From France’s Atlantic coast to the Spanish Mediterranean, marine industries are finding new ways to turn their waste into treasure.
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00:00In southwest France's Arcachon Bay, oyster farming is a centuries-old tradition.
00:07Some of the world's finest oysters are cultivated here using time-honored techniques.
00:13Farmers like Benjamin Legeran carefully sort their stocks.
00:17It takes over three years to grow an oyster, but many don't survive due to disease, predators and other natural challenges.
00:25For every oyster that reaches our plate, an empty shell is left behind.
00:55The regional shellfish committee collects discarded shells from farmers, bringing them to storage sites like this one.
01:03Around 2,000 tons pass through here each year.
01:08Rich in calcium, these shells aren't just waste, they're raw materials.
01:13All of them will be repurposed for construction, chicken feed additives and even fine porcelain.
01:19Yes, it's their fight.
01:20Yes, but I don't want to stop it.
01:21We're looking for new developments to increase the added value of this product and also try to develop innovative projects with more and more, if possible,
01:30of course circuits with re-employment locally on the Basin d'Arcachon or on our own territory.
01:35One promising innovation is using shells to create sustainable concrete.
01:40Traditional concrete production emits massive CO2, but Professor David Grégoire's team at the University of Pau and Pays de l'Adour
01:48has reduced these emissions by using low-carbon cements and crushed seashells instead of sand and gravel in the concrete mix.
01:57They work with local oyster and scallop shells, as well as pearl oysters from French Polynesia,
02:03whose unique properties enhance the concrete.
02:05At the famous Dune de Pila, Europe's tallest city of Pays de l'Adour,
02:35Sand Dune, visitors already walk on oyster-based concrete.
02:39This 100-metre pathway welcomes millions each year.
02:44Researchers produced these concrete slabs at a nearby factory using locally-sourced shells,
02:48an ideal example of a circular economy where one industry's waste becomes another's resource.
02:54This busy site is a perfect test ground, and so far, the shellfish concrete is holding up well under heavy foot traffic.
03:02We have really had a circular economy plan to valorise the waste produced in this region on this site,
03:13which also allows us to make clear this plan with a large public plan,
03:19since this site is extremely visited.
03:21The test location itself reinforces the project's environmental message.
03:27The Dune de Pila has become a symbol of coastal vulnerability.
03:32But with a fresh take on environmental challenges, the world is your oyster.
03:40Take Gandia on Spain's Mediterranean coast.
03:43Here, old fishing nets don't just pile up on docks, end up in landfills or drift at sea.
03:50The Spanish company, Gravity Wave, with support from European funding,
03:55partners with fishers to collect and repurpose these nets, giving them new life.
04:00Collected nets go to sorting facilities where workers separate them by colour and plastic type.
04:23That's mainly high-density polyethylene, but also nylon and polypropylene.
04:30These durable marine plastics make excellent raw materials, though processing them is labour-intensive.
04:53The nets are transformed into solid plastic sheets, waterproof, sun-resistant and highly durable,
05:07making them ideal for outdoor use.
05:11Gravity Wave, based in CALP, showcases final products like office desks,
05:16stadium seats and street benches that can last for decades and then be recycled again.
05:23Plastics, once used to catch fish in these waters, now continue to serve the coastal community,
05:36helping to tackle one of the most harmful forms of marine life.
05:42Back in France, at the historic port of Socoa, Professor Grégoire's team is testing new uses for oyster shells.
06:03Maintenance crews are reinforcing harbour walls with a low-carbon mortar, made from processed shells and less cement.
06:12The mix needs refining for better usability, but lab tests show it's strong enough to withstand harsh conditions.
06:19Behind this 17th century fort, the team has placed dozens of small concrete blocks,
06:48made with oyster shells, made with oyster shells.
06:51The experiment looks at how sea life responds to these materials.
06:56As the tides come and go, algae and shellfish settle on the blocks,
07:01turning old shells into new habitats.
07:05This could offer a simple, sustainable way to create artificial reefs and support marine life.
07:14If there is an important colonisation on the new habitats,
07:18the same, even better, than on the natural substrate,
07:22then we can conclude that there may be a advantage to use this stone.
07:26It's like a mini-laboratory in full air.
07:30Such artificial reefs could do more than support marine life.
07:35Structures made from oyster-based concrete could help protect coastlines from rising seas and erosion.
07:43By repurposing marine industry waste, European researchers are turning today's discards into tomorrow's building blocks.
07:53Transcription by ESO, translated by —