‘Microplastics’ are microscopic plastic fragments, fibres and granules which are polluting our oceans.
This plastic debris can arrive in the ocean directly, for example through every day products which are washed down our sinks, or indirectly via the breakdown of large items of plastic. Microplastic marine litter pose a risk to oceanic animals throughout the food web.
Even zooplankton, the tiniest animals in the sea, are exposed to the global environmental challenge of microplastics. Many of these animals are ‘filter feeders’ indiscriminately feeding on whatever is available in the ocean, including microplastics. Because plankton underpins the whole marine food chain, ingested plastic can be accumulated up through the chain when the plankton is eaten by larger animals.
Monitoring microplastic levels is fundamental to our understanding of how much of a risk these fragments pose to marine life. There have been studies in the past using plankton nets to quantify microplastics, however the presence of plastic in the samples is usually masked by the plankton itself. To combat this, PML scientists developed a method to isolate the plastics from the samples. This technique removed the biological material from the sample without destroying the plastic, thus allowing for much more accurate measurement of small plastic debris. It also enabled the scientists to identify extremely small, microplastic debris of less than 0.1 mm in size, which has been so far poorly documented in field studies.
It is expected that the method used in this research will be highly applicable to future plankton trawl samples where quantifying microplastics is the focus of the study. To read the open access paper ‘Isolation of microplastics in biota-rich seawater samples and marine organisms’ please click here.