Microplastics discovered in the deep, open ocean

This week researchers from NOC and Plymouth Marine Laboratory (PML) have embarked on a collaborative research expedition to further understand how tiny pieces of plastic litter are spreading in the open ocean and affecting life within.

This 26th Atlantic Meridional Transect (AMT) voyage will address a number of key questions, including: how much and what type of microplastic material is present in the Atlantic ocean and what is the physical impact of such on marine life, in particular the tiny organisms at the base of the marine food web that ingest these particles.

Professor Richard Lampitt and Dr Katsia Pabortsava, who lead microplastic research at NOC, said “There is considerable uncertainty about the concentration and characteristics of the many different types of microplastics and how these factors change over time and space. Our work in the vast open ocean spaces, hundreds of miles from land is a crucial part of this assessment. The deep sea is considered one of the major sinks of microplastic debris and so we intend to focus part of our research in this area. The deep sea also has a huge diversity of marine life, yet we do not know how much plastic is in this part of the ocean or how it may enter food chains or affect marine life there.”

The 26th voyage of AMT will be the first of its kind to follow such a long transect sampling for microplastics from the North to the South Atlantic. Travelling 600 miles daily aboard the RRS James Clark Ross research vessel, scientists will be analysing data from a large number of data points, covering vast areas including the remote, desert-like gyres in the centre of both the North and South Atlantic, otherwise generally untouched by other research efforts. Studying the gyres, systems of rotating ocean currents, will help scientists determine whether these areas are collecting and containing plastics or in fact breaking them down to distribute into the wider ocean. Through this research cruise scientists can continue ongoing research with aims to inform future policy and aid decision making on this topic.

This expedition follows a unique study by NOC scientists into the concentrations of microplastics in the open ocean, from surface to the sea bed. Preliminary findings already show microplastic presence in the top thousand metres of the water column at the Porcupine Abyssal Plain sustained ocean observatory in the North Atlantic. NOC scientists will soon analyse samples from three thousand metres depth collected at this site for the past twenty years using sediment traps – instruments analogous to rain gauges. They will also analyse unique samples from sediment traps stationed in the central North and South Atlantic subtropical gyres, which are giant swirls in the ocean where microplastics tend to accumulate.