Algae - Definition, Characteristics, Types

Algae are organisms that are primarily aquatic and can carry on photosynthesis but are entirely different from other land or aquatic plants. Algae are very diverse and found in marine, freshwater ecosystems and moisture-rich areas.

Algae plays an essential role in providing the foundation for the aquatic food chains and producing a significant part of the oxygen needed to sustain life on Earth. Various studies have proved the ecological importance of algae.

You must be curious to know the contribution of algae to maintaining a balanced life cycle and improving marine ecosystems. In this article, we will provide details about algae characteristics , significance, types, negative impact, and various fields of applications

What Are Algae?

Algae is a term for a large and diverse group of aquatic organisms ranging from single-celled microorganisms to large multicellular forms. They are typically photosynthetic, meaning they use energy from sunlight to produce food and can be found in salt, fresh, and brackish water (a combination of salt and freshwater).

Algae have traditionally been used in many industries, such  as food, cosmetics, and pharmaceuticals. In recent years, they have also become an important renewable energy source due to their ability to produce biofuels.

Algae are also known to play an essential role in the health of aquatic ecosystems, as they are a critical part of both the base and top levels of the food chain.

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Algae Characteristics

• Algae can be unicellular or multicellular organisms.
• Macroalgae are large and multicellular aquatic plant-like organisms, while Microalgae are tiny and unicellular aquatic organisms.
• Algal cells are eukaryotic as they contain three types of double-membrane-bound organelles: the nucleus, the chloroplast, and the mitochondrion.
• The algae size ranges from 2 micrometres in diameter to large sizes up to 60 meters.
• It can be unicellular or multicellular and found in marine, freshwater, and moisture-rich environments.
• Algae have no well-defined body and lack structures like roots, stems, or leaves.
• It contains chlorophyll that helps in photosynthesis to produce nutrients while releasing oxygen and consuming carbon dioxide.
• Most algae are called photoautotrophs as they generate nutrients using light energy.
• The different algae species have different colours depending on the type and proportion of chlorophyll and other pigments contained by them.

• Reproduction in algae occurs in both asexual and sexual forms. Asexual reproduction occurs by spore formation or vegetative methods to produce identical offspring by cell division and colony fragmentation.
• Most algae live independently but can also form symbiotic relationships with various non-photosynthetic organisms like sponges, fungi, etc. They are called heterotropic.
• Algae can survive under various temperatures, humidity, or salinity. It grows in various habitats with extreme environmental conditions, from soil to water.
• Nutritional strategies of algae combine both photo autotrophy and heterotrophy. This ability is known as mixotrophy .

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Types Of Algae

Algae are found in a variety of different colours. The three types of algae based on their colour  are Red algae, Green algae, and Brown algae . The details of these algae’s kingdom, pigmentation, source, characteristics, and a few examples are discussed in the table below.

Significance Of Algae

Algae play a significant role in maintaining the ecological balance by acting as a primary food producer, habitat to marine species, and pollution indicator. Algae can be used to improve environmental parameters and build a balanced ecosystem. Some of the essential benefits of algae are as follows:

Source Of Oxygen

Algae contains chlorophyll that helps in the photosynthesis process to produce organic food by utilising energy from the sun and absorption of carbon dioxide.

One of the algae's significant functions is oxygen production as a by-product of photosynthesis.

The oxygen produced is utilised by marine species and creatures for their survival and helps to maintain ecological balance.

Source Of Food

Algae form the base of many food chains and are the source of food for numerous tiny creatures and organisms in the marine environment. The role of algae is vital as a food source for many aquatic species ranging from tiny worms, fishes, turtles, etc.

The growth of life in the ocean is dependent mainly on algae. Microalgae form the food source for small creatures which are again consumed by larger species, thereby maintaining the ecological cycle.

Provision Of Habitat

Large species of Macroalgae often provide habitats for other small species by facilitating their survival and growth in the aquatic environment. Different unique and rare species, including snails, skeleton shrimp, and sea urchins, can often be found within such a habitat.

