Algae and Their Characteristics, varieties Of Algae, ecological Relationships, determinants Limiting The performance Of Algae


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Algae (singular: alga) are photosynthetic, eukaryotic organisms that carry out not develop multicellular sex organs. Algae have the right to be unicellular, or they might be large, multicellular organisms. Algae can occur in salt or fresh waters, or ~ above the surface of moist soil or rocks. The multicellular birds develop devoted tissues, however they lack the true stems, leaves, or root of the more complex, greater plants.

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The algae space not a uniform team of organisms. They in reality consist the seven divisions of distantly related organisms. This are considered together much more as a issue of person convenience, 보다 as a reflection of their ordered, biological, or evolutionary relationships. Therefore, the ax "algae" is a common one, rather than a word the connotes a specific, scientific meaning.


Euglenophyta (euglenoids)

The Euglenophyta or euglenoids space 800 species of unicellular, protozoan-like algae, many of which take place in fresh waters. The euglenoids lack a true cell wall, and also are bounded by a proteinaceous cell covering recognized as a pellicle. Euglenophytes have actually one to three flagellae for locomotion, and they keep carbohydrate reserves as paramylon. The main photosynthetic colours of euglenophytes space chlorophylls a and b, while their accessory pigments space carotenoids and xanthophylls.

Most euglenoids have chloroplasts, and also are photosynthetic. Part species, however, room heterotrophic, and feed on organic material suspended in the water. Even the photosynthetic species, however, are capable of surviving for part time if retained in the dark, as lengthy as they are "fed" with an ideal organic materials.


Chrysophyta (golden-brown algae)

The Chrysophyta room the golden-brown algae and also diatoms, which dong account because that 1,100 and 40,000-100,000 types of uncellular cells algae. These algae take place in both marine and also fresh waters, return most species are marine. The cell walls of golden-brown algae and diatoms space made the cellulose and also pectic materials, a kind of hemicellulose. In the diatoms especially, the cell wall is heavily impregnated through silica and also is thus quite rigid and also resistant come decay. These algae store power as a carbohydrate referred to as leucosin, and likewise in oil droplets. The golden-brown algae achieve locomotion utilizing one to 2 flagellae. The photosynthetic pigments of these algae space chlorophylls a and also c, and also the accessory pigments are carotenoids and also xanthophylls, consisting of a committed pigment recognized as fucoxanthin.

Communities of cat birds (class Bacillariophyceae) have the right to be very diverse, with much more than 500 species commonly tape-recorded from the phytoplankton, periphyton, and also surface muds of individual ponds and also lakes. Cat birds have double shells, or frustules, that space largely constructed of silica (SiO2), the two halves of which (called valves) fit together choose a pillbox. Diatom types are differentiated on the communication of the shape of their frustules, and also the exquisite markings on the surface ar of this structures.

The golden-brown algae (class Chrysophyceae) are much less diverse than the diatoms. Some varieties of golden-brown algae lack cell walls, while others have pectin-rich walls. Golden-brown birds are specifically important in open waters of the oceans, where they may overcome the productivity and biomass of the specifically tiny dimension fractions of the phytoplankton. This are known as the nanoplankton, consists of cells smaller than around 0.05 mm in diameter.


Pyrrophyta (fire algae)

The Pyrrophyta space the fire algae, including the dinoflagellates, which with each other account because that 1,100 types of uncellular cells algae. Most of these species occur in naval ecosystems, but some space in new waters. The dinoflagellates have actually cell walls constructed of cellulose, and have 2 flagellae. These algae store energy as starch. The photosynthesis pigments of the Pyrrophyta room chlorophylls a and c, and the accessory pigments space carotenoids and xanthophyll, consisting of fucoxanthin.

Some varieties of dinoflagellates deserve to temporarily accomplish a an excellent abundance, as events that are generally known together "red tides" because of the resulting color of the water. Red tides deserve to be toxicity to maritime animals, since of the existence of poisonous chemicals that room synthesized by the dinoflagellates. Some types of dinoflagellates build a bioluminescence, which deserve to be plainly seen at night, and also may cause the surface ar of the ocean to look as if it were aflame.


