Seaweed and its Valuable Use

By Colby Brink

Seaweed. What is it? What is its purpose? To many summer vacationers, seaweed is often dismissed simply as that green slimy stuff which floats on the ocean surface. Many say there really is no real role for seaweed to play in the environment and is only a nuisance. Others say that its sole purpose is in becoming entangled in the legs of all those who come in contact with it by causing them to smell just as it does. The name "seaweed" itself incorrectly implies that these plants have little value. This was the accepted definition until the eighteenth century. They were regarded as "not proper plants" because they had neither flowers nor seeds. Surprisingly enough, seaweed is not what most people think it is, or rather what it can be used for. It's not just that "green slimy stuff" floating on the oceans surface. It can and does have many purposes in the world. With the unique variations of seaweeds that can be found in the ocean, the purposes for them can become quite amazing. A purpose inwhich all seaweed types play in the world today is that they can perform a vital role in our economy. In having said this, we'll now begin our discovery into the different types and colors of seaweeds. We'll also find out the roles that this typical oceanic plant have to provide, much of it being quite good for the world.


What is Seaweed?

From the polars to the tropics, estimates range from 20,000 to 130,000 species of seaweed can be found, but the real figure is probably around 45,000. Between the United States and Africa in the North Atlantic Ocean, lies a free-floating meadow of seaweed almost as large as a continent. This is the famous Sargasso Sea. Christopher Colombus is said to have discovered it as he sailed toward the New World in 1492. Its presence suggested that land was near and encouraged him to continue on. Seaweed plays an important and vital role in the marine ecosystem, providing food and shelter for a host of creatures such as green sea urchins, lobsters, and young fish. It is also an important resource for people. Almost all are algae, which is one of the simplest forms of plant life because they have no roots, stems, leaves, and flowers. This is perfect for the kind of life they live with the constant pounding by the sea. Most of these seaweeds can be seen thriving in underwater beds, floating along the sea surface, and attached to rocks and piers. Seaweeds are divided into three major groups by color: the greens, the browns, and the reds. They cover rocky shores in horizontal bands, with the green seaweeds growing along the high-tide line, brown seaweeds found between the high-and low lines, and red seaweeds living in the waters below the low-tide line. This zonation is regulated in large part by the light availability and by how sunlight penetrates the seawater. Blue wavelengths penetrate ocean waters to greater depths than orange-red wavelengths. Thus red seaweeds (which absorb mostly blue light) are found at the greatest depths, in some cases to more than 70 feet; brown seaweeds are intermediate, and green seaweeds (which absorb mostly red light) are found near or at the surface. Certain red algae has been recorded at growing depths of 270 m.(885 ft.), far deeper than any other known plant life in earth.


Brown Seaweed

Brown seaweeds are either microscopic like atoms , or huge like giant kelps, which grow at lengths of 50 meters or more. Most of these prefer living in cold water so that they can grow extremely large. There are many variations of these brown seaweeds. Ranging from the Focus or Rockweed, to the Macrocytis, the Laminaria, and the Nereocytis. Dinoflagellates are single-cell organisms which form "red seas" and can secrete poisons. Some of these poisons, which are 100,000 times stronger than cocaine for example, attack the human nervous system and can destroy it. These brown seaweeds are quite interesting to look at. Most have small air bladders along their fronds, with the exception of the Laminaria. The fronds long stems called the stipes, and leaf-like blades, are what the plant uses to absorb nutrients from the seawater and carry out photosynthesis. They resemble that of a stem and leaf of the typical land plant. These fronds themselves extend from the holdfasts, which are rootlike devices used for attachment to the rocks. These seaweeds are held up while living at the bottom of the ocean by tiny gas-filled bladders or swellings which are found in the fronds. They act as floating devices to keep the plants closer to the surface, allowing for maximum light exposure. This allows for the process of photosynthesis to occur more easily . A process which is vital to our lives also. In our region of the world, one of the most familiar seaweed's is the Macrocytis, also known as the Giant Kelp. These Giant Kelp which can be found off the coast of California, have tough, leathery root-like branches, and can grow to be more than 150 feet (35 meters) long! The majority of seaweeds are perennial and live more than two years. The claim to fame which these particular seaweeds possess is that its the longest alga in the world (200 ft.)! This seaweed grows over 17 inches per day, and can actually double their weight in five to ten days! "Recent research shows that seaweeds produce more vegetation per year than alfalfa fields and tropical rainforests." The kelp forests off our coasts today sprawl with such seaweed. Spanning over 44,000 acres of ocean floor they support more than 800 species of marine life (Tennesen, 1992). Some of the creatures that live under the canopy of brown seaweed includes barnacles, blue mussels, and starfish. These grazers have been found in seaweed beds in numbers close to 600 per square yard.

