Kelp Wanted!
By Alyson Liu
Photo by Matt Cosby, courtesy of Atlantic Sea Farms
In case you haven’t heard, the human population is skyrocketing, and so are carbon dioxide emissions. The good news is, vast areas of ocean water are available to grow mass amounts of what could be a potential climate change superhero: kelp. This macroalgae’s potential to help take in carbon dioxide from the atmosphere is heavily based upon its speedy growth rate. A protist, such as kelp, is defined as a eukaryote that is not an animal, plant, nor fungi. Although algae is not a plant, it contains the chlorophyll-a pigment that allows it to photosynthesize by using carbon dioxide, nutrients, and water to produce sugars and oxygen. Giant kelp can grow 11-24 inches every day and has a relatively short life cycle compared to trees and can therefore consume carbon more efficiently. When algae dies, it sinks to the bottom of the ocean, where it can remain for thousands of years or even be sequestered by calcifying organisms such as shellfish. As one of the fastest growing organisms on Earth, it is estimated that seaweed sequesters approximately 200 million tons of carbon dioxide per year. Another advantage to banking on algae farms is that no freshwater usage is required, and neither is fertilizer or weeding.
Algae farms have many other hidden talents up their sleeves. By 2050, the human population will be so large that we will need to increase food production by 70%. Algae manufacturers are discovering how to create oils, foods, and supplements in a sustainable manner, which could serve as a vital source of food in times of future scarcity and even provide us with 10% of our food.
Better yet, algae can be made into biodegradable plastics and fibers. Algae polymers replace the synthetic petroleum fibers that are typically used to manufacture anything from foam, to bottles, to surfboards, to toothpaste, to shoes, and even ice cream. All the while, carbon dioxide is being removed from the air in the process. This is pretty revolutionary.
Why haven’t we already seen a mass push for algae farms if we are aware of all of these benefits? First of all, algae grows so incredibly fast that it may be difficult to manage and process. It is possible to invest in technology that would allow for better utilization of large amounts of biomass, but at high costs that would cause a time lag in profitability. We are at the point where we must choose between economic profit and environmental profit. Which will it be?
Another potential consequence of algae farming is how this method will affect the pH of the ocean. Put simply, ocean acidification is the result of carbon dioxide from the atmosphere being absorbed by the ocean and reacting with water, which releases hydrogen ions and increases the ocean’s acidity. When algae photosynthesizes, it removes carbon dioxide from the water and thus could reduce ocean acidification. But there is a catch; every ecosystem has a carrying capacity. When this capacity is surpassed, a large influx of biomass will die and sink to deeper parts of the ocean, where decomposers then break it down and release carbon dioxide as a product of respiration. This means that there will be a limbo between growing enough algae to reduce the greenhouse gas effect of carbon dioxide while also not growing a harmful amount.
Kelp forests have a lot of exciting things to offer and, as per usual, its future will likely depend on economics and politics. It will be interesting to see how this protist’s future plays out and how it can fit into the complex puzzle of trying to undo the giant mess that we have created in our atmosphere.