Microplastic rainbow © JOAN COSTA


The color characterization of plastic debris is often included in studies on litter pollution. However, the comparability and usefulness of this information is limited by methodology or observer subjectivity. In this paper, we propose a systematic and semiautomatic method to analyze colors, providing a wide empirical background to further the interpretation and applicability of the color information. The distribution of colours in a sample is mainly related to the time of exposure time to solar radiation, and could be used as proxy of plastic ageing in the near future. Sadly, the selective ingestion of plastic by visual predators appears to be also a significant modulator of the color distributions.

Download original paper


Pictured is a fragment of expanded polyurethane foam collected from the surface waters of the South Pacific Ocean. The 3-cm fragment is colonized by tentacled terebelid worms and shelled gastropods © JOAN COSTA

The global system of litter accumulation in the 5 great ocean gyres

In 2014, based on the Malaspina 2010 circumnavigation, MALUCA provided the first global map and approximation of the magnitude of the plastic pollution in surface waters of the oceans. The study made a puzzling discovery, the plastic afloat is less than 1% of the total amount entering the ocean. A fragmentation model for plastic debris showed that an important fraction of the missing plastic corresponds to tiny fragments (few millimeters in length or smaller), and a disturbing possibility: these plastic fragments can be mistaken with plankton and be regularly eaten by the organisms in the base of the marine trophic chain.

Download original paper

In the news

     First of its kind map reveals extent of ocean plastic  
By LAURA PARKER I National Geographic  I July 16, 2014

          Ninety-nine percent of the ocean´s plastic is missing
By ANGUS CHEN I Science I June 30, 2014

Fishing boats in Lesvos, Greece © Andrés Cózar

The Mediterranean is the 6th great plastic accumulation discovered in the planet

In 2015, from an expedition across the whole Mediterranean basin, MALUCA classified for the first time the Mediterranean as a great plastic accumulation zone of plastic, comparable to those described in the middle of the five ocean basins. Mediterranean Sea was the 6th great accumulation discovered, and opened up the possibility of there being other great accumulations of plastic debris in semienclosed seas.

Mediterranean Sea represents less than 1% of the global ocean surface, but it houses around 10% of all marine species and provides fundamental incomes for the surrounding countries through seas-based tourism and fishing industry. We predicted that the effects of plastic pollution would be particularly harmful in this region due to the biological wealth and concentration of economic activities.

Download original paper

In the news

    Mediterranean Sea 'accumulating zone of plastic debris' 
By HELEN BRIGGS I BBC  I April 2, 2015

Microplastics found in Arctic waters © Elisa Martí & Andrés Cózar.

The plastic we dump into the oceans reaches the Arctic

It was believed that marine litter was primarily a concern in temperate and tropical regions. Not at all. In 2017, an expedition around the North Pole on board TARA vessel revealed the migration of the floating plastic disposed into the oceans towards the pristine waters of the Arctic Ocean. This poleward migration of plastic involves the so-called Thermohaline Circulation, a global conveyor belt currently known for redistributing heat across the global ocean and now connecting the Arctic with sources of marine litter from other parts of the world. More than ever before, preserving the Arctic requires preserving the planet.

Download original paper

In the news

    Trillions of Plastic Bits, Swept Up by Current, Are Littering Arctic Waters 
By TATIANA SCHLOSSBERG I The New York Times  I Apr 19, 2017

    The pristine Arctic has become a garbage trap for 300 billion pieces of plastic 
By CHRIS MOONEY I The Washington Post  I April 19, 2017

The Tara research vessel seen from the mast during the Arctic circumpolar expedition © Francois Aurat.

Other contributions


Marine Litter Windrows: A Strategic Target to Understand and Manage the Ocean Plastic Pollution
Cózar et al.  I  Frontiers in Marine Science

Overview of global status of plastic presence in marine vertebrates
López-Martínez et al.   Global Change Biology

Unravelling spatio-temporal patterns of suspended microplastic concentration in the Natura 2000 Guadalquivir estuary (SW Spain)
Bermúdez et al.  I  Marine Pollution Bulletin

Floating macrolitter leaked from Europe into the ocean
González-Fernández et al.  I  Nature Sustainability

An inshore–offshore sorting system revealed from global classification of ocean litter
Morales-Caselles et al.  I  Nature Sustainability


Litter windrows in the south-east coast of the Bay of Biscay: an ocean process enabling effective active fishing for litter
Ruiz et al.  I  Frontiers in Marine Science

The colors of the ocean plastics
Martí et al.  I  Environmental Science & Technology

The physical oceanography of the transport of floating marine debris
van Sebille et al.  I  Environmental Research Letters


Surface water circulation develops seasonally changing patterns of floating litter accumulation in the Mediterranean Sea
Macías et al.  I  Marine Pollution Bulletin

An interlaboratory comparison exercise for the determination of microplastics in standard sample bottles
Isobe et al.  I  Marine Pollution Bulletin

Barboza et al.  I  World seas: An environmental evaluation, Academic Press

Guidelines for Harmonizing Ocean Surface Microplastic Monitoring Methods Version 1.0.
Michida et al.  I  Ministry of Environment of Japan

Measuring marine plastic debris from space: initial assessment of observation requirements
Martínez-Vicente et al.  I  Remote Sensing


Characterization of microplastic litter from oceans by an innovative approach based on hyperspectral imaging
Serranti et al.  I  Waste Management


Low abundance of plastic fragments in the surface waters of the Red Sea
Martí et al.  I  Frontiers in Marine Science


Changes in the floating plastic pollution of the Mediterranean Sea in relation to the distance to land
Pedrotti et al.  I  PloS One

Breaking Down the Plastic Age
Baztan et al.  I  Fate and Impact of Microplastics in Marine Ecosystems, Elsevier