Single-celled algae: single-celled marine phytoplankton with little or no swimming ability, suspended in water and flowing with water, among which diatoms are the most, and dinoflagellates, green algae, cyanobacteria, golden algae, etc. Because of photosynthesis, they are only distributed in the upper ocean (about 0 ~ 200 meters) and are one of the main components of marine primary productivity.
Seaweed, like terrestrial plants, can carry out photosynthesis under light conditions.
Macroalgae: Macroalgae mostly belong to marine benthic algae and have no real roots, stems and leaves; Cells have chlorophyll, so all algae have the function of absorbing nutrients for photosynthesis; There are three kinds of algae reproduction, namely vegetative reproduction, asexual reproduction and sexual reproduction. The reproductive structure is very simple. The basic structure is that the spores or zygotes of single cells leave the mother in the form of single cells and directly develop into new individuals. Life history is also divided into different types due to different stages of meiosis. They belong to non-vascular spore plants and mainly grow in rocks or swamps in intertidal and subtidal zones. They are important marine living resources and major producers of marine organic matter. Seaweed can be eaten directly by human beings, such as laver, kelp and Ulva. Swertia japonica and seaweed are well-known medicinal seaweeds used to repel pythons; Another important use is to extract fucoidan and other compounds from seaweed, which is widely used in medicine, health, food industry and other industries.
Seaweed, like terrestrial plants, can carry out photosynthesis under light conditions and convert inorganic substances into organic substances. Therefore, the distribution range of algae is mostly in the coastal shallow sea or the upper layer of seawater that can be penetrated by light. Because algae need different light intensity and wavelength, their distribution depth is also different. Green algae mainly absorb and utilize red light, mostly distributed in the upper layer of 5~6 meters water depth; Brown algae absorbs and uses orange light and yellow light, so it lives in the water depth of 30 ~ 60 meters; Further down are red algae and blue algae.
Seaweed is a primitive plant. Different from higher plants, it has no real differentiation of roots, stems and leaves and will not blossom and bear fruit. It is attached to rocks or other substances by fixators similar to the roots of higher plants.
Common algae in brown algae
Seaweed has high nutritional value. Some algae are not only edible, but also good industrial raw materials and additives. Agar extracted from red algae has been widely used in food industry, mainly used to produce jam, cream, juice and other ingredients. When making cold food, just add 0.2% agar to make it delicious. The properties of agar can also accelerate the dissolution of milk powder and prevent milk from caking. Jelly and candy made of agar are one of children's favorite foods. Agar is also an indispensable raw material in cosmetics. In the pharmaceutical industry, agar is also widely used to make drugs. People's common emulsions, capsules and ointments all contain different amounts of agar.
Algin extracted from brown algae can prolong the fresh-keeping period of flowers and can be preserved in beer for a long time without deterioration. According to statistics, fucoidan has more than 800 uses. Sodium acrylate sulfate (PSS) made from fucoidan has obvious curative effect on the prevention and treatment of ischemic cardiovascular and cerebrovascular diseases and hyperviscosity syndrome, and it is a semi-synthetic marine new drug with special curative effect.
brown alga
Spirulina is the earliest photosynthetic organism on the earth, and people who eat spirulina are very healthy. It is found that its nutritional components are very rich and comprehensive, and the protein content is more than 20 times higher than that of any iron-containing food. The nutritional value of each gram of spirulina is equivalent to the nutritional sum of 1000 grams of vegetables. Spirulina has many medicinal functions such as anti-radiation, anti-ulcer, anti-tumor and immune regulation. Some people say that spirulina will become the most popular health care product.
spirulina
Seaweed culture in China has a long history and is becoming more and more common. The main cultivated varieties are kelp, laver and Undaria pinnatifida. At present, China has become a big country in seaweed culture.
Seaweed is the main body of marine plants and a great natural wealth of human beings. At present, there are more than 100 kinds of algae that can be used as food. Scientists divide algae into planktonic algae and benthic algae according to their living habits.
Benthic algae are bright and beautiful in color, including green, brown and red. Scientists divide algae into three categories according to their colors: green algae, brown algae and red algae.
Seaweed is the main body of marine plants.
The body of green algae is grass green. There are about 6,000 species of green algae, 90% of which are produced in fresh water, and only 10% live on rocks in intertidal or subtidal zones. Green algae have single cells and colonies; There are filiform and flaky. The most common marine unicellular green algae is Platymonas, which is rich in protein and is a good bait for small and medium-sized marine animals. The most common multicellular green algae are Ulva lactuca and reef membrane (called sea spinach or sea cabbage by fishermen along the coast of China), which are popular marine economic vegetables. There is also Enteromorpha, which can be used to make Enteromorpha cakes. It tastes delicious. In addition, there are feather algae, bracken, sea pine, umbrella algae and so on.
The body of green algae is grass green.
The algae body of brown algae is brown, multicellular, filamentous, flaky or leaflike, some are saccular, tubular, cylindrical or dendritic, and generally have disc-shaped or branched fixers or rhizomes. There are stems and leaves on the rhizome, commonly known as pseudostems and Ye Jia. Large species of brown algae, such as kelp, can grow to 7 ~ 8 meters long; Giant seaweed can grow to 300 meters long and is known as "undersea forest". Most of them grow on rocks in the low tide zone or below the low tide line.
The algae body of red algae is purple or purplish red, mostly multicellular, filamentous, flaky and branched. Various shapes, such as circle, ellipse, belt, etc. Most red algae like to live in the deep sea, growing near the low tide line and 30 ~ 60 meters below the low tide line, and a few species can grow on the seabed of 200 meters. There are more than 2,500 species of red algae, among which the most common species are Porphyra, Phaeophaga, Chaetoceros, Myxomycetes, Ferns, Myxomycetes, Scolopendra, Sargassum, Polysiphonophora and Parthenocissus. Porphyra purplish red, flaky, fresh or dried. Dried laver is the best-selling non-staple food in the market.