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Cladophora is a genus of Ulvophyceae with reticulated filaments (green algae). Reticulated filaments are present in Cladophora. Because of the enormous range in their looks, which is affected by habitat, age, and environmental conditions, the genus Cladophora has several species that are difficult to distinguish and categorize. Cladophora filaments branch and do not undergo conjugation, unlike Spirogyra filaments. Ulvophyceae, also known as ulvophytes, are a group of green algae classified primarily by ultrastructural morphology, life cycle, and molecular phylogenetic data. Ulva, the sea lettuce, belongs here. Caulerpa, Codium, Acetabularia, Cladophora, Trentepohlia, and Monostroma are among the other well-known members.

General Properties of Cladophora

The Ulvophytes have a wide range of morphology and environment. The majority are seaweeds, such as the ones mentioned above. Others, such as Rhizoclonium, Pithophora, and several Cladophora species, survive in freshwater and are considered weeds in some locations. Ulvophyceae origins and early diversification are thought to have occurred in the late Neoproterozoic era. Although most modern lycophytes are marine macroalgae (seaweeds), ancient chlorophytes could have been unicellular freshwater green algae. Macroscopic growth was acquired independently in the various major Ulvophyceae lineages, according to molecular phylogenetic evidence (Ulvales-Ulotrichales, Trentepohliales, Cladophorales, Bryopsidales, and Dasycladales). Although fossils are few, some good candidates can be found in a mid-Ordovician lagerstatten.

Following the hierarchical classification from order to family to genus, we reach the genus of algae Cladophora. As mentioned earlier, the genus of Cladophora has many different species that can be really difficult to identify. A haploid gametophyte and a diploid sporophyte of Cladophora are two multicellular phases in its life cycle that look similar. The only method to distinguish between the two stages is to count their chromosomes or look at their progeny. Mitosis creates haploid gametes in the haploid gametophyte, and meiosis produces haploid spores in the diploid sporophyte. The sole observable distinction between Cladophora gametes and spores is that gametes have two flagella while spores have four. The algae Cladophora species can be a big nuisance, causing significant changes in benthic conditions, i.e. at the lowest levels of a water body, especially when phosphorus levels are high. The following is a picture of Cladophora:

Cladophora balls are made up of photosynthetic filaments from the algae. In Devon, England, a large number of these balls were thrown ashore. They were 2.5 cm in diameter on average, and there were several million of them forming a layer. This is not to be confused with marimo, which is now known as Aegagropila linnaei and is still classified as Cladophora. Cladophora is a widespread genus, and infestations are rarely considered invasive. They may be viewed as beneficial, a nuisance, or an outright pest depending on where they appear.

According to Cladophora's information about their developmental characteristics, their growth is largely harmless. In the developmental stage, it serves as a source of food for many fish and other aquatic species. It is also used as a buffer for the sequestration of nutrients in the water body and protection from solar ultraviolet radiation for some aquatic organisms.

The algae Cladophora becomes a problem when unique circumstances result in dramatic overgrowth such that algal blooms arise and floating mats are formed and spread on the bed of the water body. Hypertrophication or excessive mortality of rival species produce high amounts of dissolved phosphorus, for example. Extensive floating mats obstruct circulation, which is important for the aeration of deeper water, and they kill photosynthesizing organisms developing beneath them by blocking the path of the light. These mats also cause trouble by providing hindrance to the fishing industry by blocking nets and making it impossible to use lines. The piles of decomposing trash that wash ashore around water bodies like the Great Lakes in the North American continents lower waterfront property prices. Although their ecological linkages are not yet evident and may be complex, Quagga mussel numbers have increased within the same time window as Cladophora blooming.

Species-Specific Examples of Cladophora

Cladophora glomerata is a macroscopic green alga and is found in the Cladophora habitat limited to fast-flowing reaches downstream of weirs or in fish passes. It is found worldwide in most freshwater sources. Cladophora glomerata is one of several species that are considered a nuisance in recreational bodies of water. Overgrowth of these algae has been linked to the spread of invasive zebra mussels in North America's Great Lakes.

Cladophora rupestris is also algae-like Cladophora glomerata and is a densely tufted plant with dark green or bluish-colored dull fronds that grow up to 20 cm in height. Typical specimens branch out in an uneven, whorled, or opposing pattern from the base. The seaweed has a coarse texture due to its stoutness, density, and branch arrangement.

