Researchers from the NUS Tropical Marine Science Institute (TMSI) have found toxic bacteria residing on microplastics — pieces of plastic smaller than 5mm — collected from the coastal areas of Singapore in a first-of-its-kind study examining the bacterial community on microplastics in tropical waters.
“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,” said TMSI research lead and Senior Research Fellow Dr Sandric Leong. Microplastics in aquatic ecosystems also take longer to degrade due to the salt content and low ocean temperatures.
Dr Leong and TMSI and NUS Biological Sciences PhD student Emily Curren collected and examined 275 pieces of microplastics from the waters off Lazarus Island, Sembawang Beach and Changi Beach between April and July 2018, and discovered more than 400 different types of bacteria.
“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,” explained Emily.
The team discovered harmful bacteria species such as Photobacterium rosenbergii, often associated with coral bleaching; Vibrio, a major cause of wound infections in humans; and Arcobacter, known to cause gastroenteritis, as well as useful bacteria such as Erythrobacter, capable of degrading marine pollutants like hydrocarbons, and Pseudomonas veronii, which have been used to clean up oil spills.
The results of the study were published in the journal Science of the Total Environment in November 2018.
The researchers will conduct further studies to examine the origin of the bacteria species transported by the microplastics, which will help to identify non-native species that threaten the existing biodiversity and guide efforts in managing marine plastic pollution.
See press release.