Tracking marine plastic drift from space

In a hi-tech version of throwing out messages in bottles, prototype trackable buoys were deployed in the waters off Indonesia, whose myriad of islands results in some of the most complex, unpredictable currents on Earth.

Made from wood for maximum sustainability, the buoys were developed by French organization CLS, Collecte Localization Satellites. A subsidiary of French space agency CNES, CLS is best known for overseeing the satellite-based tracking of tagged , buoys and fishing fleets using its long-running Argos geopositioning system, which performs satellite navigation fixes and returns them to CLS via satellite link.

CLS made use of previous experience of marine plastic litter in Indonesia for the buoy deployments. It has previously teamed up with the Indonesian Ministry of Marine Affairs and Fisheries to help guide waste collection efforts—the country's national marine pollution plan pledges to reduce plastic waste by 70% by the end of 2025.

Together with the tracking buoys, the MARLISAT also involves harnessing Earth observation imagery to detect plastic sources and forecast marine plastic litter's motion and areas of accumulation using an existing CLS ocean drift model called MOBIDRIFT.

MARLISAT partner Pixalytics [LINK: https://www.pixalytics.com/ ] in the UK has meanwhile been developing a machine learning algorithm able to detect plastic accumulation along beaches and ocean hotspots from satellite images. Credit: Pixalytics

Together with the tracking buoys, the MARLISAT project also involves harnessing Earth observation imagery to detect plastic sources and forecast marine plastic litter’s motion and areas of accumulation using an existing CLS ocean drift model called MOBIDRIFT. Credit: CLS

This plastic-free WoodMark buoy was designed for the MARLISAT project. Just 11cm by 7 cm in size, the wooden transmitter-housing buoy has a drag reducing shape and is designed to be tethered to objects of interest, such as plastic waste. Credit: CLS

Monitoring this plastic can be very difficult from Earth’s surface, as it is impossible to see much of the ocean at once. But satellites with very high-resolution cameras and wide fields of view are changing our ability to monitor plastic waste, and ESA's Discovery & Preparation is supporting studies that investigate the best way of doing so. Credit: ESA - ScienceOffice.org