Seaweeds

Japanese: 海藻 - かいそう（英語表記）seaweeds

The taxonomic groups of plants that grow in the sea include Chlorophytes (seed plants, Chlorophytes, Prasinophytes, etc.), Euglenaphytes, Xanthophytes (Phaeophytes, Diatoms, Raphidophytes, etc.), Haptophytes, Dinoflagellates, Cryptophytes, Rhodophytes, Prochlorophytes, and Cyanobacteria. However, when people generally refer to seaweed, they are more likely to refer to the large-bodied Chlorophytes, Phaeophytes, Rhodophytes, and Cyanobacteria. Here, we will mainly explain these four groups.

[Moriaki Shinzaki]

Blue-green algae

Blue-green algae / [Science] Cyanophyta The main pigments are chlorophyll a and phycobilin, and the body color is indigo-blue or purple-red. Blue-green algae are originally single-celled algae and microscopic bodies, but when many of them gather together, they form colonies that are visible to the naked eye. These colonies are considered seaweed, and they are indigo-blue in color and grow as hair-like bodies about 4 centimeters long. They grow abundantly in the upper layers near the high tide line on rocks, cliffs, and piles on coasts all over Japan in summer. Classification is difficult, but there are many genera, including Lyngbya , Rivularia , Oscillatoria , and Calothrix . Originally, these cyanobacteria are warm-climate species, so their growth period and distribution area were somewhat limited and they were not very noticeable. However, as seawater pollution and eutrophication have spread, their growth volume has increased and the growth period has become longer, and now they are commonly seen all over Japan.

[Moriaki Shinzaki]

Green algae

Green algae / [Scientific] Chlorophyta The main pigments contained are chlorophyll a and b, and they are similar to terrestrial plants, with the main body color being green. There are various body shapes, such as soft membranous flat or tubular leaves such as Ulva, Laver, and Human Egusa, thin branched body branches such as Cladophora and Hanemo, and thick branched body branches such as Mill. There are also types that have differentiated leaves, stems, and roots only on the outside such as Rock Creeping Algae, and those that have deposits of calcareous matter such as Laver. In terms of internal structure, there are various forms, such as non-cellular types in which the entire protoplasm is connected without any horizontal septa throughout the body, and even among multicellular types, there are those with single or multiple nuclei within the cells. Most are small, measuring around 30 to 40 centimeters or less in body size, and there are few species that are over 1 meter in size.

[Moriaki Shinzaki]

Brown algae

Brown algae / [science] Phaeophyta The main pigments are chlorophyll a and c, and the body color is predominantly brown. All species are true multicellular, but the body shapes vary. There are branched types such as the sclerotinia with thin thread-like body branches, the mozuku species with slightly thick slimy body branches, and the sclerotia species with flat membranous body branches, the sea fan species with membranous leaves, the kelp species with thick belt-like leaves and stems, the wakame species with leaf-like leaves, and even the sargassum species with differentiated stems, leaves, and roots. There is a great deal of variation in body shape. The body size also varies, with small species ranging from a few millimeters to 30-40 centimeters, but most are large species that grow to over 1 meter, and some giant species that can reach tens of meters.

[Moriaki Shinzaki]

Red algae

Red algae / Rhodophyta The main pigments are chlorophyll a and phycobilin, but phycobilin contains a lot of phycoerythrin (red algae pigment), so the main body color is reddish red. In terms of body shape, there are branched types such as Igisu and Egonori with thin filamentous branches, Gracilaria species with long and thick thin cord-like branches, Hornwort species with leathery flat leaf-like body branches, and Kabanori, as well as soft thin-leaf-like Amanori, Tambanori with thick flat leaf pieces, and Tsurutsuru, which have leaf-like shapes. In addition, there are also species such as Gelidium species, Suginori, and Centipede, which have differentiation of main branches and branches and become somewhat tree-like, and there are many variations in body shape. Although the main color of the body is reddish red, there are also a variety of colors such as yellowish and greenish, and the same species often has different body colors. Most range in size from 30-40 centimetres to around 1 metre, with very few large species exceeding 1 metre.

Of the four plant divisions mentioned above, blue-green algae are tiny and have almost no utility value, so research on them has lagged behind, but the other three plant divisions include genera and species that have been useful to human life in various ways, such as for food since ancient times, so research on them has progressed from both a purely scientific and applied perspective. In particular, the edible value of seaweed has been reevaluated in recent years, and research on it has progressed further.

