Bubble algae (Ventricaria ventricosa), also known as sailor’s eyeballs or sea grapes, are huge green balls recognized for their distinctive appearance that is quite intriguing at first sight. They belong to the genus Valonia, order Cladophorales, and family Valoniaceae.
The bubble-like structures are spherical and consist of cells packed closely together. They are the largest known single-celled organisms, with some individual specimens reaching the size of a tennis ball.
While bubble algae may appear harmless, they can become problematic. They can rapidly overrun an aquarium, crowding out other marine life and disrupting the delicate balance of the ecosystem. Additionally, they can harm fish and other creatures because their thick, bubble-like structures can trap and suffocate them.
Continue reading to learn more about bubble algae growth, which can be both aesthetically pleasing and a nuisance to aquarium hobbyists.
Appearance
Size: On average 1 – 4 cm (0.4 – 1.6 in)
Color: Ranges from green, brown, or silver
Bubble algae are microalgae but they appear as macroalgae due to their size and the ability to see them with the naked eye. Their surface is typically smooth, and the color can range from grass green to a dull, brownish-green. However, it can appear blackish or silvery when submerged in water. This variation is determined by the quality of the plant’s chloroplasts.
When viewed up close, these plants exhibit a unique, textured appearance. The individual cells that constitute the algae are hexagonal and are packed closely together, forming a lattice-like pattern. This pattern imparts a distinctive, honeycomb-like appearance to the algae.
Habitat
Bubble algae are a hardy species that can inhabit all oceans worldwide but are primarily found in tropical and subtropical regions, including the Caribbean, the Gulf of Mexico, the Indian Ocean, and the Pacific Ocean.
They are typically grown in intertidal zones and shallow reef environments, dead spots, and attached to new live rocks, corals, and other hard surfaces. These algae rapidly grow in an unseen location in a stand.
Bubble algae can tolerate a wide range of water conditions. However, they tend to thrive in warmer waters with moderate to high levels of nutrients. They can also handle a broad range of salinity levels, making them well-suited to various coastal environments.
They can also be found in aquariums and reef tanks. In these settings, many consider them a pest species due to their rapid growth and ability to overrun an environment quickly. However, even in those cases, they provide food and habitat for various marine organisms.
Preventing the Rapid Growth of Bubble Algae
In just a couple of weeks, bubble algae outbreaks can cover a significant portion of any environment, including rocky substrates or coral skeletons, disrupting the balance of the ecosystem. They also clog pumps and other equipment, leading to maintenance issues. Here are some quick tips on what you can do to prevent this:
Introduce a competing species
The presence of coralline algae in a reef tank can be a sign of good luck, as these algae compete with bubble algae for nutrients and space, potentially limiting their growth. Hobbyists need to maintain proper water parameters for the removal of these algae.
Some species of fish, like rabbitfish, are known to eat bubble algae. Therefore, introducing these natural predators into a display tank is a reasonable method of control.
Maintain optimal water nutrient levels
The high levels of phosphate and nitrates in the water can contribute to the rapid growth of bubble algae. Therefore, maintaining proper water chemistry, including monitoring the level of excess nutrients, is crucial in preventing an algae outbreak in the water column. The nitrate levels can be kept low with good filtration and nutrient removal systems.
Some hobbyists use hydrogen peroxide to kill the algae on rock surfaces, which is an easy removal procedure that won’t completely kill live rock.
Diet
Their primary source of nutrition is sunlight. Like any plant, they contain chlorophyll, a pigment that allows them to convert light energy into organic matter through photosynthesis.
They can also absorb nutrients from the surrounding water and utilize dissolved nitrogen, phosphorus compounds, and other trace elements.
Reproduction
They reproduce asexually through fragmentation, but some species may also produce spores. These spores can attach themselves to live rock or other hard surfaces in the tank and begin to grow.
Their reproductive strategy is asexual through cell division. A portion of the algae breaks off and develops into a new bubble. As such, this type of reproduction allows bubble algae to colonize new areas quickly.
Fragmentation typically occurs when the algae are disturbed by physical contact or environmental factors such as storms or strong currents. Once a piece of the algae breaks off, it can grow and form dense mats or clumps.
In the wild, they reproduce seasonally, with peak reproductive activity occurring in the warmer months. In aquariums and reef tanks, where conditions are more stable and nutrient-rich, bubble algae can reproduce more frequently.
Due to their ability to reproduce and colonize rapidly, it is necessary to adopt a proactive approach to prevent bubble algae from taking over an aquarium. This strategy can include regular water changes, maintaining proper water chemistry, and avoiding overfeeding. It is also best to remove any bubble algae that appear as soon as possible.
Threats
Like all living organisms, bubble algae can be affected by a large number of threats. Some of them are:
- Pollution: Water pollution can alter the pH of the water, introduce toxins and heavy metals, and reduce the nutrients. It can also cause eutrophication, which is the excessive growth of algae due to an overabundance of nutrients in the water.
- Overfishing: Overfishing can disrupt the ecosystem’s natural balance by reducing the number of herbivorous fish that feed on algae. This action can lead to an increase in the growth of bubble algae, which can outcompete other algae species and harm coral reefs.
- Climate change: Climate change can cause changes in water temperature, ocean acidity, and sea level.
- Physical damage: Physical damage can occur due to human activities such as boating, diving, or fishing. Natural events like storms or hurricanes can prevent it from growing and reproducing.
7 Fun Facts About Bubble Algae
- The bubbles of the algae can trap air, allowing them to float to the surface of the water. This helps them access more sunlight for photosynthesis.
- While they are generally green, the color of bubble algae can vary depending on the quality of light they receive. In certain conditions, they may appear blackish or silvery.
- In the wild, they prevent soil erosion by stabilizing sediment on the ocean floor.
- They are one of the largest single-celled organisms in the world. Each ‘bubble’ is a single cell that can reach up to 5 cm in diameter.
- Despite their simple structure, bubble algae are incredibly resilient. Their thick cell walls protect them from physical damage and predators.
- In addition to photosynthesis, dissolved organic matter can be absorbed from the water, providing them with an additional source of nutrients.
- Some species of fish, like the Emerald Crab, are known to eat bubble algae, making them a natural solution for controlling their growth in aquariums.
FAQs
What is bubble algae made of?
They are large, spherical cells reaching several centimeters in diameter. These cells are filled with a gel-like substance called the cytoplasm, which contains various organelles such as the nucleus, chloroplasts, and mitochondria.
The cell walls of bubble algae are composed of cellulose, a complex carbohydrate that provides structural support and protection to the cells. The cell walls also contain a layer of mucilage, a sticky substance that helps the algae attach to hard surfaces.
Who eats bubble algae?
Bubble algae are not a preferred food source for most marine organisms, as their thick, gelatinous cell walls and high salt content make them difficult to digest. However, some herbivorous species, like sea urchins, feed on bubble algae. Some species, such as the collector urchin and the pencil urchin, have specialized mouthparts that can crush and break apart rigid cell walls.