Indicators Of Pollution In Water

The presence of algae in the water bodies is a good indication of water pollution level. Certain conditions in the aquatic environment facilitate the rapid growth of algae.

Scientists have studied what types of nutrients are favourable for algae growth. Accordingly, they can make inferences about the water's nature by analysing the algae's health.

Algae can reproduce rapidly, and scientists analyze the nature of algae to determine whether a similar type of algae is grown or whether there is a genetic change that can be caused by the pollution in the water.

Reduce Pollution And Indicate Climate Change

According to the latest research, algae are the major contributor to reducing pollution as they absorb significant carbon dioxide from the atmosphere. Algae can be used as an indicator of climate change that helps build up a balanced environment.

Algae require a large amount of carbon dioxide for their growth. Scientists compare the earlier growth of algae and recent algae growth and spread and get an idea about the increase in carbon dioxide in the atmosphere.

A substantial increase in algae growth rate indicates an increase in the amount of carbon dioxide in the atmosphere and vice versa.

Improve Soil Quality

Algae play an important part in introducing various organic matters into the soil, thus enriching the soil quality. When they die or dry up, they are used up by other soil microbes, forming a crust on the soil surface that can prevent soil erosion.

Some species of blue-green algae are significant to the environment as it fixes the nitrogen in the soil and improves Agriculture fertilizers . Soil algae replenish the loss of nitrates through leaching and drainage. They liberate large quantities of oxygen through photosynthesis in the soil environment and thus facilitate aeration in submerged soils.

Non-Conventional Fuel

Recent developments in science and technology have developed innovative ways to use algae as a fuel source. This is a significant step in dealing with the mass consumption of petroleum fuel and its adverse environmental impact.

The eco-friendly alternative is known as algal biofuel, which is a viable alternative to traditional fossil fuels. Algae can be used to produce ‘green’ fuel to address the problem of using conventional fossil fuels and their rapid depletion on Earth.

The Negative Impact Of Algae

The huge growth of certain microalgae in water bodies can produce toxins, disrupting the natural aquatic ecosystems and increasing the pollution level. In freshwaters, cyanobacteria are the primary source of toxins, and some eukaryotic algae also cause water pollution.

Research shows that algae generate toxins to protect themselves from being consumed by small creatures and animals.

The presence of nitrogen and phosphorus often results in the unrestricted growth of algae. Agricultural and industrial pollutants often affect the water bodies and facilitate the rapid growth of algae.

The excessive growth of algae can cause detrimental effects on aquatic systems, endangering the life of organisms and hampering human uses of the affected water sources.

Applications Of Algae

The extensive biological diversity of algae can be effectively utilised to produce a range of valuable bio-products naturally or via genetic processing. Algae production also has some advantages, such as low production costs, no land requirement, and the capacity to proliferate on a large scale in outdoor systems and under laboratory conditions. Numerous applications of algae are found in various fields, as mentioned below.

Food

Algae are enriched with carbohydrates, protein, vitamins, and minerals, so it is used in the food industry to produce dietary supplements. Algae can produce vegetable oil rich in omega-3 fatty acids, which is good for health.

Agriculture

Agriculture Organic fertilisers from algae are becoming a potential alternative to chemical fertilisers since they are rich in micronutrients, growth regulators, and other minerals that directly aid crop growth and yield.

Industrial

The various algae species supply natural pigments that can be utilised as alternatives to artificial chemical dyes and colouring agents.

Fuel

Algae can be a great source of biofuels as carbon-neutral fuels. Many microalgae species have significant lipid content, which can be turned into biodiesel.

Pharmaceutical

Algae with beneficial biochemical properties are utilised in manufacturing antibiotics and other medicines.

Bioplastic

Algae naturally create polymers that can be utilized in bioplastic manufacturing. Algae-based bio-plastic is biodegradable, making them a greener alternative to conventional plastics.

Pollution Prevention

Pollution Prevention Algae can also be used in wastewater treatment since they break down waste substances, decreasing the number of hazardous chemicals. Algae are also utilised in industrial plants to reduce carbon dioxide proportions in the air because it is used for photosynthesis by the algae.