[Moriaki Shinzaki]

Differences between terrestrial and aquatic plants

In order to look at the morphological and ecological characteristics of seaweed, we will list the differences between terrestrial and aquatic plants.

(1) In terrestrial plants, the differentiation of stems, roots, and leaves is clear, and most have a rigid body structure that stands upright in the air, whereas in aquatic plants, the body structure is not differentiated, and most are uniformly soft, swaying with the movement of the water.

(2) Terrestrial plants are almost all green, but aquatic plants have a wide variety of body colors, from green to indigo, brown, and red.

(3) When the time comes for flowering, terrestrial plants produce beautiful flowers and seeds, but this is not the case with aquatic plants.

Next, we need to know the main differences between the ocean and land environments. These differences are as follows:

(1) The heat capacity of ocean water is greater than that of air, so the seasonal changes in water temperature are mild and not as severe as the changes in air temperature on land. Also, because warm and cold ocean currents have an impact over long distances, the horizontal (geographical) distribution, or the delineation of cold, warm, and warm zones, is quite different from that on land.

(2) At the ocean surface, there is a tidal phenomenon that fluctuates mainly with the revolution of the moon (lunar), and on the coast, the water level rises and falls due to high and low tides. In addition, as you go deeper into the ocean, not only does the sunlight get absorbed and scattered, decreasing the amount of light, but the wavelengths also decrease from the long wavelength range. In other words, in addition to changes in the amount of light (brightness and darkness) depending on the depth, there are also differences in the quality of light (color).

In addition, the up and down movement of the water surface on the coastline due to tides creates a difference between the intertidal zone, which is a land environment at low tide and an underwater environment at high tide, and the subtidal zone (deep tidal zone) below the low tide line.

[Moriaki Shinzaki]

Distribution and growth of seaweed

As mentioned above, the ocean has unique environmental conditions, so the distribution and growth patterns of seaweed are as follows:

(1) If the water temperature is divided into three regions, cold, warm, and warm, red algae grow equally in all regions, but green algae tend to grow more in warm seas and brown algae in cold seas. Also, since green algae do not have large species like brown algae such as kelp and sargassum, the seaweed vegetation and scenery are diverse in warm seas but are poor and lack the vegetation that can be called underwater forests, whereas cold seas have well-developed underwater forests and are lively. In other words, the situation is the opposite of that on land, where forests grow more lushly in hot regions such as the tropics.

(2) Due to changes in the amount and quality of light caused by tides and depth, the behavior of seaweed changes vertically even on the same coast.

The genera and species of seaweed that grow in the intertidal and subtidal zones are different, and there are also differences in their lifestyles. A distinctive feature is that intertidal algae are mostly small and annual, while subtidal algae are mostly large and perennial. Furthermore, annual algae in the intertidal zone undergo seasonal changes, flourishing in winter and spring and dying off in summer. This behavior, which can be described as "dying in summer and flourishing in winter and spring," is one of the differences from algae on land. Such seasonal changes are evident in both temperate and warm seas off the coast of Japan, but are not so evident in cold seas or on the coasts of Europe and the United States.

(3) The body colors of green, brown, and red algae are due to differences in the composition of pigments they contain. Therefore, there are differences in the amount and quality of light that seaweed uses to photosynthesize, and brown and red algae can photosynthesize even under weak light or wavelengths that would cause green algae to stop photosynthesis. As the depth of the ocean increases, the light becomes weaker and longer wavelengths are absorbed in succession from red to orange-yellow to green, so the maximum depth at which photosynthesis can occur is said to be around 200 meters. However, seaweed actually grows in depths of less than 50 meters, and is particularly abundant in depths of less than 20 meters. Within this depth range, green algae tend to grow in shallow areas, red algae in deep areas, and brown algae in the middle layer. Even in shallow areas, such as caves, green algae grow in bright areas near the entrance, while brown algae and red algae grow in dark areas in the back. One theory is that these differences in growth depth are due to a phenomenon in seaweed that is similar to the difference between sun-loving and shade-loving trees on land.Another theory is Engelmann's complementary color adaptation theory, which states that in shallow waters, red areas are present, so green algae, which are the complementary color, grow, and in deeper waters, green-blue areas remain, so red algae, which are the complementary color, grow.