When harvesting these brown "Giants", a gummy substance known as alginates and algin (or fucin) are extracted. As a result of extracting alginates or algin, many uses have been developed. To name a few such uses, they include dairy products, adhesives, textile products, rubber, pharmaceutical products, paper products, and some other miscellaneous products as well. This brown seaweed has been a part of human life for past centuries, and will continue for centuries to come. With it humans have developed unique purposes for such strange plant life. "During World War II, the Hercules Powder Company near San Diego extracted potash and acetone from Kelp to manufacture gunpowder" (Tennesen, 1992). With seaweed, playing such an important role in the production of these items in todays economy, what other source's would we turn to if we were to not have such readily available "green slimy stuff" at our fingertips ?

Red Seaweed

One of the most diverse groups today is the Red Seaweed. They are also some of the most beautiful! Examples of these include the Rhodophyta (red algae), the Porphyra, the Gracillaria, and the Chondrus Crispus of Irish Moss. This fan-like Irish moss is one of the most common of the red seaweed species. It forms a dense mat which provides protection to small sea creatures and other seaweeds from the strong waves. The green sea urchins depend on Irish Moss for a source of food, while sea gulls, codfish, and lobsters feed on such urchins (Dybas, 1995).

The Chondrus crispus, a marine species of Rhodephyta, is one of the most widely used and eaten seaweeds. Yet, there are few people that actually know the natural appearance of this special seaweed. "Although human diets rarely include C. crispus in its natural form, in other countries this fresh seaweed is still collected and home-processed for use as a thickener in porridge and desserts" (Lobban and Wynne, 1981).

Green Seaweed

Green seaweeds are very similar in color to the stems of flowering plants. Some, like the bright green sea lettuce, quickly overgrowing rocks and crowd out other species. Sea lettuce also grows at the high-tide line on pilings, and buoys. It may even be found anchored to pebbles and shells on sandy beaches.

Agricultural Uses

As we have mentioned seaweeds have been used in the Agricultural industry for centuries now, though only seaweeds from the brown and red zones are commercially harvested. The earliest traces of life on earth, about 3.5 billion years old, include forms of blue-green algae equipped with chlorophyll. Many tests have been performed on these enormous plants to show the improvements that they have made on plants other than themselves. Kelpak for instance, which is a new liquid seaweed concentrate, is made from brown kelp and harvested near South Africa's western coast. It is liquified without heat, chemicals, freezing, or dehydration. In some of these tests performed, a dilute solution was applied to plants as a soil soak or leaf spray. The growth of these plants was tremendous! The plant which was doused with seaweed had an improved root growth and yield which had increased by up to 40 and 60 percent! It had accelerated marigold flowering, and also increased the size and chlorophyll content of the swiss chard. All of these effects primarily were attributed to natural growth promoters in the seaweed! The rich agricultural crops typical of Northwestern France are attributed directly to regular use of seaweed fertilizer. The seaweed industry itself is relatively valuable because it can be used as fertilizers or even a substitute for soil. "This seaweed has been used by the agricultural industry in animal fodder and in fertilizers that improve the nutrient content as well as the mechanical properties of the soil" (Libyan and Wynne, 1981). This in turn has had a tremendous result on the plants and animals that directly consume this seaweed. Growth, health, and quality have all been a result of this added fertilizer.

Kelp has been found to have many important and useful substances for todays economy. Some of us have never thought of or realized the fact that some part of seaweed could be in the very thing we put on and wear each day. Could this be the reason why your lipstick stays on so well, or maybe this why in some of todays moisturizers that you wear causes your skin become really soft and smooth. Other helpful ways inwhich seaweed benefits todays society can be found in the kelp of San Diego. This kelp is harvested on a daily basis. From it, a gelatinous compound called algin is extracted. This extraction process produces a fishy-smelling substance. Getting rid of this material seemed to be a hazardous task until three inventors from Damco (a truck and heavy equipment rental co. in Chula Vista, Ca.) accidentally discovered that this "slimy stuff" could be used to put out fires. They found it was able to absorb and contain the liquid fuel spread by fire fighting efforts. The way they stumbled across such a fire stopping agent was to the surprise of two gentlemen who began testing some oil-absorbent materials. During one of the random fuel tests performed, the blaze they received was a little bigger than anticipated. In a rush to put it out, the two men threw the nearest thing they had on to the fire. This of coarse just happened to be the dried kelp nearby. To their amazement the kelp quickly doused the fire in seconds (Nobbe, 1994). Taking advantage of such a wonderful discovery, Damco began making fires-suppressant bricks, flakes, and powder. The company mixed the kelp sludge with water, smoothed it out in a two inch layer to dry in the sun, and mulched it into something which looked like kitty litter. Each of the 11-15 lb. bags would retail for about $15 a cubic foot (Nobbe, 1994).


