When we think of kelp, we conjure up images of magical underwater forests. Recent research, however, suggests that in addition to creating beautiful habitats, macroalgae such as kelp play a large role reducing the effects of global warming. Kelp has an incredibly fast growth rate (up to two feet per day) and exports a large portion of its biomass out into the deep sea, allowing kelp to permanently remove carbon dioxide from the atmosphere. Removing carbon dioxide from the atmosphere will play a necessary role in preventing rising temperatures and future climate catastrophe.
An increasing body of research is documenting the potential of seaweed farming to counter climate change as deforestation decimates rainforests and other crucial carbon sinks. Fast-growing oceanic jungles of kelp and other macroalgae are highly efficient at storing carbon. Seaweed also ameliorates acidification, deoxygenation, and other marine impacts of global warming that threaten the biodiversity of the seas and the source of food and livelihoods for hundreds of millions of people.
Seaweed is currently grown on a small scale for use in food, medicines, and beauty products. The scientists, however, propose the establishment of industrial-size farms to grow seaweed to maturity, harvest it, and then sink it in the deep ocean where the captured carbon dioxide would be entombed for hundreds to thousands of years.
They found that raising macroalgae in just 0.001 percent of seaweed-growing waters worldwide and then burying it at sea could offset the entire carbon emissions of the rapidly growing global aquaculture industry, which supplies half of the world’s seafood. Altogether, 18.5 million square miles of the ocean is suitable for seaweed cultivation, the study concluded.
Getting the international carbon credit bean counters to accept seaweed as a legitimate source of greenhouse gas reduction is one of the bigger challenges.
In a new study, researchers at the Norwegian Institute for Water Research (NIVA) have tested the effect of increased CO2 levels on one of Norway’s most common kelp species, the sugar kelp (Saccharina latissima).
– The on-going increase in CO2 in the atmosphere, and the following reduction of pH in seas and oceans, are pronounced and have been pointed out as the second most dramatic factor influencing ocean life after increasing water temperature, says Kasper Hancke, marine biologist and senior researcher at NIVA.
– However, kelp and seaweeds take up CO2 as part of their photosynthesis and use the carbon, in combination with sunlight and nutrients, to grow – just like plants on land. This implies that an increase of CO2 in the ocean theoretically could stimulate higher growth of kelp and seaweeds, Hancke explains.
To use seaweed to tackle climate change, policymakers need to develop more policies to motivate people to farm seaweed and expand it. As consumers, we can spread these messages and start turning seaweed into everyday food.
Despite a long coastline suitable for seaweed cultivation, the Lofoten Islands has almost no offshore aquaculture operations of seaweed. The exception is Lofoten Blue Harvest AS on the inner side of East Lofoten. China and other Asian nations that produce most of the world’s farmed seaweed are expected to take the lead in establishing macroalgae as a source of “blue carbon.”