[Moriaki Shinzaki]

Japanese people and seaweed

Japan is an island nation stretching from north to south, and its coasts are among the world's largest seaweed growing areas, making it the world's largest user of seaweed. Since the Pacific coast of Japan has had a wide variety of seaweed species and been abundant since prehistoric times, it is believed that seaweed was a significant food source until the agricultural era. The Manyoshu contains nearly 100 short and long poems that include seaweed. The word "tamamo," which often appears in Manyoshu poems, often refers to seaweed in general. Looking at documents such as the Manyoshu, it seems that even at the time when scientific knowledge was low, there was a distinction between "kusa" and "mo," or between "kusa" and "mo." The shape of the kanji character "mo" originates from the state of a plant body that is free to move in the water, but when read as "mo," it is used not only for algae as classified in the present taxonomy, but also for freshwater and marine seed plants, a practice that continues to this day. From these documents, looking at seaweeds alone, the genera and species with the name "mo" (mo) include akamoku, joromoku, and kormoha (an archaic word for tengusa), which were used for tree-like or similarly shaped plants. In contrast, even among large algae, the genera and species with broad, flattened leaves were given the name me (cloth, sea cloth), and words such as wakame, arame, and hirome (an archaic word for kombu) were used.

According to the Wamyōshō, 21 kinds of seaweed were recorded as edible during the Heian period, including wakame (seaweed) and arame (seaweed). From the Kamakura period onwards, seaweed began to be used in processed products, especially sweets. One example was storing kelp for 2-5 years, treating the softened kelp with vinegar, cutting it into strips, tying them together and roasting them over a fire.

In the Edo period, seaweed began to be used not only in cooking but also as a soup stock. This was because kelp began to be available in large quantities on the market during this period. Also during the Edo period, each feudal domain encouraged industry in an effort to enrich their finances. As a result, processing industries using marine products as raw materials also flourished. Various types of seaweed from Ise, wakame from Mikawa, and sea somen noodles from Wakasa all date back to this period. In particular, it was groundbreaking when Asakusa nori became a nationally distributed product following the development of cultivation techniques.

In this way, the ancient Japanese custom of eating many different kinds of seaweed can be said to have continued unabated to the present day.

[Moriaki Shinzaki]

Food Value

The use of seaweed, especially in the diet, is well developed in Japan. Because the carbohydrates contained in seaweed often differ in chemical structure and physical properties from those found in terrestrial plants, the consumption of seaweed was not a custom in Western countries, with only a few exceptions, until recently. However, as a result of accumulated research into seaweed components, it has been found to contain a high content of minerals and vitamins, such as calcium, potassium, iodine, and vitamins A and C. Seaweed has been reassessed as a health food, particularly for the elderly, rather than as a source of calories, and the consumption of seaweed is becoming more widespread in Europe and the United States. In response to this, there is a movement in the United States to call it "sea vegetables."

[Moriaki Shinzaki]

"Aquatic Botany" by Saburo Shigeta et al. (1963, Koseisha Kouseikaku)" ▽ "Seaweed" by Akira Miyashita (1974, Hosei University Press)" ▽ "Colored Illustrated Guide to Japanese Seaweed" by Muneyoshi Segawa, supplemented by Tadao Yoshida (1977, Hoikusha)" ▽ "The Story of Seaweed" by Moritoshi Shinzaki and Teruko Shinzaki (1979, Tokai University Press)

[Reference item] | Asakusa nori | Algae

Major types of brown algae (1) [specimen illustrations]
※Instructor: Makoto Yoshizaki © Fukuko Aoki ">

Major types of brown algae (1) [specimen illustrations]

Major types of brown algae (2) [specimen drawings and photographs]
※Instructors: Makoto Yoshizaki ©Fukuko Aoki ©Kanezo Otawa ©Shogakukan ">

Major types of brown algae (2) [specimen illustrations and labels]

Major types of brown algae (3) [specimen illustrations]
※Instructor: Makoto Yoshizaki ©Kenzo Otawa ">

Major types of brown algae (3) [specimen illustrations]

Major types of red algae (1) [specimen drawings and photographs]
※Instructor: Makoto Yoshizaki ©Kanezo Otawa ©Shogakukan ">

Major types of red algae (1) [specimen illustrations and labels]

Major types of red algae (2) [specimen drawings and photographs]
※Instructor: Makoto Yoshizaki ©Kanezo Otawa ©Shogakukan ">

Major types of red algae (2) [specimen illustrations and labels]

Major types of green algae (specimen illustrations)
※Instructors: Makoto Yoshizaki ©Tadaaki Ohkata ©Shogakukan ">

Major types of green algae (specimen illustrations)

Algae life cycle (Ulva)
© Shigeru Yoshizaki

Algae life cycle (Ulva)

