Algae- ‘Green Gold’- or Something More Valuable?

by Becca Payling

World Algae Day falls on Oct 12th each year, but with algae’s growing importance in society, it is likely to be an area of great interest, development, and research for many years to come.

Once only associated with eutrophication (the green sludge on the surface of water bodies), algae are now the material darling of the 21st century. From their incorporation into trainers, bioplastics, dyes, fuel, and now even touted as being able to reduce methane emissions from ruminants by up to 99%, it seems that there is nothing that algae can’t do.

Algae are often split into two categories: microalgae and macroalgae. Microalgae include blue-green algae (cyanobacteria- one of the oldest life forms in Earth history) and diatoms, whereas macroalgae include kelp, seaweed, and red algae, including calcifying algae that make up corals. Just like their physiological diversity, all species of algae provide a wealth of uses and services- often as the source of energy within the marine and intertidal ecosystems in which they bloom. As part of my breakfast each morning I have a spirulina tablet- with an abundance of B12, omega-3, and other vitamins and minerals like calcium- an ideal vegan supplement in a plant-based-returning world.

Spirulina has a rich indigenous history, with the Mexica people developing farming techniques, recipes, and rituals surrounding these algae before colonisation that is now being reclaimed (DeRenzo, 2021 for BBC Ancient Eats), and there are numerous ethnobotany studies between First Nation or Sicilian communities and red algae – showcasing uses spanning from food, medicine, mental health, and even fibre, highlighting their vitality in local communities and culture (Turner, 2003; La Rosa et al., 2021). Vertical farms are being installed globally for spirulina, a  physical representation of the skyward trend in consumer craze the algae ‘superfood’ has seen, whilst below sea level, seaweeds and zooxanthellae algae that live symbiotically with corals reefs are a steady storm buffer (James et al., 2019) as climate change brings more extreme weather events. Time is precious in the midst of the climate crisis, and algae acting as a low-carbon material alternative, and their ability to mitigate climate effects, buy us some.

“With attention to the energy sector as the most game-changing industry to foster innovative solutions for climate change mitigation, algal lipid use for biofuel is less controversial than other biofuels.”

For environmentalists, it is a fact well known that there are more microplastics in the sea than there are stars in the galaxy. Whilst there are no estimates for the total number of algae on Earth, (only that there are up to 1 million species), the total biomass is 0.5 Gt C (gigatonnes of carbon) (Bar-On & Milo, 2019), far outweighing estimates of total microplastic mass. Biology: 1, Humans: 0, happily and for now. Whilst winning the weight game on Earth, certain microalgae also can break down the worst synthetic plastic offenders such as LDPE and PET so they can no longer accumulate in organism tissue (Kaur & Redderson, 2022).

Algae, particularly green algae, are also effective adsorbents of heavy metals such as cadmium and nickel found in wastewater, making them an effective remediate during mine clean-ups that will probably be used more and more in the future as critical metal extraction with a rocket for renewable energy infrastructure. Excitingly, whilst algae can also break down plastics, they are also the backbone for a new wave of bioplastics (and foams) for packaging, clothing, single-use plastics, and footwear, as other bio-based plastics such as corn require intensive land use in an age of growing food insecurity (Kaur & Redderson, 2022), whereas water has a depth dimension to allow greater cultivation of algae. However, care must be taken when creating these plastics, as the limited ability of some types to compost, and the intensive processing needed to recycle or repurpose bioplastics, means that integrating this material into a circular economy requires careful planning (Rosenboom et al., 2022). 

“Seaweeds can reduce pollution levels and even grow better if grown alongside fish farms”

The process of dyeing using algae to replace synthetic, non-degradable, and often toxic dyes used in clothing, has been successful so far at inspiring creative circular innovation, particularly where waste sidestreams of algae and seaweed are utilised, and inadvertently improving wearer health through their antimicrobial properties (Mona et al., 2019). Here the joy of creating something beautiful has cultivated a whole other range of- what could be seen as more functional- benefits.

With attention to the energy sector as the most game-changing industry to foster innovative solutions for climate change mitigation, algal lipid use for biofuel is less controversial than other biomass sources, and numerous sources highlight its greater efficiency than other biofuels. With the current interest in developing widespread use in jet fuel, algae may be useful in the green energy transition, as well as powering aquaculture and pastoral feeds. These cases highlight algae as a creator and destroyer of various industries in the Anthropocene, but they also forge a respectful carbon sink, and are collectively and quietly responsible for 70% of oxygen in the atmosphere, making them the real lungs of the Earth. 

