‘Green gold’: Could we feed the world sustainably with microalgae?

Microalgae are massively abundant in our seas and act as biomass factories, by harnessing their power we may be able to alleviate food-security issues around the world, writes Carole Anne Llewellyn

The food of the future? (Getty/iStock)

As a young child in the mid-1960s, my days were spent living an idyllic rural life on a dairy farm in the village of Lewdown in the heart of Devon. I recall many happy days exploring the glorious countryside, living a life in balance with nature and the environment – or at least, that’s how it felt.

But I also remember the ever-present slurry pit full of manure down at the end of our cowshed. It wasn’t fenced off, and my mum would remind me on regular occasions that to stray too close could mean death by drowning in what was, in essence, an enormous vat of smelly cow pats. As a five-year-old, I stayed well clear.

What we didn’t know then was that this pit of farm manure posed not only a hazard to me, but to our environment. Manure, which is often returned to the land as a nutrient fertiliser without consideration of its wider impacts, releases greenhouse gases including methane, carbon dioxide and nitrous oxide, and other harmful nitrogenous gases such as ammonia. It can also lead to nitrogen-rich run-off into water courses, polluting rivers, lakes and coastlines – with knock-on effects on fish mortality and tourism.