Seaweed farming might hold the key to massive improvements in carbon sequestration, biodiversity loss and food security say Queensland researchers.
They investigated a red seaweed genus known as Asparagopsis for its potential as a source of dietary energy for humans, a supplement for livestock thanks to its potent ability to reduce methane, a constituent in biofuels for the transport industry, and in combination.
They found up to 2.6 billion tonnes of greenhouse gas emission could be diverted as a result of introducing seaweed farming, with Australian and Indonesian economic waters providing a viable location among all possible areas of production.
Notably, if seaweed was to take up just one tenth of everyone’s diet, 100 million hectares of on-land production could be avoided – about the combined land area of New South Wales and Victoria.
University of Queensland researcher Scott Spillas says a cultivated seaweed industry could provide a viable economic and sustainability-focussed opportunity for western nations to consider as part of their efforts to combat carbon emissions and food shortages.
Some countries – particularly East Asian nations like China, Japan and Korea – already cultivate dietary seaweed. Korean diets are estimated to consist of two percent of seaweed alone.
Even introducing that amount of dietary seaweed globally could make a substantial dent in carbon emissions from agriculture.
“The ocean is really big, it’s most of the planet’s surface, so there’s a lot of space there. We don’t really use it,” Spillas says.
Spillas’ research is built on available information, but says developing knowledge of where seaweed species can best grow would enhance the potential of a new industry.
Seaweed farming also promises opportunities for habitat regeneration as well as restoring ecosystem balance due to nutrient overload in aquatic and marine environments.
But although growing a tonne of biomass under the sea would divert the possible loss of biodiversity and negative land use impacts of doing so across a hectare of land, Spillas also warns such a move would need to be properly considered.
That’s to prevent potentially diverting environmental damage from land to sea.
“We need to be careful when we have this conversation, because the ocean is also under threat from a variety of sources,” he says.
“And so we definitely don’t want to be saying we should just go out and start pillaging the ocean to start growing seaweed farms.
“But if we want to create an extra tonne of biomass, potentially growing it in the sea would have lesser impacts when it comes to global sustainability.”