Algae are an important group of aquatic organisms that are capable of photosynthesis. Many people are familiar with some types of algae, such as seaweeds (phytoplankton or kelp), lake algal blooms, or pond scum. However, there is an incredibly diverse and varied universe of algae that is not only beneficial to us, but essential to our lives.

Table of Contents:

Examples of Green Algae

Green Algae Bloom

Algae are a diverse group of organisms that are able to produce oxygen via photosynthesis, although they are not closely related to us. They are distinct from ground plants due to their lack of leaves, roots, stems, and a vascular system. Most algae are unicellular and exist in a range of shapes and sizes, from microscopic cells to giant kelp fronds that can be up to 60 meters wide. Algae can be found in both freshwater and saltwater habitats.

Although “algae” does not constitute a natural unit that has descended from a common ancestor, cyanobacteria (also known as blue-green algae) and eukaryotic organisms (all other algal species) are still generally grouped together under this term. According to Linda Graham, a botany professor, this is popular in the informal “algae” community. It is also interesting to note that species of cyanobacteria are related to chloroplasts, which in land plants is the source for photosynthesis. According to the University of California Museum of Paleontology, these early cyanobacteria were swallowed up by primitive plant cells sometimes in the early Cambrian period or late Proterozoic period.

Prokaryotes such as Archaea and Bacteria lack an ordered cell structure, making them simpler species with their DNA floating freely in the cytoplasm. On the other hand, Eukaryotes such as protists, insects, and fungi have a more cohesive body structure, with mechanisms called organs to conduct cellular roles and their DNA centrally located in a nucleus.

Algae are incredibly adaptable organisms that can be found in a variety of aquatic localities, including saltwater seas and freshwater lakes. They are capable of surviving in a range of temperatures, oxygen and carbon dioxide concentrations, turbidity and acidity levels. Furthermore, they can live independently or form symbiotic relationships with non-photosynthetic organisms, such as ciliates, sponges, molluscs and fungi.

Examples of Green Algae

1. Chlamydomonas
2. Spirogyra
3. Ulva
4. Cladophora
5. Volvox

Marimo

Marimo is an uncommon form of Aegagropila linnaei which has a soft, velvety texture and grows into large, green spheres. This species is native to Japan and Northern Europe and can be found in various lakes and rivers. Unfortunately, marimo colonies in Japan and Iceland are close to being wiped out.

Order: Cladophorales

Class: Ulvophyceae

Phylum: Chlorophyta

Scientific name: Aegagropila linnaei

Family: Pithophoraceae

Sea Lettuce

Sea Lettuce (Ulva lactuca), an edible green alga in the Ulvaceae family, is the type species of the Ulva genus.

Scientific name: Ulva lactuca

Phylum: Chlorophyta

Class: Ulvophyceae

Order: Ulvales

Family: Ulvaceae

Rank: Species

Ulva Intestinalis

In the Ulvaceae family, Ulva intestinalis is a green alga commonly known as Gutweed, Sea Lettuce, and Grass Kelp. The tubular members of the Sea Lettuce genus Ulva were initially classified under the genus Enteromorpha, until they were reclassified by genetic work completed in the early 2000s.

Scientific name: Ulva intestinalis

Rank: Species

Higher Classification: Ulva lactuca

Phylum: Chlorophyta

Family: Ulvaceae

Order: Ulvales

Haematococcus pluvialis

Haematococcus pluvialis is a species of freshwater Chlorophyta from the Haematococcaceae family. It is well known for its high content of the important antioxidant astaxanthin, which is used in aquaculture and cosmetics.

Scientific name: Haematococcus pluvialis

Phylum: Chlorophyta

Higher Classification: Haematococcus

Order: Chlamydomonadales

Rank: Species

Family: Haematococcaceae

Dead Man’s Fingers

Codium fragile, commonly known as Dead Man Fingers, Green Sea Fingers, Forked Felt-Alga, Felty Fingers, Stag Seaweed, Green Sponge, Sponge Seaweed, Green Fleece, and Oyster Thief, is a genus of seaweed in the Codiaceae family.

Phylum: Chlorophyta

Scientific name: Codium fragile

Rank: Species

Higher Classification: Codium

Class: Ulvophyceae

Order: Bryopsidales

Chlorella

Chlorella is a single-celled green algae belonging to the genus Chlorophyta. It is typically triangular in shape, with a diameter of approximately 2 to 10 μm, and lacks flagella. Its chloroplast contains both chlorophyll-a and -b, which are green photosynthetic pigments.