Cladophora socialis is also a green algae species. Cladophora socialis can be found in a variety of environments around the world, including the Atlantic and Pacific Oceans. Cladophora vagabunda belongs to the Cladophoraceae family of marine green algae. It is sold all around the world.

Marimo - The Cladophora Ball

Marimo (also known as Cladophora ball, moss ball, or lake ball) is an uncommon growth form of Aegagropila linnaei (a filamentous green algae species) in which the algae form huge green velvety balls.

In Japan and Northern Europe, these species are present in a number of lakes and rivers. These marimo balls form colonies in Japan and Iceland but nowadays their population is declining.

Marimo was first described in the 1820s by Anton E. Sauter, found in Lake Zell, Austria. The genus Aegagropila was established by Friedrich T. Kützing (1843) with A. linnaei as the type species based on its formation of spherical aggregations, but all the Aegagropila species were transferred to subgenus Aegagropila of the genus Cladophora later by the same author (Kützing 1849). Subsequently, A. linnaei was placed in the genus Cladophora in the Cladophorales and was renamed Cladophora aegagropila (L.) Rabenhorst and Cl. sauteri (Nees ex Kütz.) Kütz. Extensive DNA research in 2002 returned the name to Aegagropila linnaei. It is distinguished from the Cladophora genus by the presence of chitin in the cell walls.

Takiya Kawakami, a Japanese botanist, named the algae marimo in 1898. Mari bounces around like a bouncing ball. Plants that thrive in water are referred to as mo. Torasampe (lake goblin) and tokarip are Ainu native names (lake roller). Although they are unrelated to moss, they are sometimes sold in aquariums as "Japanese moss balls." Local fisherman at Lake Mvatn in Iceland calls the lake balls klaustur (kla = ball, sktur = muck), where the "muck" is any weeds that get trapped in their fishing nets. The genus name Aegagropila means "goat hair" in Greek.

The alga has three growth forms:

  • It can grow on rocks, usually found on the shaded side of the rocks.

  • It can exist as free-floating filaments. Small tufts of unattached filaments frequently form a carpet on the muddy lake bottom.

  • It can form a lake ball where the algae grow into sizable balls of densely packed algal filaments that radiate from the center. No kernel is present in the balls.

The adaptation of marimo colonies to low light circumstances, as well as the dynamic interaction of wind-induced currents, light regime, lake topography, bottom substrate, and sedimentation, all contribute to their survival.

Marimo grows at a pace of roughly 5 mm per year. They can grow up to 20 cm–30 cm in length in Japan's Lake Akan. At depths ranging from 2m–2.5m, thick colonies of marimo grew to about 12 cm in diameter and created well-defined patches on the lake floor in Iceland's Lake Myvatn. The marimo's spherical shape is maintained by modest wave motion that twists it every now and then. Shallow lakes with sandy bottoms provide the greatest conditions for this.

The balls are green all the way around, ensuring that they can photosynthesize regardless of which side is facing up. The ball is also green on the inside, with dormant chloroplasts that will become active in a matter of hours if it breaks apart. The wave action also removes any dead organic material from the balls. Wave movement is required to tumble the marimo balls so that each one reaches the light in certain colonies, which have two or even three layers. In comparison to a leaf, the spherical shape has a low surface-area-to-volume ratio, which limits photosynthesis and thus the marimo balls' maximum growth.

Marimo prefers lakes with low to moderate biological activity and moderate to high calcium levels as their preferred habitat. The species is primarily found in parts of Europe that were once covered in glaciers, especially in Northern Europe, as well as in a few locations in Japan. It has been discovered in North America and Australia, but it is quite rare. The amount of nutrients in the water affects the species. The disappearance of many lakes is assumed to be owing to an oversupply of nutrients (due to agriculture and fish husbandry), as well as mud deposition from human activity.

Although the species is still widespread in Austria's Lake Zeller (where it was initially discovered in the 1820s), the lake ball growth form hasn't been seen there since roughly 1910. A similar thing has happened in most of England and Scotland, where the connected form is primarily encountered. In 1978, large colonies of marimo were discovered in Iceland's Lake Myvatn, although they have since declined dramatically. Due to an oversupply of nutrients in the lake, the marimo has nearly completely vanished by 2014.

