Seaweed
Seaweed encompasses a diverse group of marine algae, with over a thousand species thriving in oceans and waterways worldwide. It plays a vital role in marine ecosystems, providing both habitat and food for various marine organisms. Harvested by humans for centuries, seaweed is widely utilized in food products, cosmetics, and fertilizers. The rising demand for seaweed, particularly in regions lacking direct access to marine environments, has led to the establishment of commercial seaweed farming, notably in several Asian countries since the 1950s. This sustainable form of aquaculture is praised for its minimal resource requirements and ecological benefits, including water filtration and providing habitats for other aquatic species.
Seaweed is classified into three main categories: red, green, and brown algae, with distinct characteristics and uses. Edible varieties, such as nori and aonori, are integral to traditional cuisines, especially in Japan and Wales. Beyond culinary applications, seaweed extracts are increasingly valued in skincare for their potential anti-aging properties and moisturizing benefits. However, reliance on single-crop seaweed farming can pose economic risks for coastal communities, prompting recommendations for diversification to mitigate vulnerability to crop failures. Overall, seaweed remains a crucial resource with multifaceted applications across different cultures and industries.
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Seaweed
Seaweed refers to a wide range of marine algae. More than one thousand types of seaweed grow throughout the world's waterways. Seaweed is a staple of marine environments, providing a food source and living area for many marine animals. Seaweed is also commonly harvested by humans for use in numerous food products, cosmetics, and fertilizer.
Background
After the discovery of seaweed's many uses, several countries began to consume far more seaweed than they could naturally harvest. Additionally, demand for seaweed products began to rise in areas with no nearby coastline or large waterways. In the early 1950s, several Asian nations saw opportunity in this demand. They began commercially farming useful species of seaweed, such as nori and aonori. Many plains of shallow water were turned into large-scale seaweed farms.
Unlike fish farming, seaweed farming is considered one of the most sustainable and ecologically beneficial forms of aquatic farming. Seaweed does not require careful tending, feeding, or heavy fertilizers to thrive. It simply needs to be planted and monitored until the crop is ready for harvest. Additionally, large concentrations of seaweed naturally filter bodies of water, helping to counter pollution and leaving the ecosystem cleaner than before.
Seaweed farming can also occur in conjunction with other types of aquatic farming. Large, tightly packed fields of seaweed provide ideal environments for crustaceans, allowing farming of species such as shrimp and prawns to take place inside seaweed farms. Seaweed fields can also provide an excellent breeding ground and nursery for young fish, protecting them from natural predators and offsetting some of the negative environmental effects associated with traditional fish farming.
While farmed seaweed is extremely valuable to many coastal communities, its economic dominance is not always beneficial. Communities that grow dependent upon the farming of a single crop become extremely vulnerable to anything that damages it. An unexpected disease can hit a crop, wiping out much of a year's harvest. When this happens to coastal communities that rely on seaweed farming, the results can be disastrous. Many governments urge coastal farmers to diversify their aquatic crops to prevent this from happening.
Overview
Seaweed is commonly divided into three categories: red algae (Rhodohyta), green algae (Chlorophyta), and brown algae (Ochrophyta). When these classifications were first drafted in the mid-nineteenth century, the categories were sorted by color. However, while modern classifications utilize the same names, the process of sorting seaweed into each phylum is more complicated. While pigmentation still plays a role, cellular composition, anatomical descriptions, energy storage methods, and the identification of different types of chloroplasts have all become factors in sorting new species.
Most green seaweed contains chlorophyll and other pigments in similar proportions to green terrestrial plants. For this reason, their protrusions have a similar green color. Some green seaweed is composed of a single cell, while other types are multicellular. This family of seaweed often has a symbiotic relationship with native animals.
Green seaweed grows in both saltwater and freshwater varieties. Unlike many other aquatic plants, some types of seaweed are capable of thriving in both freshwater and saltwater. For this reason, green seaweed can commonly be found in the mouths of rivers where freshwater and saltwater mix.
Brown seaweed gets its color from a pigment called xanthophyll. The pigment masks the expression of chlorophyll, reducing the seaweed's expression of the color green. The kelp family, a grouping of large seaweeds, is composed entirely of brown seaweed.
Species of brown seaweed store their fuel in the form of sugars and concentrated alcohol. Unlike green seaweed, brown seaweed exists exclusively as multicellular organisms.
Red seaweed takes its color from the pigments phycocyanin and phycoerythrin. It stores its energy in simpler variants of starch, and its cell walls are made of cellulose, carrageenan, and agars. While most red seaweed is multicellular, a select few are composed of a single cell. Red seaweed contains chemicals that are commonly used to stabilize food products and spur the growth of beneficial microorganisms.
Seaweed is harvested for a variety of uses. One of the most common uses for seaweed is in food products. Different breeds of seaweed have different tastes and textures, making the plants an incredibly versatile food group. Nori, a type of red algae, has been eaten in Japan for centuries. During the Edo period, Japanese cooks began to experiment with other means of preparing nori as food. They ground the seaweed into a paste, and then spread that paste into a thin, paper-like product. The sweet, edible paper was then used to wrap sushi rolls and traditional Japanese rice balls. Additionally, ground up nori was used to season soups and pasta.
Aonori, a type of edible green seaweed, was commonly eaten in both Wales and Japan. In Wales, aonori was ground into a paste that could be spread onto a variety of traditional dishes. It could also be fried and eaten as a delicacy. In Japan, aonori was usually dried and powdered, after which it could be sprinkled onto noodles as a powerful seasoning.
Many other varieties of seaweed are used in Asian cultures for flavoring. Kombu, a stiff, dark-colored seaweed, is commonly used in the flavoring of soup stock. Hijiki, another dark-colored seaweed, is often dried and eaten with vegetables. Several types of kelp can also be sautéed or included in salads.
Liquid seaweed has become a popular fertilizer. Farmed brown seaweed, often a variety of kelp, is ground up and sold to be spread on lawns, houseplants, crops, and sports fields. Brown seaweed contains a large number of chemicals that facilitate healthy plant growth, including iron, nitrogen, and magnesium.
Uses for seaweed have also been found in the cosmetics industry. Designers of skin care products speculate that seaweed extract helps slow the breakdown of collagen in skin. This helps skin retain its elasticity longer, and may help to stop wrinkles from occurring. Industry experts also argue that seaweed extract helps moisturize skin, keeping it healthy and supple.
Bibliography
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"Rhodophyta: Red Algae." Seaweed.ie, www.seaweed.ie/algae/rhodophyta.php. Accessed 26 Nov. 2024.
"Seaweed Taps into the Anti-Ageing Trend." Cosmetics Design Europe, www.cosmeticsdesign-europe.com/Market-Trends/Seaweed-taps-into-the-anti-ageing-trend. Accessed 5 June 2017.
"What Are Seaweeds?" Seaweed.ie, www.seaweed.ie/algae/seaweeds.php. Accessed 26 Nov. 2024.
"What Is Seaweed?" National Oceanic Service, National Ocean and Atmospheric Administration, 16 June 2024, oceanservice.noaa.gov/facts/seaweed.html. Accessed 21 Nov. 2024.