Algae life cycle (Kelp)
© Shigeru Yoshizaki

Algae life cycle (Kelp)

Algae life cycle (Algae)
© Shigeru Yoshizaki

Algae life cycle (Algae)

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

海に生育する植物の分類群には緑色植物（種子植物、緑藻植物、プラシノ藻植物など）、ミドリムシ植物、黄色植物（褐藻植物、珪藻(けいそう)植物、ラフィド藻植物など）、ハプト植物、渦鞭毛(べんもう)植物、クリプト植物、紅藻植物、プロクロロン植物、藍藻(らんそう)植物などがある。しかし一般的に海藻というと、体が大形である緑藻植物、褐藻植物、紅藻植物、藍藻植物をさすことが多い。ここでは、主としてこの4群について解説する。

［新崎盛敏］

藍藻植物

blue-green algae／【学】Cyanophyta　主要含有色素はクロロフィルaとフィコビリンで、体色は藍青色あるいは紫紅色。藍藻植物は本来、単細胞藻で顕微鏡的微小体であるが、これらが多数集まってつくる群体は肉眼視大になる。海藻として扱われるのはこの群体で、藍青色となり、4センチメートルくらいの毛状体として生育する。日本各地の海岸の岩や岩壁、杭上(こうじょう)などの満潮線付近の上層帯に、夏のころ繁茂する。分類はむずかしいが、クダモ属Lyngbya、ヒゲモ属Rivularia、ユレモ属Oscillatoria、イトヒゲモ属Calothrixなどの諸属が多い。元来これらの藍藻類は暖地性であるため、繁茂期間も分布域もやや限られていて、目だたなかったが、海水の汚濁や富栄養化が広まるにつれて生育量が増え、繁茂期間も長くなるなどの現象がおこり、現在では日本各地で普遍的にみられるようになった。

［新崎盛敏］

緑藻植物

green algae／【学】Chlorophyta　主要含有色素はクロロフィルaとbで、陸上植物に似ており、体色は緑色が主調になる。体形には、アオサ、アオノリ、ヒトエグサのように柔らかい膜質の扁平(へんぺい)葉あるいは管状葉形のもの、シオグサ、ハネモなどのような細い体枝の分岐形のもの、あるいはミルのような太い体枝の分岐形のものがある。また、イワヅタ類のように外見だけは葉、茎、根の分化があるもの、カサノリ類のように石灰質を沈着するものもある。内部構造では、体中に横隔壁がなくて全原形質がつながっている非細胞型のもの、また、多細胞型のなかにも細胞内核数が単核のもの、多核のものなど、いろいろな形態をとる。体の大きさは、30～40センチメートル内外からそれ以下の小形が多く、1メートル以上の種は少ない。

［新崎盛敏］

褐藻植物

brown algae／【学】Phaeophyta　主要色素はクロロフィルaとcで、体色は褐色が主調になる。すべての種が真正多細胞型であるが、体形はさまざまである。細糸状の体枝をもつシオミドロ、やや太めのぬるぬるとした体枝をもつモズク類、扁平膜質の体枝をもつアミジグサ類などのような分岐形もあれば、全体が膜質葉状のウミウチワ類、肉厚の帯状葉片と茎とがあるコンブ、ワカメなどのような葉状形、さらにはホンダワラ類のように茎、葉、根の分化がある樹状形などがあり、体形の変化が多い。体の大きさもさまざまで、数ミリメートルから30～40センチメートルくらいの小形種もあるが、多いのは1メートル以上になる大形種で、なかには数十メートルに達する巨大種がある。

［新崎盛敏］

紅藻植物

red algae／【学】Rhodophyta　主要色素はクロロフィルaとフィコビリンであるが、フィコビリンではフィコエリスリン（紅藻素）の含有が多いので、体色は紅赤色が主調になる。体形では、細糸状体枝をもつイギス、エゴノリ、長くて太めの細紐(ほそひも)状体枝をもつオゴノリ類、また革質扁平葉状の体枝をもつツノマタ類、カバノリなどのような分岐形のほか、柔らかい薄膜葉状のアマノリ類、肉厚の扁平葉片のタンバノリ、ツルツルなどのような葉状形がある。さらに、テングサ類、スギノリ、ムカデノリなどのように、主枝、分枝の分化があってやや樹状形になるものなどもあり、体形の変化が多い。体色でも、紅赤色が主調とはなるが、黄みがかるもの、緑みがかるものなどと多彩で、同一種でも体色の違う場合が多い。大きさは、30～40センチメートルから1メートル前後のものが大部分で、1メートルを超える大形種はきわめて少ない。