Although the species can still be found in Japan, populations have dropped there as well. The conservation of the lake balls is a major priority at Lake Akan. Since the 1920s, the marimo has been protected in Japan and since 2006 in Iceland. Lake Akan and Lake Mvatn are both protected as national parks and nature reserves.

Marimo balls are a unique find. Every October, the Ainu people of Japan hold a three-day marimo festival near Lake Akan. The lake balls also serve as a medium for environmental education due to their appealing look. Hand-rolled souvenir balls are made from free-floating filaments. Marimokkori, a popular plush toy creature, incorporates the human form of marimo algae into its design. Marimo is sometimes offered for aquarium display, and it usually comes from Ukrainian lakes like the Shatsky Lakes. Balls sold in Japanese aquarium stores are made in Europe, and obtaining them from Lake Akan is illegal.

Zebra mussels were identified in moss balls sold in pet stores across North America on March 2, 2021, according to the United States Geological Survey. Invasive zebra mussels had been discovered in moss balls in 21 states by March 8. The first discovery at a Seattle Petco sparked these investigations. To prevent the moss balls from spreading to local waterways, owners of fish tanks were advised to sanitize them by boiling, freezing, or bleaching them before discarding them. Moss balls were voluntarily recalled in Petco and PetSmart stores. If the mussels make it to open water in Washington, they might cost the state USD100 million each year in power and water system upkeep.

In the end, Cladophora, a genus of green algae having reticulated filaments, is an aquatic or hydrophilic organism sharing observable similarities with both algae and plants. Just like most of the algae, Cladophora too is a nuisance and a problem, especially in water bodies that do not have any way of recycling their water content, all the while accumulating chemicals such as phosphorus over time, giving sufficient nutrition to the algae Cladophora. With the growth of the different species over time, water bodies such as the Great Lakes mentioned above in the North American continent, causing the death of much of flora and fauna. This happens as an increased population of Cladophora, especially in the bottom zones, takes up most of the nutrients for their growth along with rapid utilization of photosynthesis for their growth processes. Several species, such as Cladophora glomerata, Cladophora rupestris, Cladophora socialis, Cladophora vagabunda, etc., are the ones commonly found in all the still and freshwater lakes of the world. It can even grow in the farmlands and can be a nuisance for the farmers. Therefore, in order to avoid the growth of cladophora, either recycling of the water in the water body or cleanliness is to be maintained at freshwater sources of human consumption. Also, in order to avoid the outgrowth of the algae, water pollution should be checked for toxic elements like phosphorus getting mixed into the water source. Thus, keeping these measures in mind, a significant amount of problems coming out of the growth of Cladophora can be controlled.


Cladophora is a species of green algae. Branches are present in cladophora but no conjugation is present. Haploid gametophyte and diploid sporophyte are the two stages of reproduction that are present in Cladophora. From the filaments of algae, Cladophora balls are present. They are responsible for providing food to many species of fish and other organisms.

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FAQs on Cladophora

1. Is Cladophora a bacteria?

The macrophytic green alga Cladophora glomerata is common in the Great Lakes, with substantial accumulations along shorelines throughout the summer months. Cladophora has recently been discovered to have large levels of the faecal indicator bacteria E. coli and enterococci.

2. Is Cladophora invasive?

Cladophora is a type of green algae that can be found in abundance around the Great Lakes' shorelines. These invasive species activities boost phosphate availability for Cladophora while also improving water clarity.

3. Is Cladophora homogametic?

The gametes are known as homogametic or isogametes when the male and female gametes cannot be distinguished morphologically. Cladophora, for example. Heterogametes are gametes that can be distinguished morphologically from male and female gametes.

4. Is Cladophora harmful?

Cladophora does not pose a health threat to humans. Cladophora decomposing on a beach, on the other hand, fosters bacterial growth, which can be harmful to human health. Furthermore, crabs that wash ashore with the algae can attract big flocks of gulls, resulting in high levels of feces and germs.

5. How do Cladophora reproduce?

Sexual reproduction in Cladophora is isogamous. Almost every species on the planet is heterothallic. Isogametes are made in the same way that zoospores are made. Four quadri-flagellate zoospores are generated as a result, and they exit through an apical pore.