Seaweed as Food

Along with helping put to put out blazing fires, or accelerating the growing process of plants, seaweed is used for a variety of other purposes as well. One of them being food for the human family. "Generally, kelp is valued for its micro nutrients (e.g. iodine) and to a lesser extent its vitamins and amino acid content" (Lembi and Waaland, 1988). Japan has come to rely heavily on cultivated Undaria, which is almost always eaten in fragments. The cultivation of Laminaria is becoming increasingly important in meeting marketing requirements as it is used to prepare many different dishes to be eaten. The world production of seaweed is providing the agricultural and other industries with a good source of protein, fiber, vitamins, and minerals. " There is now evidence that dates back to 600 and 800 B.C., that the Chinese used seaweed as food. It is also likely that the Japanese, Hawaiians, Greeks, and Romans utilized various seaweed's in ways that gave rise to todays modern usage" (Lobban and Wynne, 1981). At one time in Great Britain, substantial industries existed for the manufacture of soda and of iodine from seaweed. This market for cultivating edible kelp is and will continue to grow at a rapid pace in todays society. This will result in the decrease access to wild plants, an increase in the human population, the manufacturing of new kelp products, and increased acceptance of established products.

Industrializing Seaweed

Carrageenans, a term that is used interchangeably with C. crispus and Irish moss, plays an important role in our economy in a variety of different ways. For instance, it is used to smooth consistency to icecreams, puddings, processed cheeses, jams, light beer, and other food products. In the pharmaceutical industry, the use of carrageenans range from stabilizers, emulsifiers or colloids for suspensions, and gel coatings for pills, to bases for antacids, cough syrup, and ointments.

"Recently Porphyra nereocytosis has been examined in California as an alternative to the importation of nori from Japan, but at present its exportation is regarded as scarcely economical" (Woessner, Sorenson and coon, 1977). Alvaro Israel, of the Israeli National Institute in Haifa, has identified 107 types and 493 varieties of seaweed used by human beings. Most are grown and consumed in the Far East and the Pacific in accordance with long traditions. Japan has become the most important user of Pophyra. Dating back to at least 533-544 A.D.. Even today it "continues to be highly valued in soups and as flavoring in many dishes" (Lembi et al., 1988). Following the preparation process that come with nori, it is packaged in bundles of ten and sold as a paper-thin purplish black sheets on the open market. A principle natural algal food product is laver, or Toasted nori (yaki-nori). This is ordinary nori pre-toasted and sold in an air tight packages. Such preparation is a major industry. "In 1903 it was even being put into tins for boiling with Soya bean sauce and in Japanese railway stations. It was taking the place of the inevitable sandwich that had been offered to the public under the name 'SUSHI' (Chapman and Chapman 1980).

Another way seaweed's are of great importance to our environment and economy is through the use of green seaweed's. These seaweeds are sometimes better known as Chlorophyte. These are very similar in color to the stems of flowering plants and can be found anchored to pebbles and shells in sandy beaches. Within these Chlorophyte, "certain micro algae have an unusual breadth of nutritional quality when compared to the higher plants of our diet. Among the micro algae of commercial importance, Sprulina stands out" (Lembi et al., 1988).


Medical Uses

Spirulina also has some therapeautic applications a well as being a part of our everyday diet. For instance, "ongoing research at Harvard Medical School also supports the use of Spirulina extracts in the treatment of certain cancers" (Lembi et al,. 1988). Some other published and unpublished experiments on potential therapeutic applications of Spirulina include that of: external wounds on human subjects, hypothyroidism on poultry, oral cancer, obesity, diabetes, cataracts, and allergies. Each of these being found on humans. Any of these therapeautic applications which are listed above, if they are confirmed, could support the cost of Spirulina.

In Todays economy, seaweeds of all colors, shapes, and smells, have come to play a huge role in each of our everyday lives. For centuries seaweed has provided us with the raw materials needed for the production of numerous items and has indirectly served a vital and significant role to our economy by providing many jobs. In Asia, the 530,000 hectares of seaweed farmed by 250,000 family businesses provide 950,000 jobs. Without this enormous source of plant life growth found in ponds, freshwater lakes, and oceans, many jobs would not be had, as well as lives benefited. What a wonderful thing it is to know we have such helpful plants throughout our environment. Though how odd this plant many look, may we continue to use these sea beds with caution, for they belong to the ocean, not to us.



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New York: Cambridge University Press.

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Nobbe, George. March 1994. Kelp, the Firefighter's friend.

Omni: p. 29

Organic Gardening: sep/oct 1990. Help From Kelp vol. 283; p. 16

Tannen, Mark. March 1996. The Seaweed Factor.

New York Times; vol. 120; Is. 50376 p. 66

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