Did you know you use products containing seaweed every day? You can find it in toothpaste, cosmetics, beer, ice cream and even paints. On a broader industrial level, it is used as a green fuel, in fertiliser and animal feed all with little harm to the environment, or so it is believed.
So while your tucking into your miso soup or Nori wrapped sushi, give a little thought to how this ‘weed of the sea’ has ended up on your plate and the farming processes behind it.
The majority of seaweed harvesting in the UK is still gathered by hand at low tide but there are an increasing number of seaweed farms being established around the British coast. These farms are a very basic construction being a floating frame, with ropes placed in parallel across the frame in 3 meter intervals. The mooring system is simple as well, and very similar to the cage mooring systems used in fish farming.
All sounds ecologically fantastic until you delve a little deeper into the material make up of the ropes in question, polypropylene. With the world becoming focused on reducing plastic pollution within our oceans, it’s no surprise that even this most humble of industries is looking to change its farming practices over the coming years.
Rope has been fundamental to human development for millennia. The first evidence of rope goes back some 50,000 years, with a fragment of three-ply cord discovered at a Neanderthal site but its use probably goes back much, much further.
It is likely that the earliest “ropes” were naturally occurring lengths of plant fibre, such as vines, followed soon by the first attempts at twisting and braiding these strands together to form the first proper ropes in the modern sense of the word.
The ancient Egyptians used rope made of water reed fibres and these ropes, pulled by thousands of workers, allowed the Egyptians to move the heavy stones required to build their monuments.
Starting from approximately 2800 BC, rope made of hemp fibres was in use in China and became the predominantly used variety up to almost the present day. Today, some rope is still made from natural fibres such as coir and sisal but the now dominance of synthetic fibres such as nylon and polypropylene have become increasingly popular since the 1950s.
And there’s the rub, almost literally. Plastic rope is being washed up on coastlines and rubbing against rocks, resulting in them becoming coated in a hard plastic, or plasticrust, which could cause wider issues by entering the marine food chain. A similar effect can result by the hauling of heavy nets back onboard fishing vessels, the resulting abrasion releasing millions of micro plastic fragments into the sea. And then there’s simple degradation, with plastic taking and average of 20 years to breakdown, with some taking much, much longer.
But an answer could be at hand.
Plastic or Wool…………….
Kate Drury is a fourth generation sheep farmer and sits on the Board of British Wool, so knows a thing or two about the overall benefits of this material. Following a meeting between the Royal Agricultural University and a Seaweed Agent from the Southern Hemisphere, she was brought in to discuss the possibility of using wool as a substrate rope onto which seaweed could grow.
“I was initially asked to undertake research into this idea, which has since developed into a fully funded Phd researching wool rope in a marine environment,” said Kate.
“This is slightly unusual as this type of funding usual goes to disciplines such as high-tech or medicine, which probably shows the importance the RAU is placing on this development.”
“Seaweed has many uses, including fertilizers, animal feeds, human consumption and even cosmetics, with the driver in this instance being cattle feed. It also negates carbon and nitrogen and provides an ecosystem and wool rope can help that happen sustainably.
“Seaweed aqua-culture in the UK is only emerging, although of huge interest. The UK Marine Management Organization are struggling with its application and consequences of using plastic rope, making their licenses extremely expensive – the cost of which is significantly cheaper using a natural fibre rope”
The first natural fibre to be considered by the RAU was hemp. As the seaweed is to be grown in UK waters, regulations state that any rope produced must source its materials from the UK and be a natural fibre, which was thought to be unfeasible. The issue here is hemp is not commercially produced in this country, hence the alternative idea of using wool was born.
Initially the research team left wool examples in a Scottish loch for eight months from which it was found the seaweed had grown well and had also attracted other marine creatures such as isopods, which is a type of crustacean.
“The rope is also completely biodegradable, so if it’s lost and left where it shouldn’t be it’s not as aggressive in the environment as the plastic variety. Basically, as it degrades it breaks down into its original components, which plastic does not.”
“The product is very durable and flexible, with it’s broad variety of uses meaning very little is wasted, as well as being renewable and sustainable with antibacterial properties.”
One company that Kate now works with grow seaweed for bio-ethanol and fertilizer and for both these products there is no need to separate the wool rope from the seaweed, which means they will spend less time out at sea by gathering the rope rather than harvesting the seaweed. Everything would then go into the bio-ethanol boilers.”
