Mapping of last continents

To begin, you should know that this phenomenon called 6th, 7th or 8th continent (but that means the same thing) according to the definition of continents ( is not recent.

Indeed, discharges into the ocean of garbage of all kinds or polluting actions occur for many years although in recent decades they are accelerated.

        I.   The genesis of the phenomenon

These masses more or less shapeless and diffuse, not always visible is the result of two factors: natural factors and human factors.

First start with the natural factor

                               A.    Oceanic circulation

Oceans are a dynamic system, which is mainly manifested in the thermohaline circulation. (« The adjective thermohaline derived from thermo referring to temperature and -haline referring to salt content » – from). These movements of huge water masses are caused by density differences between the different bodies of water. Simplified way, the density of water is determined by two factors: the temperature and salinity. The temperature is mainly following the warming sun of surface water bodies.

Increase of evaporation resulting and salinity. More water is warm and a little salt and it is light and vice versa.

Of course, these processes are much more complex and there are not only these factors come into account. Mapping presented in this phenomenon is therefore simplified.

This current, associed to Coriolis force creates huge vortex in oceans. This areas focus waters and also elements in water.


Secondly, we will discuss the anthropogenic factor

                               B.  Anthropogenic garbage production

Human activities (household, industrial etc…) produce a considerable amount of waste including a significant number end up in the Earth’s environment and oceans. This detritus is very diverse in terms of materials, shape size etc…

This offal does not have the same « lifetime » before their disappearance. From few weeks for papers to millenary for polystyrene or glass.

One type of waste is particularly problematic: plastic waste. Although the use of plastics goes back thousands of years, the development in the 18th century of synthetic materials and their widespread use in everyday life are that they have taken an important place in the trash.

           II.   « Discovers » and consequences

For many years, certain types of waste present in the marine community creates problems known to the public such as nylon fishing nets that derive or plastic bags swallowed by turtles that mistake them for jellyfish.

Many shocks photos were published to raise awareness about the phenomenon :







However, the proliferation of marine debris associated withthe thermohaline circulation and disturbing discoveries by scientists have recently initiated further research on the presence of waste in the oceans.

The discoveries of these waste vortex is not recent. For example, oceanographers of Sea Education Association have followed since 1986 the North Atlantic garbage patch and the Pacific trash vortex was discovered  ( in the  North Pacific Ocean gyre) in 1997 by Charles J. Moore : oceanographer and racing boat captain.

The worst is not always what is visible. Tiny plastic particles, especially after the fragmentation of plastic bags are present in large quantities. The large marine mammals can massively ingest plastic and starve. These wastes have serious consequences on marine ecosystems (toxic substances, ingestion by organisms and animals) as well as humans because we eat seafood (fish, crustaceans etc…). Ingestion of toxic substances (and bioaccumulation) and particulates by marine organisms have direct consequences on human health.
Like iceberg, the most important part of this are under the surface, up to 30m deep!

through the gyre

The disturbing findings of sea users (scientists and explorers especially) that produced shocking images helped limit the use or banning plastic bags in stores in twenty countries and in the European Union but many countries still use it.




        III.   Mapping of this phenomenon

Waste scopes are not clearly visible by satellite because of their characteristics. Thus, there was no accurate data on their location and their extensive and this problem only interested scientists and explorers.

Indeed, expeditions were launched to discover and study this phenomenon. The most famous project is the French scientific initiative called « Expedition 7e continent ». This name was chosen to put question and shock people. Start by Patrick Deixonne and Guyanese Association Scientific Ocean Logistic (OSL) in partnership with many research centers and laboratories known (CNES, NASA, NOAA, Marbec, LMGE etc…).

This project launched several expeditions (three successful to date) through these elements that constitute the « 7th Continent » with the following objectives :

  • Locate, map, quantify and identify, describe
  • See the consequences of this waste on the marine environment
  • Educate the world about this and disasters in the ocean
  • Educational programs for schoolchildren
  • Scientific Data collection to better understand the phenomenon and its « behavior » and in multiple aspects (chemistry, mathematics, biology etc…)

This is only a link in a vast scientific and educational project in the hope of mitigating the problem and find solutions.

Of course, the mapping of such a phenomenon is not accurate and is derived from observations and estimates.

The first card that we present was made by NASA from 35 years of data of its buoys. Simulating these data to better visualize the ocean dynamics and ocean gyres. We can easily imagine that wastes follow the same dynamics.


The second map is an interactive map showing results of estimates from 24 oceanographic studies campaigns.

Each dot on the map represents a 20kg plastic estimate. We note with fright the huge amount of plastic in the oceans potentially. A tab presents the estimate of the presence of waste by ocean and other details of the shipments.

sailing sea

sailing sea2

By clicking on the paths of shipments, you can access the details of the measures of a shipment based on collection sites. On the picture below, we can see count density of trash pieces according to their size or their weight.

sailing sea3

This site is very interesting because it enables a playful interaction with scientific data.
On the official website of « Expedition 7e continent », an educational space for teachers will retrieve documents but also maps and diagrams to educate school children and high school students. Like thereafter which show simulation of path a discarded at sea in northern europe.

Mapping of last continents - Final version

        IV.   The contribution of new technologies

Parallel to the shipments, a mobile application was developed in order to involve citizens to the problem of marine pollution. « A citizens application who geolocates and warning about wild rubbish ». Installed on a smartphone with GPS (Global Positioning System) – (Available on Android and iOS phones) – let users to report and documents (photos, videos) areas where there are waste.

















This would take loads trash before they end up in the ocean.

This application, beyond the citizenship dimension is a scientific vocation. It will gather data, map and study areas of pollution, understand their evolution.

All this strengthens the fight against pollution in the hope of mitigating this serious problem for us and our planet.