Part A | 6.1
66 Part A Marine Flora and Fauna
up to lower penetration of light effective for the realization of photosynthesis of algae (up to 200 m deep).
Those that live in water can be planktonic (microalgae) or benthic (macroalgae). The former are small and
remain suspended in water (microscopic), whereas the
latter remain fixed to a substrate (usually rock), are
larger in size (macroscopic), and may reach 50 m in
length [6.1].
6.1.1 Role of Algae in Nature
Algae are primary producers, i. e., they are able to
produce oxygen and organic compounds that serve
as food for other living beings, through the process
of photosynthesis, using sunlight, atmospheric CO 2 ,
and inorganic substances present in water. Algae are,
in fact, fundamental to food chains of all aquatic
ecosystems.
6.1.2 Main Taxonomic Groups
of Benthic Marine Algae
The coloration of seaweed is the visible expression
of the combination of different cellular pigments.
Thus, the phyla and classes of macroalgae are essentially defined in practice by their particular pigment
composition.
Macroalgae are aquatic photosynthetic organisms
belonging to the Domain Eukarya and the Kingdoms
Plantae (green and red algae) and Chromista (brown
algae). Although classification systems vary over time
and according to the authors, it is generally accepted to
consider that
1. The green algae are included in the Phylum
Chlorophyta; their pigmentation is identical to
that of terrestrial plants (chlorophyll a, b, and
carotenoids);
2. The red algae belong to the phylum Rhodophyta,
their photosynthetic pigments are chlorophyll
a, phycobilins (R-phycocyanin and R-phycoerythrin), and carotenoids (ˇ-carotene, lutein, and
zeaxanthin);
3. The brown algae are included in the phylum Ochrophyta (or Heterokontophyta), class
Phaeophyceae; their pigments are the chlorophylls a, c, and carotenoids, dominated by fucoxanthin, responsible for the brownish color
[6.1, 2].
6.1.3 Marine Algae Morphology
The diversity of algae is extraordinary; one can find
a multitude of morphological types according to their
complexity, structure, and environmental adaptations.
Macroalgae show a complex degree of morphological
organization, with laminar, cylindrical, tubular, or crustose thalli.
6.1.4 Importance of Algae for Mankind
Today, seaweed is used in many countries for very
different purposes: directly as food, phycocolloids extraction, extraction of compounds with antiviral, antibacterial, or antitumor activity and as biofertilizers.
About four million tonnes of seaweed are harvested
annually worldwide. The major producers are China
and Japan, followed by America and Norway. France
used to import Japanese seaweed in the 1970s but 10
years later it went on to produce algae for food and biological products users. Contrary to what happens in
East Asia, the West is more interested in thickeners and
gelling properties of hydrocolloids extracted from seaweeds: carrageenan, agar, and alginate (E407, E406,
and E400, respectively) [6.3, 4].
6.1.5 Historical Overview
of Algae Use on Health Treatments
Historically, the algae have been used by coastal communities to prepare home medicines to treat various
health problems. Such applications are the product of
the empirical knowledge of many generations and, in
most cases, their mechanisms are unknown. However,
the current research, undertaken in order to analyze the
components and causes which affect the proper functioning of our body, are already giving their first fruits.
So, we know, for example, that the good results obtained with the use of Kelp (Laminaria spp.) in the
treatment of goiter are due to the fact that the origin
of this disease is a diet low in iodine, chemical element
present in significant quantities in brown algae [6.3].
Green algae have been used as anthelmintics, astringent, and to treat gout. Brown algae are used in
the treatment of rheumatic processes, arteriosclerosis,
menstrual disorders, hypertension, gastric ulcers, goiter, skin diseases, syphilis, and as an anticoagulant. Red
algae are used as anticoagulants, anthelmintics, and in
treating gastritis and diarrhea [6.3, 5].
66 Part A Marine Flora and Fauna
up to lower penetration of light effective for the realization of photosynthesis of algae (up to 200 m deep).
Those that live in water can be planktonic (microalgae) or benthic (macroalgae). The former are small and
remain suspended in water (microscopic), whereas the
latter remain fixed to a substrate (usually rock), are
larger in size (macroscopic), and may reach 50 m in
length [6.1].
6.1.1 Role of Algae in Nature
Algae are primary producers, i. e., they are able to
produce oxygen and organic compounds that serve
as food for other living beings, through the process
of photosynthesis, using sunlight, atmospheric CO 2 ,
and inorganic substances present in water. Algae are,
in fact, fundamental to food chains of all aquatic
ecosystems.
6.1.2 Main Taxonomic Groups
of Benthic Marine Algae
The coloration of seaweed is the visible expression
of the combination of different cellular pigments.
Thus, the phyla and classes of macroalgae are essentially defined in practice by their particular pigment
composition.
Macroalgae are aquatic photosynthetic organisms
belonging to the Domain Eukarya and the Kingdoms
Plantae (green and red algae) and Chromista (brown
algae). Although classification systems vary over time
and according to the authors, it is generally accepted to
consider that
1. The green algae are included in the Phylum
Chlorophyta; their pigmentation is identical to
that of terrestrial plants (chlorophyll a, b, and
carotenoids);
2. The red algae belong to the phylum Rhodophyta,
their photosynthetic pigments are chlorophyll
a, phycobilins (R-phycocyanin and R-phycoerythrin), and carotenoids (ˇ-carotene, lutein, and
zeaxanthin);
3. The brown algae are included in the phylum Ochrophyta (or Heterokontophyta), class
Phaeophyceae; their pigments are the chlorophylls a, c, and carotenoids, dominated by fucoxanthin, responsible for the brownish color
[6.1, 2].
6.1.3 Marine Algae Morphology
The diversity of algae is extraordinary; one can find
a multitude of morphological types according to their
complexity, structure, and environmental adaptations.
Macroalgae show a complex degree of morphological
organization, with laminar, cylindrical, tubular, or crustose thalli.
6.1.4 Importance of Algae for Mankind
Today, seaweed is used in many countries for very
different purposes: directly as food, phycocolloids extraction, extraction of compounds with antiviral, antibacterial, or antitumor activity and as biofertilizers.
About four million tonnes of seaweed are harvested
annually worldwide. The major producers are China
and Japan, followed by America and Norway. France
used to import Japanese seaweed in the 1970s but 10
years later it went on to produce algae for food and biological products users. Contrary to what happens in
East Asia, the West is more interested in thickeners and
gelling properties of hydrocolloids extracted from seaweeds: carrageenan, agar, and alginate (E407, E406,
and E400, respectively) [6.3, 4].
6.1.5 Historical Overview
of Algae Use on Health Treatments
Historically, the algae have been used by coastal communities to prepare home medicines to treat various
health problems. Such applications are the product of
the empirical knowledge of many generations and, in
most cases, their mechanisms are unknown. However,
the current research, undertaken in order to analyze the
components and causes which affect the proper functioning of our body, are already giving their first fruits.
So, we know, for example, that the good results obtained with the use of Kelp (Laminaria spp.) in the
treatment of goiter are due to the fact that the origin
of this disease is a diet low in iodine, chemical element
present in significant quantities in brown algae [6.3].
Green algae have been used as anthelmintics, astringent, and to treat gout. Brown algae are used in
the treatment of rheumatic processes, arteriosclerosis,
menstrual disorders, hypertension, gastric ulcers, goiter, skin diseases, syphilis, and as an anticoagulant. Red
algae are used as anticoagulants, anthelmintics, and in
treating gastritis and diarrhea [6.3, 5].