Scientific name: Chlorella

Rank: Genus

Class: Trebouxiophyceae

Phylum: Chlorophyta

Order: Chlorellales

Higher Classification: Chlorellaceae

Water Silk

Spirogyra is a type of Zygnematales filamentous chlorophyte green algae, known for its chloroplastic helical or spiral structure. It is commonly found in freshwater habitats, with over 400 species of Spirogyra discovered worldwide.

Kingdom: Plantae

Class: Zygnematophyceae

Scientific name: Spirogyra

Division: Charophyta

Order: Zygnematales

Rank: Genus

Green Algae Bloom

An algal bloom is an abrupt increase in the population of aquatic photosynthetic entities, including both multicellular, macroscopic organisms such as marine algae and unicellular, microscopic algae. It is usually identified by a discoloration of the water due to the pigments of the algae. While the term generally refers to unicellular, microscopic algae, it can also include macroscopic algae, such as those found in a kelp forest.

The term ‘algal bloom’ has varying definitions depending on the scientific field, ranging from a small, harmless bloom to a large, harmful event. As algae encompass a wide variety of organisms with different growth rates, sizes, and nutrient requirements, there is no definitive level that defines a bloom. Therefore, blooms can be quantified and distinguished based on several factors, such as new algal biomass measurements, photosynthetic pigment concentration, negative effect bloom-quantification, or relative algae concentration in relation to the rest of the microbial community.

Algal blooms are caused by the eutrophication process, which is the result of a nutrient, such as nitrogen or phosphorus, from fertilizer runoff entering the water environment and causing excessive algae growth. These blooms can have both beneficial and harmful effects; they can feed higher tropical levels or block sunlight from reaching other organisms, cause oxygen depletion in the water, and secrete toxins into the water depending on the organism. When these blooms cause damage to animals or the environment, they are referred to as “Harmful Algal Blooms” (HAB) and can lead to the death of fish.

HABs (Harmful Algal Blooms) have been observed to have detrimental effects on a wide array of aquatic organisms, particularly marine mammals, seabirds, sea turtles, and finfish. The consequences of HAB toxins on these populations can include damaging alterations to their developmental, neurological, immunological, or reproductive capacities. The most visible impacts of HABs on marine wildlife are large-scale mortality events linked to toxin-producing blooms.

Algal blooms are a major health hazard for humans due to their production of toxins that make water unsuitable for consumption, as well as their ability to quickly spread and contaminate large bodies of water. Furthermore, when this polluted water comes into contact with human skin, it can cause severe irritation, itching, and even skin diseases.

The emergence of significant algal blooms will contribute to major deaths of marine life. This will lead to a dead zone in the area around the algal blooms, consisting of dead animals and plant life. The foul smell of this dead zone will cause the remaining aquatic life to be driven away from the area. Additionally, as the growth of algal blooms results in the death of aquatic life, it can cause large-scale losses to fishermen who rely on fishing as a means of income.

Many businesses, such as food processing firms, need only purified water from resources of water to power their development. This ensures that if algal blooms occur, additional water treatment costs will arise, resulting in increased overhead costs.

Farmers must use fertilizers to supply their crops with insufficient nutrients and increase yields. To do this optimally, they should use methods such as top dressing or rubbing, depending on the nutrients needed. It is important for farmers to consult agricultural experts on the type and amount of fertilizer to use.

Disinfection and tertiary processing, including nitrification and sludge disposal, is essential to prevent the introduction of unnecessary nutrients from large sources of water, such as rivers, ponds, oceans, and streams.

The drug has been found to be effective in combatting algal blooms in smaller water sources such as large wetlands or small lakes, providing a simple control over the substance’s effect as well as the aquatic life.

Ultrasound treatment equipment utilizes ultrasonic sound waves in water bodies to detect algal blooms and if found, monitor their growth, decreasing the growth of algae by up to 90%.

Individuals must take the initiative to reduce pollution and save the environment. This can be done by minimizing waste, recycling, and reusing items. When individuals practice these habits at home, school, and work, it can help reduce the amount of nutrients in water sources and make water treatment easier.

Questions and Answers:

Q1) Give two examples of green algae?

A1) Two examples of green algae are Chlorella and Spirogyra.

Ans: Chlorella and Ulva intestinalis

Q2) What are the consequences of an Algae Bloom?

Ans: **Eutrophication**

Stay informed about NEET and other related topics on Green algae with the latest news.

Further Reading:

Blue-Green Algae

Economic Importance of Algae

Chara: Classification, Structure, and Life Cycle

Oedogonium: Classification, Structure, and Life Cycle