“This level of production will create an annual demand for wool, which have the added benefit of providing a new source of income for sheep farmers.”
Research and Development
At this point it was decided to set up a private company to move development forward, Sustainable Rope Ltd, through which trials of the rope were commissioned as part of its overall R&D strategy. The company is now almost two years old and is already the recipient of the Innovation in Wool and Women in Innovation Awards.
“We felt this was the best way forward as there are no commercial manufacturers, with only a limited amount produced for the likes of the interior design market and dog leads!”
“The benefits of this approach initially is to further the research requirements. The data obtained will help establish the best place of manufacture and other variables such as sufficient wool supply, potential of commercial companies switching production methods/materials and materials testing, where the non commercial help of Tinius Olsen is proving indispensable as there’s a huge amount to do!”
“It will take two years to provide data that will enable commercial producers to switch, which will take time as both types of rope are obviously engineered differently – you can’t just throw out polypropylene and change to wool rope, it’s much more complex as both are engineered completely differently.”
The materials testing undertaken at Tinius Olsen’s in-house laboratory will establish the tensile strength of the rope under Standards such as ASTM D-6268.
“It’s great to have existing international standards available as a starting point. With the testing of rope you have two very important definitions, tensile strength and working load. The former gives the average strength of new rope under laboratory conditions, which is then divided by a factor that more accurately reflects the maximum load the rope will stand.”
“As this is a new rope material we are basically starting from scratch, especially as we’re still studying the effects of degradation and damage within a marine environment.”
“Then there’s working load, which for most types of rope is between 15% to 25% of the tensile strength. When you tie a knot in a rope it effectively cuts the tensile strength in half, although this can vary between knot types. For instance, a figure 8 knot reduces the tensile strength by approximately 35%.”
“To add to this, Tinius Olsen had to design and engineer new grips before any testing could be undertaken, which highlights just how new this product is.” continued Kate.
Samples of rope were harvested after 90, 180 and 270 days soaking in land tanks full of reef salt water. Breaking strain results were then taken from widths between 6mm to 14mm in two ranges of yarn as they take separate routes in the wool supply chain.
“The data is being compared with hemp, although if the wool rope sits within a comfortable performance window compared to manila or sisal rope material then that’s fine. It is now virtually impossible to get the raw materials for both these types of rope and cost a fortune to ship to the Northern Hemisphere, so the benefits of wool are potentially huge.”
“It is also expected for extensive testing to open up opportunities aside from mariculture, including land based permaculture. In fact there are four universities currently setting up ecosystem renewal based trials with the rope.”
However, Kate is keen to stress that this new eco friendly rope is not targeting global fishing, although its obvious ecological benefits could bring broad ranging changes to the industry into the future.
“We are concentrating firmly on the seaweed sector at this time although there are developments at governmental level that could expand the ropes use moving forward.”
One driver is the Global Ocean Alliance, which is a 73 country alliance led by the UK Government championing ambitious ocean action within the Convention on Biological Diversity. Its aims include creating a global network of marine protected areas, safeguarding the health and biodiversity of the world’s oceans and help to combat the effects of climate change.
This includes the ocean targets set by 30by30, a worldwide initiative for governments launched by the High Ambition Coalition and Nature and People in 2020, which aims to protect at least 30% of the global ocean by 2030.
“The ocean covers 70% of the world’s surface with at present just 2.7% of it lying within a protected zone. As such, 30by30 is calling on governments and world leaders to urgently increase the level of protection for our increasingly fragile marine environments.”
“The pre tax loading of plastics following the adoption of 30by30 will have a huge impact on marine based industries, including the seaweed industry as we know it, which will obviously include the production of plastic rope moving forward.”
So What Next?
Interest in this wool rope application has grown exponentially as word has spread of its development and potential benefits to both the environment and fishing industry based economy.
Production is of course dependent on the data acquired from the extensive materials testing currently well underway. There are already 860 samples being tested during the second trial of the rope this year, which Tinius Olsen are again supporting.
The results of this and broader research data will establish the best place of manufacture and other variables such as sufficient wool supply and the potential of commercial companies switching production methods/materials.
“Polypropylene rope lasts, on average, ten years whereas a wool rope lasts a year in comparison. At present there is no global agreement on rope management in terms of its material make up and usage but, I would hope, the results of the extensive R&D we’re providing will help influence this vital development.”
It’s going to be a very interesting few years ahead, especially if you’re a sheep……..