Nav: Home

NUS marine scientists find toxic bacteria on microplastics retrieved from tropical waters

February 11, 2019

A field survey conducted by a team of marine scientists from the National University of Singapore (NUS) has uncovered toxic bacteria living on the surfaces of microplastics, which are pieces of plastic smaller than 5 millimetres in size, collected from the coastal areas of Singapore. These bacteria are capable of causing coral bleaching, and triggering wound infections in humans.

The NUS team also discovered a diversity of bacteria, including useful organisms - such as those that can degrade marine pollutants like hydrocarbons - in the plastic waste.

Dr Sandric Leong, research lead and Senior Research Fellow at the NUS Tropical Marine Science Institute (TMSI), said, "Microplastics form a large proportion of plastic pollution in marine environments. Marine organisms may consume bits of microplastics unintentionally, and this could lead to the accumulation and subsequent transfer of marine pathogens in the food chain. Hence, understanding the distribution of microplastics and identifying the organisms attached to them are crucial steps in managing the plastic pollution on a national and global scale."

This study is the first to examine the bacterial community on microplastics found in tropical coastal regions. The results were first published in the journal Science of the Total Environment on 17 November 2018.

Small plastics, big problem

There are currently more than 150 million tons of plastics in the ocean. Microplastics, in particular, pose an evident problem as many marine organisms, such as shrimps, mussels and fish, often mistake these tiny plastics for food.

Compared to microplastics on land, microplastics in aquatic ecosystems take a much longer time to degrade due to the presence of salt and a lower temperature in the ocean. As a result, they present a habitable environment for marine biota to colonise. Yet, despite their prevalence, the distribution of microplastics along the coasts of tropical regions is not well studied.

Dr Leong and Ms Emily Curren, a PhD student from TMSI and the Department of Biological Sciences at the NUS Faculty of Science, embarked on a six-month study to examine the bacterial communities on microplastics collected from coastal regions of Singapore.

Diverse bacterial communities living on microplastics

Between April and July 2018, the research team collected and examined 275 pieces of microplastics from three beaches along the coastline of Singapore, namely Lazarus Island, Sembawang Beach, and Changi Beach. By using high-throughput sequencing techniques, the team discovered more than 400 different types of bacteria across all the microplastics collected.

Species of the bacteria Erythrobacter, which is capable of degrading plastic, and bacteria species Pseudomonas veronii, which have been used to clean up oil spills, were found. "Given the predicted increase in plastic waste contamination in oceans, the discovery of such bacteria provides important nature-friendly alternatives for the mitigation of plastic pollution and toxic pollutants such as hydrocarbons," said Ms Curren.

In contrast, the bacteria Photobacterium rosenbergii, often associated with coral bleaching and disease, was also identified. The proliferation and accumulation of this bacterium could be detrimental to the coral reefs in Singapore as the southern strait is characterised by multiple coral communities with great biodiversity that are under conservation.

The research team also uncovered species of marine Vibrio, a major cause of wound infections in humans, and species of Arcobacter, known to cause gastroenteritis in humans. "As the microplastics we studied were collected from locations easily accessible to the public and in areas widely used for recreation, the identification of potentially pathogenic bacteria would be important in preventing the spread of diseases," elaborated Ms Curren.

Future studies to identify bacteria sources

This study demonstrates that microplastics are a rich habitat that is home to many types of bacteria, including toxic ones. The NUS research team will conduct further studies to examine the origin of the bacteria species transported by the microplastics. This will allow the identification of non-native species that threaten the existing biodiversity, and provide insights on managing the urgent issue of marine plastic pollution.
-end-


National University of Singapore

Related Bacteria Articles:

Conducting shell for bacteria
Under anaerobic conditions, certain bacteria can produce electricity. This behavior can be exploited in microbial fuel cells, with a special focus on wastewater treatment schemes.
Controlling bacteria's necessary evil
Until now, scientists have only had a murky understanding of how these relationships arise.
Bacteria take a deadly risk to survive
Bacteria need mutations -- changes in their DNA code -- to survive under difficult circumstances.
How bacteria hunt other bacteria
A bacterial species that hunts other bacteria has attracted interest as a potential antibiotic, but exactly how this predator tracks down its prey has not been clear.
Chlamydia: How bacteria take over control
To survive in human cells, chlamydiae have a lot of tricks in store.
Stress may protect -- at least in bacteria
Antibiotics harm bacteria and stress them. Trimethoprim, an antibiotic, inhibits the growth of the bacterium Escherichia coli and induces a stress response.
'Pulling' bacteria out of blood
Magnets instead of antibiotics could provide a possible new treatment method for blood infection.
New findings detail how beneficial bacteria in the nose suppress pathogenic bacteria
Staphylococcus aureus is a common colonizer of the human body.
Understanding your bacteria
New insight into bacterial cell division could lead to advancements in the fight against harmful bacteria.
Bacteria are individualists
Cells respond differently to lack of nutrients.

Related Bacteria Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Setbacks
Failure can feel lonely and final. But can we learn from failure, even reframe it, to feel more like a temporary setback? This hour, TED speakers on changing a crushing defeat into a stepping stone. Guests include entrepreneur Leticia Gasca, psychology professor Alison Ledgerwood, astronomer Phil Plait, former professional athlete Charly Haversat, and UPS training manager Jon Bowers.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".