Difference Between Red Algae and Brown Algae

Key Difference – RedAlgae vs Brown Algae

Algaeare large polyphyletic, photosynthetic organisms that contain a diverse group of species. They range from unicellular microalgae genera such asChlorellato multicellular forms such as giant kelp and brown algae. They are mostly aquatic andautotrophicin nature. They lackstomata,xylem, and phloemthat are found in the land plants. The most complex marine algae areseaweeds. On the other hand, the most complex freshwater form is Charophyta which is a group ofgreen algae. They havechlorophyllas their primary photosynthetic pigment. And they lack sterile covering of cells around their reproductive cells. Red algae are one of the oldesteukaryoticalgae. They are multicellular, mostly marine algae which included a notable proportion of seaweeds. Only about 5 % of red algae occur in fresh water. Brown algae are another group of algae which are large multicellular, eukaryotic, marine algae that grow mainly in the cold water of Northern Hemisphere. Many types of seaweed are coming under brown algae. Thekey differencebetween Red Algae and Brown Algae is that, in red algae, unicellular forms are present while in brown algae, unicellular forms are completely absent.

CONTENTS

1.Overview and Key Difference
2.What is Red Algae
3.What is Brown Algae
4.Similarities Between Red Algae and Brown Algae
5.Side by Side Comparison – Red Algae vs Brown Algae in Tabular Form
6.Summary

What are Red Algae?

Red algae are defined as eukaryotic, multicellular, marine algae which are categorized under the divisionRhodophyta. There are around 6500 to 10000 species of red algae are already found and they include some known seaweeds and 160 species of freshwater forms (5% of fresh water forms). The red color of red algae is due to the pigment phycobiliproteins (phycobilin). And also they contain some other pigments such as phycoerythrin and phycocyanin. Sometimes they reflect blue color too.

Red algae range from unicellular microscopic forms to multicellular large fleshy forms. They are found in all regions of the world. They normally grow attached to hard surfaces.Herbivoressuch as fish, crustaceans, worms, and gastropods are grazing red algae. Red algae have the most complex sexual life cycle among all algae. The female sex organ is known as ‘carpogonium’ that has a uninucleate region which serves as an egg. Red algae also possess a projection called as ‘tricogyne’. The non-motile male gametes (spermatia) are produced by the male sex organ known ‘spermatangia. Some red algae are important foods such as laver, dulse etc.

“Irish mosh” made up of red algae is used as a gelatin substitute in puddings, toothpaste, and ice creams. The gelatin-like substance that is prepared by the red algae species likeGracilariaandGellidium, is an important component of bacterial and fungal culture media.

What are Brown Algae?

The brown algae are defined as large, multicellular, eukaryotic marine algae that are categorized under the divisionChromophyta. Brown algae come under the classPhaeophyceae. They may grow up to 50 m in length. They are commonly found in cold waters along the continental coasts. Their species color varies from dark brown to olive green depending on the pigment proportion of brown pigment (fucoxanthin) to green pigment (chlorophyll). Brown algae range from small filamentousepiphytessuch asEctocarpus to large giant kelp such asLaminaria(100 m in length). Some brown algae are attached to rocky coasts in the temperate zones (eg:Fucus,Ascophyllum) or they float freely (eg:Sargassum). They reproduce by bothasexual and sexual reproduction. Bothzoospores(motile) and gametes have two unequalflagella.

Brown algae are major sources ofiodine, potash, and algin (colloidal gel). The algin is used as a stabilizer in the ice cream industry. Some species are used as fertilizers and some are consumed as vegetables (Laminaria) especially in the East Asian region.

What are the Similarities Between Red Algae and Brown Algae?

• Both are eukaryotic algae.
• Both contain marine algae.
• Both have multicellular species.
• Both can be seen in the coastal area and attached to hard surfaces.

的区别是什么en Red Algae and Brown Algae?

Red Algea vs Brown Algae
Red algae are defined as eukaryotic, multicellular, marine algae which are categorized under the division of Rhodophyta.	The brown algae are defined as large, multicellular, eukaryotic marine algae which are categorized under the division of Chromophyta.
Class
Red algae are categorized under the class of “Rhodophyceae”.	Brown algae are categorized under the class of “Phaeophyceae”.
Photosynthesis Pigments
Red algae have photosynthetic pigments such as phycobilin, phycoerythrin, and phycocyanin.	Brown algae have photosynthetic pigments such as fucoxanthin, chlorophyll.
Reserved Food Material
In Red algae, the reserved food material is Floridean starch.	In Brown algae, the reserved food materials are Laminarin or Mannitol.
Cell Wall Composition
In Red algae, the cell wall contains phycocolloid agar and carrageenan.	In Brown algae, the cell wall contains cellulose and the phycocolloid alginic acid (alginate).
Unicellular Forms
Unicellular forms are present in the Red algae.	Unicellular forms are completely absent in brown algae.

Summary – RedAlgae vs Brown Algae

Algae are the most complex form of eukaryotic organisms. They also have prokaryoticcyanobacteria(blue-green algae). There are unicellular and multicellular forms of algae. Algae live in the marine coastal environment as well as in fresh water. Algae are large polyphyletic, photosynthetic organisms. They have chlorophyll as their primary photosynthetic pigment. They lack stomata, xylem, and phloem that are found in the higher plants. Red algae are eukaryotic, multicellular, marine algae which included some of the seaweeds. Red algae are also found in fresh water. Brown algae are large multicellular, eukaryotic, marine algae types that grow mainly in Northern Hemisphere cold water. This is the difference between red algae and brown algae.

Download the PDF Version of Red Algae vs Brown Algae

您可以下载本文的PDF版本和use it for offline purposes as per citation note. Please download PDF version hereDifference Between Red Algae and Brown Algae

Reference:

1.The Editors of Encyclopædia Britannica. “Red algae.” Encyclopædia Britannica, Encyclopædia Britannica, inc., 3 Oct. 2016.Available here

2.The Editors of Encyclopædia Britannica. “Brown algae.” Encyclopædia Britannica, Encyclopædia Britannica, inc., 31 Jan. 2017.Available here

Image Courtesy:

1.’Red Algae on bleached coral’By Johnmartindavies – Own work,(CC BY-SA 3.0)viaCommons Wikimedia
2.’Kelp-forest-Monterey’By Stef Maruch – kelp-forest.jpg,(CC BY-SA 2.0)viaCommons Wikimedia