Algae: Characteristics, Types and Examples

Introduction

Alga is a name that characterises a huge and varied group of eukaryotic photosynthetic organisms. They do not have the same ancestor, and might not be related to one another. Good examples of multicellular algae are the massive kelp and brown algae. Euglenophyta, dinoflagellates and diatoms are good examples of unicellular algae.

The majority of algae requires a humid or watery environment. Hence, they are prevalent in water bodies or near them. They are like another category of photosynthetic creatures anatomically similar to those that grow on land. Nevertheless, this is where the differences end, as algae do not have the structural components typical of plants, like the true stem, stems, and leaves.

In addition, they do not have vascular tissue that circulates vital liquids and nutrients throughout their bodies. Algae may be unicellular, such as Chlamydomonas, or multicellular, such as Spirogyra.

The algae are structurally composed of distinct cell walls, cell membranes, nucleus, the cytoplasm, and the chloroplast. The chloroplast has a cup shape in Chlamydomonas while it is ribbon, like in Spirogyra.

Pyrenoids, which are starch-rich bodies, form essential to the chloroplasts found in green algae. Algae are able to make their own food through photosynthesis since they have chlorophyll. Certain algae contain other pigments, such as a blue pigment called phycocyanin, the brown pigment called fucoxanthin, or the red pigment called phycoerythrin. According to the color present, the algae are known as brown, blue, green, or red algae.

Algae are found in seas, lakes, rivers, ponds, brackish water, and even snow. They are generally green; however, they are found in a range of hues. For instance, the algae that live in the snow have carotenoid pigments as well as chlorophyll. This gives the surrounding snow a distinctive red color.

Characteristics of Algae:

1. Algae can be single-cell organisms or multicellular species.
2. Because algae lack a well-defined body, they lack structures such as roots, stems and leaves.
3. Algae are usually photosynthetic organisms, which are able to synthesise their food.
4. Algae thrive where there is enough moisture.
5. Asexual and sexual reproduction is also possible in algae. Spores are generated, which are used in asexual reproduction.
6. Algae are free-living organisms that can create symbiotic relationships with other organisms.

Algae come in a variety of shapes and sizes. However, the following are some of the most well-known types:

1. Rhodophyta- They are commonly known as red algae, a species found in both marine and freshwater habitats. The pigments phycocyanin and phycoerythrin are responsible for the algae’s distinctive red hue. Chlorophyll-a, and other pigments that give a green hue are also present. They do not, however, contain chlorophyll b or beta-carotene.
2. Green algae: It is a broad category of algae that includes the principal photosynthetic pigments chlorophylls a and b, as well as auxiliary pigments such as xanthophylls and beta carotene. Green algae perform photosynthesis on behalf of higher organisms. Green algae species have symbiotic relationships with other organisms. Multicellular, unicellular, colonial, flagellates and others are among them. Green algae such as Spirogyra, Ulothrix and Volvox are good examples of this.
3. Blue-green algae: Blue green algae was once one of the most well-known algae types. However, because blue-green algae are prokaryotes, they are not currently recognised to be part of the algal family, as the bulk of algae are eukaryotes. These algae, sometimes known as cyanobacteria, exist in aquatic or wet settings, similar to other algae.
4. From an ecological standpoint, some types of blue-green algae are beneficial to the ecosystem because they aid in nitrogen fixation in the soil. They are known as nitrogen-fixing bacteria because of this. For example, Nostoc, Anabaena, and others. On the other hand, other types of blue-green algae may be toxic to humans. They could be neurotoxic, causing disorders affecting the nerve or respiratory systems such as paralysis or hepatotoxicity, causing liver failure. They can also function as environmental health indicators by identifying the intensity of pollution.

Algae Examples: Ulothrix, Fucus, Porphyra, Haematococcus pluvialis, Ascophyllum nodosum, and Spirogyra are the most well-known algae.

Algae’s uses: Algal biofuel is a type of biofuel made from algae. Thanks to recent technological and scientific advances, algae can now be used as a fuel. The usage of green alternatives, such as algal biofuel, has been pushed as demand for petroleum-based products has grown and the environment’s health has deteriorated.