Seaweed such as kelp and the secondary school exam question classic- bladderwrack- are the most familiar forms of algae. It’s hard not to see what is now seen as ‘bougie’ seaweed food products and insect bite creams in Holland Barrett, along with varying moisturisers and other cosmetics in TK Maxx and La Mer adverts in the airport hailing the organisms’ unrivalled moisturising property. Due to Ireland’s affluent waters, 501 species thrive in the Irish Sea and Atlantic Ocean, with folklore extending into use as fuel and in local crafts (Cork Nature Network, 2021).

“In the climate crisis, should we be only favouring ‘useful’ algae, or is it better to adopt an ecocentric view as all algae being intrinsically worthy and explore our interrelationships?”

It is perhaps also unsurprising that cutting-edge research is being conducted into Atlantic kelp in Dr. O’Connor’s Beyond Biofuel research group in Trinity, testing new cultivation methods for seaweed for a ‘Blue Carbon Strategy’, mitigating oceanic climate change, as well as for medicine and biofuel in Ireland’s growing bioeconomy. Frank Spellman, a second-year Ph.D. candidate focuses on the biodiversity aspects of kelp-growing methods of the species dabberlocks, sugar kelp, and oarweed to close the knowledge gaps of Irish kelp forest ecology. This focus on ecosystem health is particularly important as demand for algae grows, with an 8% p.a. increase in kelp farming predominantly in Asia. He writes about his research and potential for kelp farming in Ireland: 

“What appealed to me about kelp farming initially was how clean it was compared to other aquaculture like fish farms. The kelp is put out as babies on a rope and it just grows. No polluting fertiliser, feed, or waste is caused by the likes of fish farming. Seaweeds can reduce pollution levels and even grow better if grown alongside fish farms. Unfortunately, change comes slowly. Many in coastal communities are sceptical of the potential benefits and afraid of how they may change the look of the coastline. The industry also has a lot of hurdles to jump before it can become profitable in Ireland from both financial and legislative points.  With kelp forests being one of our most important habitats for marine life in Ireland, increased demand for seaweeds worldwide, and the continual decline in marine life in Irish water, I hope my research will help develop a young Irish seaweed farming industry that provides long-term, profitable and environmentally sustainable jobs for coastal communities around Ireland.”

Simon Benson, a Ph.D. candidate also on the Beyond Biofuel Project, and Fossil Free TCD Lead Campaigner explores the genetic diversity and biotic interrelations between the Irish brown seaweeds oarweed, cuvie, and Atlantic sugar kelp, in a quest to propose how biodiversity can proliferate in line with diversifying agriculture and staying in line with climate targets. He aspires to “be able to promote a sustainable and biodiverse seaweed bioeconomy focused on producing a range of specialised alginate hydrogels for biomedical and research applications.”

He adds “An Irish algal renaissance would undoubtedly make our agricultural sector more resilient as a whole, however, we should be careful to not just repeat the same extractive, polluting, and habitat-destroying practices that have dominated our terrestrial landscapes for approximately the last century.”

In human-nature discourse, there is a propensity to discuss nature with what benefits it gives to humans, in anthropocentric terms, exemplified in the UN’s ecosystem services. Algae can provide regulatory, provisioning, and supporting services, in the case of kelp farming, for minimising water contamination, for fostering biodiverse marine healthy habitats, and for product application respectively as Frank discussed. Whilst it can be argued that the following feature can be placed under ‘cultural services’, some algae- dinoflagellates called Noctiluca scintillans (sea sparkles)- are bioluminescent as a byproduct of a chemical reaction. This lustrous blue-green glow attracts people to beaches far and wide across the Americas, East Asia, and Oceania, providing touristic revenue to the communities in these regions.

“Algae are looking to be our lifeline in the future, not only in their capacity to hold CO₂ like our own haemoglobin, but in their ability to transform our diets, the many fabrics in existence, and potentially the energy that society runs on”

In the climate crisis, should we be only favouring ‘useful’ algae, or is it better to adopt an ecocentric view as all algae being intrinsically worthy and explore our interrelationships? Assigning varying values to nature is inevitable in a capitalist society, but amid a biodiversity crisis, the sixth mass extinction, it’s important to protect all our algae, or the cost will be high.

An entrepreneur or economist may nickname algae ‘green gold’. After all, algae are becoming high in worth, and like ‘black gold’ coal, algae have the opportunity to revolutionise society- and the carbon in the atmosphere and ocean. Perhaps even more so since nature accelerates most abiotic processes on Earth. However, algae are living and are connected, to the atmospheric composition, and lives and our livelihoods, so it may be more appropriate to term algae ‘green blood’. The members of the polyphyletic group Algae are looking to be our lifeline in the future, not only in their capacity to hold CO₂ like our own haemoglobin, but in their ability to transform our diets, the many fabrics in existence, and potentially the energy that society runs on. But maybe most importantly, in a worn-out and rapidly changing world, algae are healing, at an organism scale and at the planetary scale.

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