Widespread seaweed cultivation is emerging in the United States, the United Kingdom, and India, not only because seaweed has become an important food in many parts of the world because it grows quickly, is relatively easy to grow and is nutritious, but also because it could also become an energy source that powers cars and airplanes.
The rise of seaweed cultivation
Seaweed is not only a food source for some countries and regions, but also a source of livelihood for these places, and the large-scale cultivation of seaweed has made it one of the fast-growing food sources in the world, and seaweed has many potential uses in addition to food. For example, it can help restore ecosystems and help deacidify the oceans.
Some scientists call seaweed the "Swiss Army Knife" to combat climate change and the planet's challenges, and one of the current challenges facing the planet is a sustainable source of aviation fuel. The vast majority of aircraft are powered by fossil fuels and account for nearly 2.5 percent of the world's carbon dioxide emissions, a number that sounds small, but it's the highest carbon emitting thing the average human can touch.
Efforts have been made to research biofuels from land-based crops as an alternative to chemical fuels, but biofuels themselves have sustainability problems, such as heavy land and water use and harm to biodiversity.
But on the other hand, seaweed, seaweed only needs a small part of resources to grow, basic seaweed as long as there is an open sea and a lot of sunlight can grow, they absorb a large number of nutrients from the depths of the ocean, very suitable for use as biofuel, can provide a considerable amount of fuel for long-distance transportation.
How can seaweed be used as a new energy source?
Just as there are Amazonian, Congo, and Borneo forests on land, the ocean has its "primeval forests." Underwater forests are formed from seaweed, a type of algae that, like other plants, absorbs solar energy and carbon dioxide to grow through photosynthesis. The largest can grow to tens of meters tall, forming a forest canopy.
Seaweed, as a biomass resource, can be converted into a variety of new energy sources, including biofuels, biogases and bioelectricity. First, seaweed can be converted into biofuels such as biodiesel and bioethanol. In experiments, scientists found that by pressing seaweed, yeast fermentation and other treatments, the carbohydrates in it can be converted into ethanol.
At the same time, the oil in the seaweed can also be extracted to make biodiesel. Second, seaweed can be converted into biogas through biogasification technology, most commonly methane. Or after drying and crushing, seaweed can be put into a biogasification reactor for heating and decomposition to produce gases such as methane.
Finally, seaweed can also be used for bioelectricity production, which is related to the fact that seaweed itself is rich in a variety of nutrients, and the seaweed is put into a bioreactor for microbial fermentation, which can produce gases such as hydrogen and methane, as well as electricity. In short, seaweed can be converted into new energy in a variety of ways, which is of great significance for solving energy problems and environmental problems.
Seaweed can be broadly divided into red, green, and brown, and they have very different properties, just like terrestrial plants, depending on the species and where they live. In addition to being an energy source, seaweed can also help solve some other types of problems. Examples include reducing methane production in cows and other ruminants and capturing and storing carbon dioxide.
As a food, seaweed can increase protein and nutrients in foods, providing additional health benefits in some new food therapies. In wastewater treatment, seaweed can also help absorb excess nutrients from wastewater. In materials science, seaweed can create new materials such as bioplastics, packaging and textiles.
Negative effects of seaweed
Although seaweed has many uses and can occupy multiple markets, it can be grown as a nutraceutical, textile fiber and fertilizer. But in some cases, seaweed ecosystems may produce more carbon than they capture, which may outweigh the benefits for net zero.
Before seaweed is used as a new energy source, the most important use is the carbon capture effect of its marine forest characteristics, but verifying whether the carbon dioxide fixed by seaweed through photosynthesis can be locked in for a long time is extremely complicated. There are differences between species and ecosystems, and the interaction of various organisms living on and around seaweed communities must be taken into account.
When the surrounding coastal waters wash the seaweed canopy, seawater brings large amounts of plankton and other organic matter from farther out of the sea. This provides additional food for filter feeders such as sea squirts, shellfish that live in seaweed, and bryozoans that eventually cover many seaweed leaves.
When these organisms consume this extra food supply, they exhale more carbon dioxide in addition to the carbon dioxide produced by eating seaweed. Individually, the number is small. But at the ecosystem scale, their number and ability to filter large amounts of water are enough to distort the balance between carbon dioxide inflow and outflow.