Algae are a diversified group of aquatic entities that are capable of conducting photosynthesis. They are responsible for producing most of the Earth’s oxygen, which is majorly utilized by the marine entities. Some algae resemble plants(seaweed) but factually, they are neither plants nor animals. The seaweeds are made of many cells with fronds(structures similar to that of leaves of plants). Algae are one-celled entities and are spread across widely with over 20,000 known varieties of algae. They are usually found inhabiting the aquatic ecosystems, both the marine and freshwater ecosystems. Apart from oxygen requirements, algae are of great medicinal value and are also known to serve as food requirements for fishes.
Algae lack any of the plant structures such as stems, roots, and leaves as seen typically in plants. They are crucial is several food chains operating as primary producers of organic matter. Algae are also known to be utilized in wastewater treatment facilities thereby decreasing the risk from toxic chemicals and also finds its applications in some of the power plants to lessen the emission of carbon dioxide. Algae possess chlorophyll which assists them in manufacturing their own food through the process of photosynthesis and produce a huge amount of oxygen. As per some scientists, it is believed that algae generate about 87% of the oxygen of the world.
Characteristics Of Algae
Listed below are the general characteristics of algae that are also common to animals and plants such as algae exhibit specialized components and structures that are found only in animals(flagella and centrioles). Also, algae are capable of performing photosynthesis like plants.
- Habitat: Majorly algae are found inhabiting in the aquatic habitats. They are found thriving both in saltwater oceans and freshwater lakes. They can also survive in different levels of carbon dioxide and oxygen concentrations, varied range of temperatures, acidity, etc. For instance, the Dunaliellasalina is found inhabiting in hypersaline conditions such as the Dead Sea. The giant Kelp is found existing more than 200meters below polar ice sheets. The ones that are found in the illuminated regions of water are planktonic and the ones that cling to surfaces are referred to as benthic algae. They are also found inhabiting on land such as tree trunks, snow banks, soil, animal fur, etc.
- Algae are referred to as photoautotrophs as they are capable of producing their own nourishment through the process of photosynthesis with the use of light energy from the sun and carbon dioxide to produce oxygen and carbohydrates. A simple photosynthesis equation can be used to explain this,
Sunlight + Chlorophyll (in chloroplasts) + Carbon Dioxide + Water = Glucose + Oxygen
Algae are known as photoautotrophs as they reflect the use of sunlight to produce nutrients. However, there are some algal species that are heterotrophic which apply a variety of techniques to obtain food such as Osmotrophy(absorption of dissolved particles) and phagotrophy(engulfing food particles). There are a few other algae that are required to obtain essential vitamins or fatty acids and are referred to as auxotrophs.
- Algae can reproduce through sexual reproduction as well as asexual reproduction or vegetative methods wherein asexual reproduction involves the motile spore production. Simple division process takes place in vegetative methods to produce identical offspring followed by the colony fragmentation. Sexual reproduction, on the other hand, involves the fusion of gametes which is individually produced by each parent.
- Cellular nature: Algae can either be unicellular or multicellular entities
- Though algae exhibit the property of photosynthesis, they lack plant structures such as leaves, stems or roots. Algae lack a well-defined body structure but are often found resembling plant-structures.
Types Of Algae
Algae are widely spread and show tremendous variety. Listed below are a few types of algae:
- Blue-green algae – Also known as cyanobacteria, they are most commonly found in rivers, dams, reservoirs lakes, etc. They acquire their energy through photosynthesis and are more crucial in the nitrogen-fixation process.
- Red algae – Also known as Rhodophyta, they are found in freshwater ecosystems and are a distinctive type of species. The color of this pigment is attributed to phycoerythrin and phycocyanin pigments. They also possess chlorophyll A.
- Green algae – They possess a primary pigment – Chlorophyll A and B along with xanthophylls and beta carotene. Example: Hydra.
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