Solutions from the Sea: Can coastal communities benefit from the world’s growing seaweed industry?

Rameswaram is a small village in the South of India that has a very unique connection with the sea. Situated here is the countries’ only successful seaweed extraction enterprise, run by women. Every day at dawn, the women make their way to the bay and take a boat out into the waters of the Gulf of Mannar. With basic masks, and makeshift fins, they scour the ocean floor, collecting clumps of algae that will earn them their livelihood. This local industry runs on the global demand for seaweed as one of the most effective gelling and stabilizing agents available. Seaweed extract is used in everyday cosmetics, drugs to treat tuberculosis and cancer and in a growing number of food items. Seaweed farming however, has the potential to do so much more.

For starters, it could feed the world and help reverse climate change.

gulf of mannar
Seaweed divers of the Gulf of Mannar – Image credit – Shilpi Sharma

Covering 9% of the world’s ocean surface (with seaweed), could produce sufficient biomethane to replace all of today’s needs in fossil fuel energy, while removing 53 billion tons of CO2 per year from the atmosphere, restoring pre-industrial levels. This amount of biomass could also increase sustainable fish production to potentially provide 200 kg/yr/person for 10 billion people” claims Antoine de Ramon N‘Yeurt and his team of scientists in their 2012 paper on Ocean Afforestation.

Although 9% of the ocean’s surface is an area four times that of Australia, many scientists believe large – scale seaweed farms could be a viable solution for mitigating climate change impacts and ensuring global food security. Tim Flannery, a climate specialist and Co-Founder of the Climate Commission is one such seaweed enthusiast. In his latest article in the Conversation he describes the potential of seaweed farming in feeding and fueling the world. With its ability to grow almost anywhere from the temperate regions to the tropics, he claims seaweed is also a viable biofuel as well as natural fertilizer, growing thirty times faster than any terrestrial plant source. Seaweed production at this scale could also help reduce ocean acidification by increasing local oceanic pH levels and oxidizing waters.

Such large- scale seaweed farming projects though achievable, are also highly controversial. Producing seaweed at this scale is bound to have multiple environmental implications, one of the biggest being the use of invasive species that take over coral reefs, competing for light and space. Large scale seaweed cultivation in the open ocean would also require huge inputs of nutrients which could in turn cause large algal blooms and subsequent dead zones.

Seaweed farming could still be a credible solution to climate change and growing food insecurity if carried out through a community based model with strict scientific guidelines. Its ability to grow along coastlines across the globe, act as carbon sinks and support local biodiversity when planned at a regional level could help boost local economies and help traditional fishing communities retain their maritime ties.

A coastal village bordering the Gulf of Mannar – Image credit – Gabriella D’Cruz 

With plummeting fish stocks and bleaching reefs, the ocean no longer offers the same incentives to coastal communities. Thousands of such communities live along coasts in developing nations and are now moving to urban areas, severing their bonds with the sea.

The women seaweed farmers of South India face a similar fate. Having spent decades harvesting seaweed with a minimal increment in their income, they aren’t optimistic about the future. A lack of market based incentives coupled with tough working conditions have forced the younger generation of women to seek work elsewhere. While the monetary benefits of seaweed harvesting have put their kids through school and given them a better stand in a patriarchal society, the women seem to have lost hope in the industries’ ability to support them for much longer. Having refused to teach their children the art of diving for seaweed, many have plans of leaving their hometown for the city.

If seaweed cultivation is to be a viable solution in mitigating climate change impacts and maintaining global food security, it must be developed with scientific understanding, through market based incentives and in close partnership with vulnerable communities that live by the sea.

seaweed lady 2
A seaweed diver prepares for the last dive of the day – Image credit – Rita Banerji
  1. Duarte, C. M. et al. (2017) ‘Can Seaweed Farming Play a Role in Climate Change Mitigation and Adaptation?’, Frontiers in Marine Science, 4, p. 100. doi: 10.3389/fmars.2017.00100
  2. N’Yeurt, A. D. R. et al. (2012) ‘Negative carbon via ocean afforestation’, Process Safety and Environmental Protection, 90(6), pp. 467–474. doi: 10.1016/j.psep.2012.10.008.
  3. Flannery, T., 2017. The Conversation. [Online]
    Available at:
  4. FAO., 2016. The State of World Fisheries and Aquaculture 2016. Contributing to food security and nutrition for all.. [Online]
    Available at:
  5. Flannery, T., 2015. The Guardian. [Online]
    Available at:

Featured Image – Seaweed Forests – Image credit – Sunken Seaweed



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