Seaweed has a slew of real-world applications, from food to fuel to medicine, but its greatest aid to us is its remarkable ability to combat climate change. Scientists have found that seaweed and algae are both prime candidates for carbon sequestration. Carbon sequestration involves the absorption and storage of carbon dioxide (CO2) to prevent its release into the atmosphere. Soaring carbon emissions are the main driver of climate change and its many consequences, as modern industry, transportation, and agriculture produce too much CO2 for the planet to sustain. Seaweed, however, truly holds the potential to change the world.     

Every year, seaweed absorbs a staggering 200 million tons of CO2, which it takes in during photosynthesis, and can store it for years, even centuries! Alongside mangroves and salt marshes, it is a significant source of blue carbon, or carbon stored by marine ecosystems and plants. While impressive, the 200 million tons of CO2 seaweed consumes is still far short of the nearly 40 billion tons produced per year. So, how do we close this gap? 

Seaweed farming! Growing large quantities of seaweed in coastal, open, and deep waters provides an eco-friendly method of carbon sequestration. The process for using seaweed to sequester carbon dioxide would go like this: seaweed would be cultivated and allowed to collect CO2. It would then be transported out to open ocean and deeper waters and sunk, preventing the CO2 from reaching the atmosphere. This second step occurs naturally, but human assistance would speed it up and ensure that the CO2 is properly sequestered. The growth of kelp forests specifically is referred to as ocean afforestation. Giant kelp, which can grow up to 200 feet long, is of particular interest to scientists since it stores more carbon than any other species of seaweed. As for algae, scientists have proposed that it can be used for shorter-term, smaller-scale carbon storage. Seaweed farms also remedy more specific effects of climate change. The influx of oxygen and blue carbon would slow ocean acidification, coral bleaching, and ocean deoxygenation. A team of researchers based out of the University of South Pacific concluded that if seaweed covered 9% of the ocean, CO2 levels in the atmosphere could be reduced to where they were before the industrial age!

Fortunately, seaweed farming is on the rise. New England alone has over 40 farms in operation and an additional 100 permitted sites! Seaweed almost seems too good to be true, and all signs point toward it becoming one of our primary tools for restoring our oceans and our planet.
 

Critical Response

1. What is carbon sequestration? 


2. What are three sources of blue carbon? 


3. How much carbon dioxide does seaweed absorb per year? 

 

Imagine diving into the cold coastal waters of Northern California. You look around and are met with the swaying, golden-brown arms of the towering algal giants that surround and safeguard you from predators. The bull kelp forest in which you’ve found yourself is one of the most prolific habitats on the planet, where bull kelp grows more than 100 feet in length. In fact, bull kelp is the second fastest-growing algal plant in the world, and the first to trend worldwide on social media, which is why it is a fitting subject for our first trending topic segment!

Bull kelp thrives in the chilled waters of the northwestern coasts of North America and has historically been highly valued by the indigenous communities that inhabit them. Aside from its traditional use as a food source, bull kelp has been used by the Tlingit tribe to treat earaches. Its stems have been repurposed into ropes, baskets, fishing nets, and the bulbs have been transformed into bowls. Indigenous tribes have strict rules when it comes to seaweed harvesting, and it wasn’t until World War I that bull kelp became a commercial commodity, with the belief that its high potassium content would make it a viable gunpowder ingredient. Pharmaceutical and cosmetic companies have also invested in bull kelp harvest, but with no government-enforced regulations, bull kelp forests have declined greatly.

Thanks to TikTok, bull kelp has been thrust into the public sphere. People came for bull kelp cutting ASMR and stayed to discover all its unique benefits, primarily that bull kelp is fun to eat raw and also makes great pickles. Of course, we have talked about the practical uses of bull kelp, but what about its intrinsic importance to our oceans? How is bull kelp able to form a forest of individuals despite the harsh currents? How does the presence of a kelp forest change the surrounding ecosystem? Continue to think about these questions throughout the article, and you might discover that bull kelp forests are a lot more important than they may seem on the surface…or in the ASMR videos. Click here to see bull help harvesting in action!
 

Critical Response

1. List three items that bull kelp has been used to make:


2. Why has bull kelp risen in popularity?

What comes to mind when you think of seaweed? Probably a green underwater plant you’ve seen in the ocean or the aquarium, or delicious sushi rolls, or a tasty dried, green rectangular snack you’ve munched on. However, seaweed comes in many more forms. In fact, you’ve probably used, touched, and even eaten much, much, more seaweed than you realize! 

First of all, what is seaweed? Seaweed is a broad term for many different kinds of macroalgae. Seaweeds can come in all sorts of shapes and sizes, from microscopic to massive kelp stands. They can also vary in color, mainly categorized into red, green, and brown. These algae play an important role in supporting many food chains in marine ecosystems. In addition to feeding ocean creatures, seaweeds also feed humans!

The most well-known seaweed foods are probably sushi rolls or other Japanese dishes that incorporate seaweed, as well as the packaged, dried seaweed strips/rectangles. Surprisingly, however, seaweed can show up in our food items in inconspicuous and different ways! A compound called carrageenan, which is derived from red seaweeds, is used as an additive to adjust food product textures. Carrageenan can thicken, stabilize, and emulsify dairy or soy-based products, including ice cream and salad dressings!

We not only eat seaweed, but we also put it on our faces! Carrageenan and other seaweed-based compounds are often used for medicinal and cosmetic purposes. In ancient times, Romans applied seaweed salves to treat wounds, burns, and rashes. In the modern era, many skin and body care products use seaweed-based compounds—including many shampoos, face masks, and even toothpastes.

A new, currently developing use for seaweed is as a source of energy, or a biofuel. Scientists are exploring a conversion process, or refining, that changes seaweed into a form that can be burned or consumed, similar to gasoline and fossil fuels. Some advantages of seaweed over traditional fuel sources include that seaweed is easy to cultivate, grows rapidly even in less-than-ideal conditions, and also assists with capturing carbon dioxide.

Which one of these uses for seaweeds surprised you the most? What’s amazing is that there are still so many more creative ways seaweeds can be used that we have yet to explore!

Critical Response

1. "Seaweed" is a term for different species of ___ 


2. What kind of seaweed is carrageenan made from?


3. How did the Romans use seaweed?