　これまで述べた4植物門のなかで、藍藻植物は体形が微小で、利用価値もほとんどないため、研究面でも遅れているが、他の3植物門については、古代から食用その他の面で、なにかと人間生活に役だってきた属種が含まれるので、純科学面ないしは応用面からの諸研究が進んでいる。とくに近年は、海藻の食用価値が見直されており、研究も一段と進展している。

［新崎盛敏］

陸生植物と水生植物の相違

海藻の形態的、生態的な特徴等をみるために、陸生と水生の植物間での相違をあげてみる。

(1)陸生植物では、茎、根、葉の分化が明瞭(めいりょう)で、体構造は堅固、空中に直立しているものが多いのに対して、水生植物では、体制に分化がなく、一様に柔らかく、水の動きのままに揺れ動くものが多い。

(2)陸生植物は、緑1色といってよいほどであるが、水生植物では、緑、藍、褐、紅と体色が多彩で、変化に富む。

(3)陸生植物では、開花時期がくると美しい花をつけ、種子をつくるが、水生植物には、このようなものがみられない。

　次に海と陸との環境上の主要な相違点を知る必要がある。その相違点とは以下のようなものである。

(1)海水の熱容量は、空気のそれよりも大きいため、水温の季節変化は温和で、陸上での気温変化ほどの厳しさがない。また、暖・寒の海流が遠隔の所までその影響を及ぼすので、水平（地理的）分布、ないしは寒・温・暖の地帯の線引きは、陸上の場合とはかなり違う。

(2)海面では、主として月（太陰）の公転に伴って変動する潮汐(ちょうせき)現象があり、海岸では満潮、干潮による水面の上下変動がある。そのほかにも、海中深くなるにつれて太陽光線は吸収、散乱され、光量が減少していくだけではなく、波長も長波長域から順次減少していく。すなわち、深度によって光量（明暗）の変化以外に光質（色調）の相違もおこるわけである。

　また、潮汐による海岸線での水面の上下運動では、干潮時には陸上環境下になり、満潮時には海中環境下になる潮間帯と、干潮線以下の潮下帯（潮深帯）との相違がおこる。

［新崎盛敏］

海藻の分布と生育

前述のように、海には特有の環境条件があるため、海藻の分布、生育の様相は次のようになる。

(1)水温の相違で、寒海域、温海域、暖海域に3区分すると、紅藻は全域に同等に生育するが、緑藻は暖海に、褐藻は寒海により多く生育するという傾向がある。そして、緑藻には、褐藻でのコンブ類、ホンダワラ類のような大形種がないので、海藻植生とその景観では、暖海域は多彩ではあるが、海中林とよべる植相がなくて貧相なのに対し、寒海域は海中林がよく発達してにぎにぎしい。つまり、陸上では熱帯などの高温地域に、より森林が繁茂するのとは逆の様相を呈するわけである。

(2)潮汐と深さに伴う光量、光質の変化によって、同じ海岸でも、海藻の生き方には垂直的な変化がみられる。

　潮間帯と潮下帯では、生育する海藻の属種も異なり、その生き方にも相違がみられる。特徴的なことは、潮間帯藻は小形種で一年生体がほとんどであるのに対し、潮下帯藻は大形種で多年生体が多いということである。そして、潮間帯の一年生藻は、冬、春に繁茂して夏季に死滅するという季節変化をもつ。この「夏枯れ、冬春繁茂」ともいえる様相は、陸上のそれとの相違の一つである。このような季節変化は、日本沿岸でも温・暖両海域で著明であり、寒海域や欧米の海岸などではそれほど著明ではない。

(3)緑藻、褐藻、紅藻の体色は、含有色素類組成の相違に起因する。したがって、海藻がこれらを使って光合成する際の光量、光質にも違いがあり、褐藻と紅藻は、緑藻が光合成を止めるような弱光下や波長域でも光合成を行うことができる。海の深度が増すにしたがい弱光となり、また、赤、橙黄(とうこう)、緑と順次長波長域が吸収されていくので、光合成を行える深度限界は水深200メートル前後とされる。しかし、実際に海藻類が生育しているのは、50メートル以浅、とくに20メートル以浅に多産する。こうした深度範囲のなかで、緑藻は浅所に、紅藻は深所に、褐藻は中間層に多く生育するという傾向があり、また、浅所でも洞穴などの場合、入口近くの明所では緑藻が、奥の暗所では褐藻、紅藻が多くなる。このような生育深度での相違に対し、陸上での陽樹、陰樹の相違に似たような現象が海藻にもあるためとする説もあれば、浅所では赤色域があるので、その補色である緑藻が生育し、深所では緑青域が残るから、その補色である紅藻が生育するという「エンゲルマンの補色適応説」もある。

