What is seaweed?
Seaweed is a type of algae that lives in the ocean. Algae constitutes a very large and diverse group of living organisms, and can be further divided into two sub-groups, Macroalgae and Microalgae.
Microalgae are free-living unicelled (single-celled) organisms, that are mainly phototrophic, which means that they catch photons and CO2 and convert it into sugar as energy storage. This is known as photosynthesis. Some of these algae became, at one point in time, specialized to life on land as chlorophyll, which is the green pigment in the leaves of plants, and is essential for their ability to perform photosynthesis. Microalgae exists everywhere in the ocean, and will, under the right circumstances, bloom to gigantic proportions. This happens naturally every spring, but it can also arise from other circumstances, and sometimes it can have devastating consequences for other sea life. Microalgae are also known as phytoplankton.
Macroalgae, on the other hand, are multicellular, commonly known as kelp and seaweed. Occationally you'll hear "sea plant" being used to describe kelp and seaweed, but macroalgae and plants are very different organisms. Seaweed doesn't have a root system that absorbs nutrients and water, instead is has an organ called "holdfast" which secures the blade firmly to the seabed while the nutrients are absorbed in the blade. "Blade" and "holdfast" are macroalgae analogues to "leaf" and "root" in plants, though they function very differently. Macroalgae can be divided into three groups, red, green and brown, which are the three pigment types that exists. They all perform photosynthesis, but they differ in color. All three categories have species that are well suited for human consumption, but so far almost all of the macroalgae cultivated in Norway are brown macroalgae. There are several reasons for this, some algae have very complicated life cycles, but brown macroalgae are much larger and have much higher biomass yield than the other types.
The difference between kelp and seaweed is far less important, but often times it's part of the name, like Sugar Kelp. Seaweeds are generally smaller and live in the shallows close to shore, kelp prefers deeper waters. Even though these differences exists, we commonly use "seaweed" to describe cultivated macroalgae.
Seaweed cultivation is a subject that many people are interested in because it opens up new venues to solve many of our problems related to production of raw materials and food. Gloomy predictions about food shortages and resource depletion have all been put to shame by advances in technology, which has made agriculture ever more efficient, and pushed the limit of production and resource exploitation to new heights. Despite these advances, agricultural land is under ever more pressure, and every year huge new areas are being converted to agriculture.
This trend is primarily driven by global population growth, and in many places of the world the exploitation of natural resources has hit the maximum sustainable limit. In South-America and Asia primary rain forests are being cleared to make room for soy, rapeseed and palm oil plantations. These crops are important raw materials, and the demand is ever increasing. If one wants to relieve the pressure on these rainforests, one has to provide alternatives. Seaweed is just that.
Seaweed is cultivated at sea, and can be expanded and increased almost indefinitely without having to chop down a single tree. The available area is practically unlimited, but developing a whole new industry will take time. Those who wish to reduce the pressure on the world's rainforests can help by choosing seaweed wherever it exists as an alternative.
Agriculture has been developed through thousands of years from the most primitive state imaginable, to today's hyper advanced, mechanized and high tech industry. The plants that are used have undergone a profound and human guided evolution, from the primeval state to the highly productive, super yielding miracle plants that we have today. They have in fact become so specialized that they wouldn't be able to survive in nature today, they need us as much as we need them.
Seaweed cultivation is a brand new industry, in the west anyway, and the species are still in the primeval state. There is a vast potential for improvement and specialization, but we don't have to wait thousands of years for seaweed to start replacing plant products. Seaweed cultivation is admittedly more expensive and difficult than any plant cultivation today, but that could soon change.
Seaweed cultivation, in stark contrast to agriculture, has a huge positive effect on the environment. Seaweed utilizes the sunlight and nutrients in the water, without the use of fertilizers. The seaweed absorbs carbon dioxide and nitrogen from its surroundings, and adds oxygen, which helps the marine environment. Seaweed cultivation also leads to more resources being invested in knowledge and understanding of algae and marine environments. This may eventually solve bigger problems, like why the arctic kelp forests have been receeding for the last 30 years, and all but disappeared from some areas. Kelp forests are extremely important for the many species that live there and depend on it. When their habitat disappears so does the entire food chain and the diversity of species along with it.
It's not just as food or raw materials that seaweed can have great value, seaweed can be used in anything from medicine to energy. This huge range of application can be utilized with better technology, and this will open up countless new markets for seaweed. Many of these markets could be using seaweed today if it were not for the high costs. If people choose seaweed whenever they can, they are directing the markets to invest in better technology for both seaweed production and processing. Seaweed is the "plant" that can do anything and everything, but it needs a push.