India taps seaweed farming in its green battle

RAMESWARAM (India) • Draped in a colourful sari and shirt, Ms Lakshmi Murgesan dives into the azure waters off India's southern coast to collect seaweed, which is being hailed by scientists as a miracle crop that absorbs more carbon dioxide than trees.

India is the world's third largest carbon polluter, behind China and the United States, and has yet to set a target date for its emissions to reach net zero.

But the authorities are looking into how seaweed farming could help reduce the impact of greenhouse gas emissions, reverse ocean acidification and improve the marine environment, as well as provide a sustainable livelihood for marginalised coastal communities.

"I am doing this for my children... It requires a lot of hard work, but I am able to earn good profits from about four months of work," said Ms Lakshmi, who makes 20,000 rupees (S$360) each month farming the fibrous macroalgae.

"I would not have been able to educate my children but after doing this, I could send my children to college," she added, smiling as she emerged from the waters in Rameswaram, in the southern state of Tamil Nadu.

Dr M. Ganesan, a government marine scientist, said seaweed provides a possible way forward as coastal habitats and wetlands absorb five times more carbon than terrestrial forests. "It is a miracle crop in many ways - it is eco-friendly, it doesn't use land or fresh water, it absorbs carbon dioxide dissolved in water during photosynthesis and oxygenates the entire marine ecosystem," he told Agence France-Presse.

India, which has an 8,000km coastline, is now aiming to boost production from the current 30,000 tonnes to more than one million tonnes each year by 2025.

Globally, seaweed production was worth around US$12 billion (S$16 billion) in 2019 and is expected to grow to US$26 billion by 2025, with China and Indonesia having 80 per cent market share.

Ms Lakshmi is part of a team of women who work together to cultivate fronds of seaweed on bamboo rafts, before harvesting and drying them. The tropical waters of Tamil Nadu form an ideal environment - with one raft yielding up to 200kg in around 45 days.

The product is then sent for sale in markets nationwide as well as the US and Australia through AquAgri, a private company that promotes algal cultivation in India.

Popular in East and South-east Asian cuisine, seaweed is also used in medicine, cosmetics, bio-fertiliser and bio-fuel. The marine plant does not require fertiliser, fresh water or pesticides. Kelp, one of the most commonly farmed types, grows at a rate of 61cm a day.

They absorb an estimated 173 million tonnes of carbon each year - the same annual emissions as New York State, according to a 2016 paper in Nature Geosciences.

However, scientists say there can be downsides to farming it.

"Overharvesting seaweed has its drawbacks because it forms the food for many reef-dwelling creatures like sea urchins and reef fish," said marine biologist Naveen Namboothri, from Dakshin Foundation, adding that extraction could disturb the reef.

AGENCE FRANCE-PRESSE