Chlorophyta (green algae)

The Chlorophyta or environment-friendly algae consist of about 7,000 species, most of which happen in fresh water, although some others space marine. Most eco-friendly algae are microscopic, but a couple of species, such together those in the genus Cladophora, are multicellular and macroscopic. The cell wall surfaces of environment-friendly algae room mostly created of cellulose, v some incorporation of hemicellulose, and also calcium carbonate in part species. The food reserves of eco-friendly algae space starch, and their cells deserve to have 2 or an ext organelles known as flagella, i beg your pardon are used in a whiplike fashion for locomotion. The photosynthetic pigments of green algae space chlorophylls a and also b, and also their accessory pigments room carotenoids and also xanthophylls.

Some typical examples of environment-friendly algae encompass the imreparable cells genera Chlamydomonas and Chlorella, which have varieties dispersed in a wide variety of habitats. More complicated green algae include Gonium, which develops small, spherical nests of 4 to 32 cells, and Volvox, which creates much larger, hollow-spherical nests consisting of tens of countless cells. Some other colonial varieties are much larger, for example, Cladophora, a filamentous species that can be numerous meters long, and Codium magnum, which deserve to be as lengthy as 26 ft (8 m).

The life cycle of Chlorococcum, a green alga. Illustration by Hans & Cassidy. Courtesy of Gale Group.

The stoneworts (class Charophyceae) are a very distinctive group of green algae the are periodically treated together a separate department (the Charophyta). These birds can take place in new or brackish waters, and also they have actually cell wall surfaces that contain huge concentrations that calcium carbonate. Charophytes have relatively complicated growth forms, through whorls the "branches" developing at their tissue nodes. Charophytes are likewise the just algae that develop multicellular sex organs, return these space not equivalent to those the the higher plants.


Rhodophyta (red algae)

The Rhodophyta or red algae are 4,000 species of mostly marine algae, which room most varied in tropic waters. Varieties of red algae range from microscopic to macroscopic in size. The larger species typically flourish attached come a difficult substrate, or they occur as epiphytes on other algae. The cell walls of red birds are built of cellulose and also polysaccharides, such together agar and also carrageenin. These algae absence flagellae, and they store power as a dedicated polysaccharide well-known as floridean starch. The photosynthetic pigments of red algae space chlorophylls a and d, and also their accessory pigments are carotenoids, xanthophyll, and phycobilins.

Some examples of red algae include filamentous species such together Pleonosporum spp., so-called coralline birds such together Porolithon spp., which become heavily encrusted v calcium carbonate and also contribute greatly to the structure of tropical reefs, and thalloid species, such together the economically important ireland moss ( Chondrus crispus).


Paeophyta (brown algae)

The Paeophyta or brown birds number about 1,500 species, almost every one of which happen in marine environments. These seaweeds are especially abundant in cool waters. Varieties of brown algae space macroscopic in size, including the huge kelps that have the right to routinely achieve lengths of 10s of meters. Brown algae have actually cell walls built of cellulose and polysaccharides recognized as alginic acids. Some brown birds have fairly complex, identified tissues, including a holdfast that secures the organism to its substrate, air bladders to assist with buoyancy, a sustaining stalk or stipe, large blades that administer the major surface for nutrient exchange and photosynthesis, and spore-producing, reproductive tissues. The specialized, reproductive cell of brown birds are burned into the water and are motile, using two flagella to attain locomotion. The food make reservation of this algae room carbohydrate polymers well-known as laminarin. Your photosynthetic pigments room chlorophylls a and c, while the accessory pigments are carotenoids and xanthophylls, consisting of fucoxanthin, a brown-colored colors that offers these algae their properties dark color.

Some examples of brown algae encompass the sargassum weed (Sargassum spp.), i beg your pardon dominates the extensive, floating ecosystem in the mid-Atlantic gyre known as the Sargasso Sea. Most brown seaweeds, however, happen on hard-bottom, coastal substrates, especially in cooler waters. Examples of these include the rockweeds (Fucus spp. And Ascophyllum spp.), the kelps (Laminaria spp.), and also the gigantic kelps (Macrocystis spp. And Nereocystis spp.). The giant kelps are by much the largest of the algae, afford a length as good as 328 ft (100 m).

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Xanthophyta (yellow-green algae)

The Xanthophyta or yellow-green algae space 450 types that primarily happen in fresh waters. They space unicellular or small-colonial algae, v cell wall surfaces made that cellulose and also pectic compounds, and sometimes containing silica. The yellow-green algae keep carbohydrate together leucosin, and they can have two or an ext flagellae for locomotion. The major photosynthetic colours of yellow-green algae is chlorophyll a, and also the accessory pigments space carotenoids and xanthophyll.


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