［新崎盛敏］

日本人と海藻

南北に長く延びた島国である日本の周縁海岸は、世界有数の海藻類生育域であり、日本は世界一の海藻利用国である。日本の太平洋沿岸は、先史時代から海藻の種類が多く、豊富に得られたことから、農耕時代を迎えるまでは、海藻がかなり重要な食糧であったと想像される。『万葉集』には、海藻を詠み込んだ短歌や長歌が100首近く記録されている。万葉の歌にしばしば出てくる「玉藻(たまも)」とは、海藻全般をさす場合が多い。『万葉集』などの文献をみると、科学的知識の低かった当時でも、草と藻、または「クサ」と「モ」の使い分けはあったようである。漢字の藻の字形は、水に身を任せて動く植物体の状態に起源するが、「モ」と訓で読む場合には、いまの分類学上の藻類に属するものだけではなく、淡水産、海産の種子植物にも使われ、それが今日にも及んでいる。こうした文献から、海藻内だけで、モ（モク）の名がつく属種をみると、アカモク、ジョロモク、コルモハ（テングサの古語）などがあり、樹形あるいはそれに近い体形のものに使われていた。これに対して、大形藻でも、幅広い扁平葉片をもつ属種にはメ（布、海布）があてられ、ワカメ、アラメ、ヒロメ（コンブの古語）などの語が用いられている。

　平安時代に食用とされた海藻は、『和名抄(わみょうしょう)』によると、海藻(わかめ)、滑海藻(あらめ)など21種が記録されている。鎌倉時代以後になると、海藻加工品、とくに菓子として利用されるようになった。コンブを2～5年間保存し、軟らかく変化したものを酢で処理し、短冊に切り、結んでから火にあぶって食べたのもその一例である。

　江戸時代になると、海藻は料理としての利用のほかに、だし汁としても用いられるようになった。この時代になって、コンブが大量に市場に出回るようになったためである。また、江戸時代には、各藩がこぞって産業を奨励し、藩の財政を豊かにしようとした。このため、水産物を原料とする加工業も栄えた。伊勢(いせ)の海藻各種、三河のわかめ、若狭(わかさ)の海そうめんなどは、この時代から始まったものである。とくに、浅草海苔(のり)が、養殖技術の開発とともに全国的な流通商品となったことは、画期的なことであった。

　このように古代から多種類の海藻を食用とする日本人の風習は、現代に至るまで衰えることなく連綿として続いているということができる。

［新崎盛敏］

食品価値

海藻の利用とくに食生活への利用は日本でよく発達している。海藻に含まれる炭水化物は、化学構造また物理的性状が陸上植物中の炭水化物とは違う場合が多いため、欧米諸国では、ごく一部の例外を除き、近年まで海藻食の習慣はなかった。しかし、海藻成分についての研究が積み重ねられた結果、カルシウム、カリ、ヨード、ビタミンAやCなど、ミネラルとビタミン類の含有量が多いことがわかり、カロリー源食品としてではなくて保健食品とくに熟年層への食品価値が見直され、欧米でも海藻食が普及しようとしている。それに応じてアメリカでは海菜sea vegetablesとよぼうとの動きもある。

［新崎盛敏］

『殖田三郎他著『水産植物学』（1963・恒星社厚生閣）』▽『宮下章著『海藻』（1974・法政大学出版局）』▽『瀬川宗吉著、吉田忠生補遺『原色日本海藻図鑑』（1977・保育社）』▽『新崎盛敏・新崎輝子著『海藻のはなし』（1979・東海大学出版会）』

[参照項目] | アサクサノリ | 藻類

褐藻植物のおもな種類(1)〔標本画〕

褐藻植物のおもな種類(2)〔標本画・標…

褐藻植物のおもな種類(3)〔標本画〕

紅藻植物のおもな種類(1)〔標本画・標…

紅藻植物のおもな種類(2)〔標本画・標…

緑藻植物のおもな種類〔標本画〕

藻類の生活環（アオサ）

藻類の生活環（コンブ）

藻類の生活環（マクサ）