We all know seaweed as the slimy, sometimes smelly thing that washes up on the beach. But when we look further at these green algae, we see how valuable seaweed can be.
The cultivation of seaweed and the marketing if it has come to improve economic conditions and limit the pressure on fishing. Seaweed is grown in large numbers in Asian countries such as China, Japan and Indonesia, but since a few years, seaweed farming has become increasingly popular in the western part of the world.
In this paper I will start by briefly explaining what seaweed is. Afterwards I will explain how seaweed farms works and for which seaweed is used. At the end I will list some advantages and disadvantages.
Seaweeds are also called macro-algae. Micro-algae are organisms that consist of one cell. These single-celled algae are known by the green layer that appears on polluted water.
Seaweed can be subdivided into three groups based on their color: green seaweeds, brown seaweeds and red seaweeds.
Green seaweed is the basic form. This type of seaweed is mostly used as food. The green color is due to the chlorophyll present in seaweed for photosynthesis.
The brown seaweed are also usually used as food. The most famous brown seaweed used as an ingredient is the Laminaria. This algae has a high nutritional value and is often used in the Eastern cuisine.
Red seaweed is also used as a food source, in particular for making the hydrocolloids agar, an ingredient used as a binder, and carrageenan, an ingredient known for its gelling, thickening, and stabilizing properties (McHugh, 2003).
A big advantage of growing seaweed is that there is no land area needed. The entire process takes place in the water where the seaweed can grow without pesticides, plant food or fertilizers. The variation in types of seaweed is very extensive. For example, there are suitable seaweed types for both cold and warm water and for deep or shallow water.
Seaweed can be grown in various ways. For certain types of seaweed. Thick ropes are used on which the seaweed is sown. After that, the lines with seaweed are brought to an open area in the sea where they are submerged. When the seaweed can be harvested, the farmer can cut the seaweed to the correct length so that it can continue to grow. Another possibility is that he removes the lines as a whole and takes them to the mainland to remove the seaweed from the ropes.
Other types of seaweed are grown using nets on which spores are deposited. This method takes the tides of the sea into account. The nets are fixed into the seabed at a place where the seaweed will be above water at low tide and where it will be completely submerged at high tide. (Flora, 2019).
The use of seaweed
It was previously said that seaweed is used as a food source for humans and animals. Seaweed is filled with antioxidants and nutrients such as sodium, calcium, iodine, zinc and vitamin B-12. That makes seaweed a good substitute for meat. Also because seaweed is a source of proteins, it is called a superfood.
All these good ingredients ensure that seaweed is a very valuable product for medication in the pharmaceutical sector.
Research by Cordis (Cordis, 2017) shows that seaweed can also be used as a biological substitute for plastic. To process seaweed into the basic components needed for making bioplastic, a whole process is needed. First the seaweed is dried, then it is milled. As a final step, the seaweed powder is chemically treated. In this condition, the seaweed can be reworked into the bioplastics.
Nowadays, seaweed can be found in creams, shampoos, face masks, bath salts, etc. Due to the presence of carrageenan in seaweed, seaweed is more commonly found in cosmetics. Carrageenan is a substance that appears to be good for skin elasticity (McHugh, 2003).
The impacts of seaweed (farming)
Seagriculture has a major environmental impact. It is generally known that a large part of the greenhouse gas CO2 ends up in the atmosphere, but about half of that greenhouse gas ends up in the ocean. Together with water and certain minerals, which are sufficiently present in the sea, seaweed is able to absorb CO2 and convert it into energy and O2. This is due to photosynthesis (Bruhn et al, 2017).
Another advantage of seaweed farming is that seaweed brings a wide variety of organisms. This indirectly ensures that coral reefs are preserved. This is also an advantage of seaweed farming.
For the cultivation of seaweed hardly any water, soil or fossil fuel is required. As a result, the environmental impact of this protein source is much lower than that of animal protein sources.
In addition to the advantages of growing seaweed, there are also some disadvantages.
The first problem is that farmers use the wood from mangroves to use as a pole to attach their ropes. For this, the mangroves are cut down and these important and useful elements are becoming increasingly scarce.
For its growth, seaweed needs a lot of natural nutrients. These are present in the water, but due to the immense rise in seaweed farming, it is possible that the nutrients will run out. The decrease of nutrients in seawater will show short-term and long-term effects on marine life and seaweed farming itself. (Phillips, n.d.)
As an answer to the main question ‘What is seaweed and why should we use it?’, we can say that seaweed is a very valuable product with a lot of antioxidants and nutrients. Both as a food source and as a product for external use, it has many advantages. The use of seaweed is already well established in our daily lives, but people are often not aware of the fact that seaweed is present in the products they use.
Although there are some disadvantages associated with the cultivation of seaweed, I think we can say that the benefits prevail. Seaweed is a good sustainable alternative for the production of vegetables and meat on the land surface.
Seagriculture is a concept that is gradually making its name in the world, but it will become increasingly important over the years.