The scientific wonders of seaweed

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My childhood memories of seaweed involve trips to the seaside and being washed up in a pool of slimy seaweed that felt disgusting. It didn't feel particularly useful at the time and it always felt a shame to waste the image of a nice seaside coast. In my adult years, I learned to enjoy seaweed when it was wrapped nicely around a sushi roll and I learnt to appreciate that it could be a delicacy.

There are many health benefits to eating some forms of seaweed and in some Eastern cultures, it can be a prevalent part of the diet. Some are classed as superfoods due to their high minerals and nutrient content. In Western cultures, seaweed is not so obviously popular although many do end up ingesting it as it can make a popular food additive.

In more recent time, researchers have found ways of creating a biodegradable polymer that can be used as a plastics that degrade into non-toxic waste that can be recycled into organic waste. The advantage is that it grows saltwater and therefore doesn't fill our limited fresh water supply unnecessarily. It could one day replace a lot of petroleum-based plastic packaging.

A blue paper by Ocean Panel now discusses that 364 million tonnes of animal protein could be provided by the oceans that is more than the two-thirds of the amount needed to feed the world's population. Seaweed would be the crucial enabler to make this happen by quickly providing a source of nutrients for sea life to feed on and thus rebuilding the depleted ocean food source. Artificial habitats can easily be created with low maintenance costs as sea farming of seaweed is much easier than landfarming. It only requires weighted lines seeded with seaweed to be suspended a few metres below the surface. These can quickly be retrieved or moved and they do not require artificial fertilisers.

The seaweed can also balance the ocean and prevent harmful algae from growing. It can therefore be used next to other farms where mussels and oysters are grown and it will balance the ecosystem. To this extent, a 2019 study, estimated that 77 countries could be fed by developing 48 million square kilometres to seaweed farming.

Seaweed can also help in the reduction in the greenhouse gas methane. Research shows that feeding some red seaweed in the diet of cows was able to reduce methane emissions by 67%. Blue Ocean Barns, a California based farm, is not trying to get this approach approved in the US.

Perhaps one of the greatest benefits of seaweed to mankind may be the possibility of carbon capture as reported by the New Scientist. The idea being proposed by Tim Flannery from the Australian Museum in Sydney, is that large seaweed-based farms can be created and the seaweed captures CO2 from the atmosphere. It can then be harvested and big bundles can be sunk into the ocean depths. A 2012 study estimated that seaweed forests covering 9% of the oceans could reduce CO2 to pre-industrial levels.

It seems a very lofty ambition and the New Scientist article does point to some potential side effects. However, whether it is plastic alternatives, helping produce more sea-based food, reducing methane emissions or helping capture carbon, the wonders of seaweed are something we are likely to hear more about in the coming years. Personally, I now see seaweed in a new light and not just that disgusting slimy plant that ruined my youthful seaside experiences.