Francois Galgani Oceanographer and biologist who serves as Project Manager and Manager of the Bastia site at France’s Research Institute for the Exploration of the Sea (Ifremer)
"There are currently more than 150 million metric tons of waste in our seas and oceans, and over 80% of this waste is plastic. More than 10 million metric tons are added every year. Most of the waste washed out to sea comes from land-based source (rivers)."
Marine Pollution: Diverse Responses
For millions of years, water in the world’s large ocean basins has been circulating on the surface, sometimes causing large areas of convergence where weaker currents allow for build-ups of floating waste. Build-up can be found in all oceans but also, less commonly, in closed areas such as the Mediterranean.
In 20,000 Leagues Under the Sea, Jules Verne’s Nautilus crosses the Sargasso Sea where the crew finds “brown weeds […], tree trunks ripped from the Rocky Mountains or the Andes and sent floating down the Amazon or the Mississippi, numerous pieces of wreckage, remnants of keels or undersides, bulwarks staved in”. Passive animals such as small turtles, eels and plankton have been swept along in the flow.
Since the 1950s, discarded plastics have considerably increased the phenomenon, and now account for more than 80% of total volumes. Contrary to what is often imagined, only 1% or 2% of this waste floats on the surface, and a similarly small amount washes up on beaches. Almost all of the waste lies on the sea floor; there is hardly any in the water column. The waste varies greatly in size and can be as tiny as microplastics (from 1 millimeter to 1/1000 of a millimeter) and even nanoplastics due to the slow decomposition of polymers.
What Are the Impacts?
This situation simultaneously impacts the environment, the economy and society.
Lost or abandoned fishing nets are a major environmental problem. Even if torn, these nets, which are now made from plastic, continue to catch or strangle marine animals, including large ones such as seals, dolphins and even whales. Almost 100% of the waste in the Azores is generated by fishing. In the Gulf of Lion, it is estimated that 2% to 3% of the fish stocks exploited by fishing fleets have been lost, not to mention all the other species.
Swallowing plastic particles is a phenomenon that affects all marine species, either because they filter the water or because they eat prey that has swallowed them. Turtles and birds from the procellariformes family are particularly sensitive to this problem. The impact on humans is less obvious: a Korean study estimated that only 5% of the microplastics we ingest come from seafood, while 9% comes from water and 85% from the air we breathe.
A third environmental impactAny change to the environment, whether adverse or beneficial, wholly or partially resulting from human activity... that is lesser known to the general public is the irregular movement of species, from bacteriaTiny living organisms that are made up of a single cell that does not have a distinct nucleus, such as a prokaryotic cell... to crustaceans and mollusks. After the March 2011 tsunami in Japan, nearly 300 species of macrofauna arrived in North America, carried by the waste. While such genetic mixing may have some positive aspects, it also contributes to the transmission of disease and can completely alter a species’ ecosystem.
On the economic front, the United Nations estimates that €8 million in financial losses are incurred worldwide every year due to events ranging from maritime accidents caused by shipwrecks to the clean-up of polluted coastlines.
Such a massive, global phenomenon inevitably calls for diverse solutions.
One avenue is to raise awareness among the population, especially young people. Ships that set out into the middle of the ocean to recover waste have no real quantitative impact and are above all human adventures. However, they do contribute to universal awareness, without which nothing is possible.
Another possibility is to give a “value” to waste. It is unrealistic to think that consumers, manufacturers or communities of any kind will make financial efforts or investments if there are no benefits associated with the collection or treatment of waste.
Consider these two examples. Fishing nets are often very expensive and if it were possible to salvage large pieces, repair them and sell them, this could become a viable business. A company in the Adriatic already specializes in this field. Likewise, cleaning up a tourist attraction costs a local community money but restores the value of the site, either in terms of tourism or heritage.
We’re not going to get rid of plastics. They are essential to make aircraft and vehicles lighter, improve medical equipment, insulate buildings and improve the safety of food products. But it is possible to curb the use of single-use packaging, which has no value, and to develop circular economy systems.
It is also essential to increase the number of recyclable materials. Research such as that on PDK, which can be disassembled into its original fibers, could give value to fully recyclable plastics. DepositAn accumulation of natural resources, such as oil, natural gas, coal, uranium, metal ore or another commodity... systems can appeal to both consumers, who may be interested in collecting used plastics, and the recyclingAny waste treatment process that uses materials from identical or similar end-of-life products or manufacturing waste to produce new products. industry, which is attracted by the prospectA potential hydrocarbon deposit. Explorationists seek to locate prospects, determine their configuration and size... of resale. Recovering waste on a large scale on land would dry up the plastic streams that end up in the seas and oceans.
Francois Galgani is an oceanographer and biologist who serves as Project Manager and Manager of the Bastia site at France’s Research Institute for the Exploration of the Sea (Ifremer). With 35 years of experience researching oceanography and environmental sciences (marine pollution, ecotoxicology and marine waste), he is a member of the European Commission’s “Horizon Europe – Healthy Oceans, Freshwaters and Coasts” initiative. Francois has also participated in numerous programs with the United Nations and other international organizations and has led several oceanographic campaigns throughout the Mediterranean.