advantages beyond water quality.

“Floating wetlands can be retrofitted into existing lakes and stormwater ponds without the need for costly land acquisition,” Prof Beecham says.

“They also provide habitat for birds and aquatic life, improve urban amenity, and may even contribute to carbon sequestration.”

The research team highlighted significant cost differences between projects in developed and developing countries. For example, wetlands built in Pakistan cost just A$13-20 per square metre – a fraction of the expense in Australia and North America – due to lower labour and material costs.

“Understanding these variations helps governments and planners adapt the technology to local conditions,” according to Dr Awad.

“It also shows that floating wetlands could be a particularly valuable option in low- and middle-income countries, where affordable, low-energy treatment systems are urgently needed.”

The authors say floating wetlands are not a silver bullet but should be considered as part of a broader suite of water treatment options.

‘Assessing the costs of constructed floating wetlands for the treatment of surface waters and wastewater’ is published in ACS ES&T Water. DOI: 10.1021/acsestwater.5c00439

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Journal

ACS ES&T Water

DOI

10.1021/acsestwater.5c00439 

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

Assessing the costs of constructed floating wetlands for the treatment of surface waters and wastewater

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The importance of a leader–follower relationship for performing tasks

Having a good leader–follower relationship matters, but only when people spontaneously choose their roles

Role specialization enables superior task performance by human dyads than individuals

Osaka Metropolitan University

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Left image shows the paired condition where two people try to keep the rod horizontal in virtual space by operating a robot arm. Right shows the solo condition where one person operates both arms.

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Credit: Osaka Metropolitan University

As most of us have experienced, when multiple people work together, things sometimes turn out better than doing the same task alone. Then, there are the other times, when cooperation actually seems to hinder progress, making things much more inefficient.

To understand why this ‘cooperative advantage’ manifests in some cases but not in others, a research group led by Assistant Professor Asuka Takai of the Graduate School of Engineering at Osaka Metropolitan University conducted a task where participants used a robotic arm to transport a rod while keeping it horizontal. The participants were told that the task would stop if the rod’s tilt exceeded a certain threshold. They compared performance between groups of two people working together and people performing the task alone.

To examine the effect of teamwork, the group created two conditions. In the ‘symmetric’ condition, the axis of the rod was centered, meaning the task could be equally split between the two arms. In the other ‘asymmetric’ condition, the rotation axis was off-center because the arms were different lengths. This meant that the participant assigned the shorter arm typically had to lead the one assigned the longer arm.

Under the asymmetric condition, the paired participants learned to adjust their movements with each trial to minimize the tilt of the rod. A natural division of roles emerged, with one partner taking the lead and the other providing support, leading to superior performance by the pairs compared to the individuals.

On the other hand, under the symmetric conditions, no division of roles was observed between partners. Under these conditions, pairs that did not exhibit clear role differences required more transportation time and trials than individuals.

Overall, pairs outperformed individuals when the two participants naturally assumed different roles, whereas individuals performed better than pairs when no such role differentiation occurred.

“The study confirmed that when a ‘leader–follower’ relationship naturally emerges under physically asymmetric conditions, cooperative performance improves,” Professor Takai explained. “Our findings suggest that role specialization, rather than paired interaction per se, was a key factor underlying superior performance.”

The group hopes that future research will explore how asymmetric dynamics, which foster leader–follower dynamics, could similarly enhance performance in rehabilitation and human–robot settings.

“This discovery is expected to be applied to collaborative design between humans and robots,” Professor Takai said. “A robot needs to know when to take on a task itself or hand it over to a human, which may require understanding subtle differences in how each can contribute to the task.”

The study was published in The International Journal of Robotics Research.

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About OMU 

Established in Osaka as one of the largest public universities in Japan, Osaka Metropolitan University is committed to shaping the future of society through “Convergence of Knowledge” and the promotion of world-class research. For more research news, visit https://www.omu.ac.jp/en/ and follow us on social media: X, Facebook, Instagram, LinkedIn.

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Journal

The International Journal of Robotics Research

DOI

10.1177/02783649251363274 

Method of Research

Experimental study

Subject of Research

People

Article Title

Role specialization enables superior task performance by human dyads than individuals

 

The Crown Princess of Sweden honoured with a professorship in biodiversity

University of Gothenburg

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Crown Princess Victoria of Sweden.

