When tiny pieces of plastic are ingested by marine organisms, they can accumulate and be transferred into the food chain – ScienceDaily

The NUS team has also discovered a variety of bacteria, including beneficial organisms – such as those that can degrade marine pollutants such as hydrocarbons – in plastic waste.

Dr. Sandric Leong, Senior Research Fellow and Researcher at NUS, said, "Microplastics account for a large proportion of plastic pollution in marine environments, and marine organisms can inadvertently consume fragments of microplastics, which could lead to the development of microplastics. accumulation and subsequent transfer of marine pathogens into the food chain.Therefore, understanding the distribution of microplastics and identifying organisms related to them are crucial steps in the management of plastic pollution at the same time. nationally and globally. "

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 Total environmental science November 17, 2018.

Small plastics, big problem

There are currently more than 150 million tons of plastics in the ocean. In particular, microplastics are an obvious problem because many marine organisms, such as shrimp, mussels and fish, often confuse these tiny plastics with food.

Compared to microplastics used on land, microplastics in aquatic ecosystems take much longer to degrade due to the presence of salt and lower temperature in the ocean. As a result, they provide a livable environment for marine biota to colonize. However, despite their prevalence, the distribution of microplastics along tropical coastlines is not well studied.

Dr. Leong and Ms. Emily Curren, a Ph.D. student at TMSI and the Department of Biological Sciences at the NUS Faculty of Science, have launched a six-month study of bacterial microplastic communities collected in coastal areas of Singapore.

Various 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 Singapore coast, namely Lazarus Island, Sembawang Beach and Changi Beach. Using high throughput sequencing techniques, the team discovered more than 400 different types of bacteria on the whole collection of microplastics.

Species of the bacteria Erythrobacter, able to degrade plastics and bacteria Pseudomonas veronii, which were used to clean up oil spills, were discovered. "Given the predicted increase in ocean contamination by plastic waste, the discovery of such bacteria offers important, nature-friendly alternatives for the mitigation of plastic pollution and pollution." toxic pollutants such as hydrocarbons, "Curren said.

In contrast, bacteria Photobacterium rosenbergii, often badociated with coral bleaching and disease, has also been identified. The proliferation and accumulation of this bacterium could be detrimental to Singapore's coral reefs as the southern strait is characterized by multiple coral communities with high biodiversity and conservation status.

The research team also discovered species of marine species. Vibrio, a major cause of human wound infections, and species of Arcobacter, known to cause gastroenteritis in humans. "As the microplastics we studied were collected in places easily accessible to the public and in recreational areas, identifying potentially pathogenic bacteria would be essential to prevent the spread of disease," Curren said.

Future studies to identify sources of bacteria

This study demonstrates that microplastics are a rich habitat that supports many types of bacteria, including toxic bacteria. The NUS research team will conduct further studies to examine the origin of bacteria species carried by microplastics. This will identify non-native species that threaten existing biodiversity and provide information on managing the urgent problem of marine plastic pollution.