We’ve all heard of nori, but both the volume and variety of algae and seaweed available on the market go far beyond the classic sushi variety. Now used as foodstuffs, in supplements and nutraceuticals, as livestock feed, in medicine and even in fertilisers, both macroalgae – i.e. the macroscopic species known commonly as seaweed – and microalgae, the microscopic species, are becoming more and more popular.

There is also a vast amount of research being carried out into seaweed, with hopes rising that these seemingly simple organisms could play a key role in saving the environment. In short, the potential applications of seaweed are increasing in number by the day, to the extent that the commercial macroalgae market is expected to be worth over $87 million by 2014.

Seaweed and pollution in the atmosphere

Global warming is happening too fast for our ecosystems to repair themselves or adapt naturally, leaving our environment under an unprecedented level of stress. Think of the melting of the ice caps, for example, or ocean acidification and the progressive disappearance of entire habitats. It’s undeniable that many human activities responsible for generating greenhouse gas emissions are among the leading causes of climate change.

Yet against this backdrop, the varied family of marine organisms known as algae is proving that it can play a key role in providing a quick fix for the situation, thanks to its unique physiology.

CO₂ catchers

Seaweed uses the process of photosynthesis, whereby it emits oxygen and transforms sunlight into chemical energy. It’s exactly the same process used by plants, but in this case there is no need to use up large amounts of land for cultivation. Seaweed also absorbs CO₂, the main greenhouse gas produced by human activity, and have the potential to significantly reduce ocean acidification, another consequence of the increased levels of CO₂ in the atmosphere and the cause of the degradation of coral reefs and other marine habitats. The most efficient species in terms of absorption are kelp and other laminariales, which are cultivated abundantly in China, Korea and Japan. And if the expansion of aquaculture is developed according to sustainable models, scientists believe that it could help to remove billions of tonnes of CO₂ from our atmosphere.

Water filters

It’s not just about CO₂, however. Seaweed is also proving useful as part of efforts to purify polluted waters generated by waste substances, targeting excesses of nitrogen and phosphorous deriving from waste water used as fertilisers in agriculture. Once these have been gathered and dried, the seaweed – now with a high density of these substances – can be reused as agricultural fertiliser.

Studies are also being carried out into seaweed’s capacity for absorbing toxic metals such as lead, chrome, iron, copper and manganese and industrial waste such as paint.

Green fuel

One of the most interesting uses of micro and macroalgae – albeit still in the experimental stage – is in the production of biofuels, which provide a green alternative to classic fossil fuels. In this case, the quantity of CO₂ produced through fuel burning is equal (or almost equal) to the amount removed from the atmosphere from the seaweed, meaning the system can be considered CO₂ neutral. Moreover, it’s a far cheaper option than extracting fossil fuels.

This type of biofuel could be used by all forms of transport, from regular cars to heavy vehicles, ships and even aeroplanes, where the clamour for progress is particularly strong given the urgent need to reduce the environmental impact of air travel.

Once the biofuel has been produced using the seaweed, the solid remains are collected and dried, leaving nothing more than a mix of carbohydrates and protein. Experts believe this could be a good alternative to soy in livestock feed for cows, pigs and poultry, providing an environmentally sustainable solution that would allow humans to cut down on the amount of land used to cultivate crops destined for livestock consumption.

Plastic replacement

Research is also being undertaking to investigate seaweed’s potential for use in natural packaging for products. It is though that this type of packaging would be less harmful for the environment than plastic – and investigations are even underway to produce fully edible packaging.

One British startup is working to produce an seaweed-based alternative to conventional classic bottles for water and other liquids. The product is a soft, transparent membrane created by using a number of components from these organisms and can be used as bags for storing drinks. Incredible, the bag can then be eaten!