Urgent need to defuse the microplastics time bomb

The threat posed by microplastics to the health of the marine environment and to public health is still low on the radar, having so far failed to captivate the public's attention. Marine scientists have long been talking about the sheer magnitude of this virtually unknown and unheeded threat, but their message is simply not getting through. For this reason, the visit last week by the research vessel Tara was a red letter day as it bolstered awareness about the issue. Tara is renowned for its gruelling expeditions around the world's oceans, but this year's seven-month-long expedition will meander through 16,000km in the Mediterranean Basin, sampling day and night with tailor-made nets known as Manta nets, in order to assess the density of microplastics in different parts of the Mediterranean. Microplastics, as the name implies, are small, with some members of the scientific community defining them as particles being smaller than 1 mm while others define them as being smaller than 5mm. In view of their small size, they have a knack of being ingested by filter-feeding marine species, such as mussels, or of being engulfed by planktonic species. This could have various consequences, including the hapless marine species in question developing a blockage or physical damage to their digestive tract or absorbing toxic chemicals into their bloodstream.