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Credit: Linda Broström/Kungl. Hovstaterna

The University of Gothenburg is establishing the Crown Princess Victoria Professorship in Biodiversity. The professorship is a gift ahead of the Crown Princess's 50th birthday in 2027, in collaboration between Carl Bennet AB and the University of Gothenburg.

Biodiversity is a growing field of research, and the University of Gothenburg now has the opportunity to contribute more effectively through a new professorship in biodiversity established in the Crown Princess's name. The Crown Princess has repeatedly expressed her belief that the diversity of animals and plants, both above and below the water's surface, is an important area.

“The University of Gothenburg conducts extensive research in biodiversity, and we are delighted to receive this support from Carl Bennet AB for a professorship that will enable us to raise our ambitions,” says Göran Hilmersson, Dean of the Faculty of Science and Technology, which will host the professorship.

Strong research leader

However, the professorship involves more than one person; the idea is that researchers will be employed at several faculties, as the subject has applications in several subject areas. One advantage in this context is that the University of Gothenburg already has a centre for biodiversity, GGBC, the Gothenburg Global Biodiversity Centre.

Carl Bennet AB's support of 20 million Swedish kronor is matched by the University of Gothenburg, which is contributing the same amount to the professorship.

“Our vision is for the professor to be a strong research leader and ambassador for the interdisciplinary field, thereby helping to lead the way towards a sustainable future. Collaboration across disciplinary boundaries, combined with active engagement with decision-makers and other stakeholders, will enable groundbreaking research in biodiversity,” says Malin Broberg, Vice-Chancellor of the University of Gothenburg.

The search for the most suitable candidates for the new professorship is now underway. The position will be advertised in the coming days, and the recruitment process is expected to be completed in time for the name of the professorship holder to be announced on International Day for Biological Diversity on 22 May 2026. 

Here you will find the advertisement for the professorship in biodiversity.

 

Dependence of tipping points in the global system - Four central climate components are losing stability

Technical University of Munich (TUM)

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Four of the most important interconnected parts of the Earth's climate system are losing stability. This is shown by an international scientific study based on observational data published in Nature Geoscience. The researchers succeeded in highlighting the warning signals for destabilization of the Greenland Ice Sheet, the Atlantic Meridional Overturning Circulation (AMOC), the Amazon rainforest, and the South American monsoon system.

"We now have convincing observational evidence that several interconnected parts of the Earth system are destabilizing," says lead author Prof. Niklas Boers from the Technical University of Munich (TUM) and the Potsdam Institute for Climate Impact Research. "This means that these systems may be approaching critical thresholds that, if crossed, could trigger abrupt and irreversible changes with severe consequences," adds Prof. Tim Lenton from the University of Exeter.

The researchers' major concern is that these climate systems are not isolated. The systems interact with each other via the oceans and the atmosphere, which can lead to interactions and feedbacks. In the worst-case scenario, this destabilizes them and intensifies the negative consequences for the global climate system. At the same time, these effects could mask genuine warning signals and make tipping points even more difficult to predict.

"Unlike previous studies that focus on individual Earth system components, this new research zooms out to analyze them together as part of a larger, interconnected system," adds co-author Dr. Teng Liu, also from TUM.

Analysis using a mathematical method

While current climate models are not yet able to simulate these complex dynamics reliably, empirical data offers an important way to monitor changes already underway. To identify and track signs of destabilization, the researchers developed a mathematical method that analyzes how systems recover from disturbances. Applying this method to empirical data reveals the ongoing stability loss in key Earth system components.

"While the exact thresholds at which tipping points may be crossed remain highly uncertain, the evidence clearly points toward increasing risk as temperatures rise. With every tenth of a degree of additional warming, the likelihood of crossing a tipping point grows. That alone should be a powerful argument for immediate and decisive reduction of greenhouse gas emissions," emphasizes Prof. Niklas Boers.

Global monitoring system required

In addition to reducing emissions, the researchers are calling for the development of a global monitoring system to track the stability of major Earth system components. Satellite-based observations, particularly of vegetation and ice melt, will play a central role. This study not only underscores the urgency of building such a system, it also provides the methodological framework to support it.

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Journal

Nature Geoscience

DOI

10.1038/s41561-025-01787-0 

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

Destabilization of Earth system tipping elements

Article Publication Date

1-Oct-2025