Mallomonas

Mallomonas is the scientific classification for a genus of golden algae known for having a distinctive covering of bristles and scales. They have two flagella, or thin whip-like structures, that are unequal in length and help them move in water. Mallomonas are generally found in bodies of freshwater, where they can sometimes present a problem for wildlife. The presence of Mallomonas in growing numbers is significant because it can kill fish, and it is an indicator of pollution.

Background

The name Mallomonas comes from the Greek words mallos, meaning "lock of wool," and monas, meaning "single unit" or "single organism." German entomologist and naturalist Maximillian Perty named the genus. Perty was an enthusiastic investigator of microscopic aspects of natural science. He was the first to identify the flagella and the bristles on the Mallomonas. He publicized his findings in 1852. However, he was unable to see the scales that are also part of the cell covering of the Mallomonas. These were first observed and described in 1893. The genus is also known as Mallomonas Perty.

Mallomonas is a type of algae commonly known as golden algae. It is formally known as a chrysophyte. The nickname is derived from the golden-brown color of water where large colonies of the algae are found. Chryso is a Greek word meaning "golden," while phyta is from the Greek word for "plant." Mallomonas is the largest subgroup of algae under the class synurophyceae under the larger Chrysophyte grouping.

Algae are part of the lowest level of the aquatic food chain. Microscopic animals, or zooplankton, eat these microscopic plants, or phytoplankton. Small fish and insects eat the zooplankton, which are then eaten by larger forms of animal life.

Overview

Mallomonas are single-celled forms of algae. They are mostly oval in shape and covered with scales made of silica, an inorganic material that is also found in rocks. The arrangement of these cells—including their shape and the ways in which they overlap—helps to distinguish various species of Mallomonas from one another. In most forms of Mallomonas, small spines or bristles protrude from some of the scales, creating a hairy appearance. The bristles can become detached, especially when preserved.

They have two flagella that help with motility, or the ability to move, in water. One is fully developed and visible under a lighted microscope. The other flagellum is smaller and generally only visible with an electron microscope. The second flagellum has a swollen area that is thought to be related to phototaxis, or the process by which living organisms are either attracted toward or repelled from a light source.

The main body of the alga has two chloroplasts, the compartments in which photosynthesis takes place. Photosynthesis is the process by which plant life converts sunlight and carbon dioxide into a food source. In Mallomonas, these chloroplasts are a gold or golden brown color. In addition to being able to create food through photosynthesis, chrysophytes are heterotrophic and able to absorb nutrients from their environment.

Mallomonas prefer a freshwater environment with a pH that ranges from slightly acidic to neutral. They usually reproduce by cellular division. Sexual reproduction, while rare, is possible. More commonly, a cell divides to form daughter cells, which can then rest in sediment at the bottom of a body of water until a later time. The cysts in which these cells are encased can survive even in inhospitable conditions.

Although Mallomonas are common and can exist in vast numbers, it is often difficult to determine how many there are in a given area. That is because the cells are fragile and tend to deteriorate quickly when removed from their native habitat. Still, those found in fossils can help researchers determine what the condition of the body of water in which they were found was like centuries ago. Researchers have found fossilized remains of life forms like the contemporary Mallomonas that date back between fifty-six and forty million years ago.

Mallomonas, like all algae, are an important part of the food chain that supports all life on Earth. However, golden algae can sometimes suddenly develop into what is known as a toxic bloom. A bloom is an overgrowth of algae that creates dangerous conditions for one or more forms of life residing nearby.

In the case of golden algae, including Mallomonas, scientists have not found a specific trigger for these toxic blooms. Some possibilities include changes in temperature, changes in water speed, or changes in the water's chemical makeup. It has been noted that the blooms are more likely to occur in cooler weather.

When something occurs that allows the golden algae to multiply into large quantities, they overwhelm the other phytoplankton living in the area. The golden algae, including Mallomonas, then become stressed and give off a special chemical substance. The substance is thought to be the algae's way of generating more food by killing other organisms that the golden algae can then use as a food source. The chemical, when combined with minerals already in the water, creates a toxin that affects the gills and internal organs of fish, which can kill them through asphyxiation.

A large bloom of Mallomonas or other golden algae does not automatically result in a fish kill. Unlike other types of algae bloom, a golden bloom is not toxic to other life forms. Researchers can monitor bodies of water for potentially dangerous blooms by examining water samples to determine the number of Mallomonas or other forms of golden algae present. They also look for how many chrysophytes are present in relation to other forms of algae. Because of the type of acidic water conditions Mallomonas prefer, their presence in water can also be an indicator of certain types of pollution.

Bibliography

"Biology of Golden Alga." Texas Parks and Wildlife, tpwd.texas.gov/landwater/water/environconcerns/hab/ga/bio.phtml. Accessed 22 Feb. 2018.

Feng, Jia, and Shulian Xie. "Numerical Taxonomy of Species in the Genus Mallomonas (Chrysophyta) from China." International Scholarly Research Notices Biodiversity, 2013, www.hindawi.com/journals/isrn/2013/653958/. Accessed 22 Feb. 2018.

Hao, Junxue, et al. "Morphology and Phylogenetic Placement of Mallomonas Vietnamica (Synurales, Chrysophyceae) from China." Journal of Oceanology and Limnology, 18 Mar. 2024, doi.org/10.1007/s00343-023-3124-3. Accessed 7 Nov. 2024.

"Mallomonas (Chrysophyceae)." University of New Hampshire, cfb.unh.edu/phycokey/Choices/Synurophyceae/MALLOMONAS/Mallomonas‗key.html. Accessed 22 Feb. 2018.

"Mallomonas." Encyclopedia of Life, eol.org/pages/11772/overview. Accessed 22 Feb. 2018.

Parker, Steve. Kingdom Classification: Protozoans, Algae, and Other Protists. Capstone, 2009.

Piątek, Jolanta, and Magdalena Łukaszek. "Mallomonas cronbergiae (Chrysophyceae, Stramenopiles), A New Species from the Guineo-Congolian Rainforest in Cameroon." Polish Botanical Journal, vol. 61. no. 2, 10 Dec. 2016, pp. 199–204.

Sandgren, Craig D. et al, editors. Chrysophyte Algae: Ecology, Phylogeny and Development. Cambridge UP, 1995. Siver, Peter A. "The Downsizing of Gigantic Scales and Large Cells in the Genus Mallomonas (Synurales, Chrysophyceae)." Scientific Reports, 22 Mar. 2022, www.nature.com/articles/s41598-022-09006-1. Accessed 7 Nov. 2024.

Van Vuuren, Sanet Janse. "Easy Identification of the Most Common Freshwater Algae." Department of Water and Sanitation, Republic of South Africa,2006, www.dwa.gov.za/iwqs/eutrophication/NEMP/Janse‗van‗Vuuren‗2006‗Easy‗identification‗of‗the‗most‗common‗freshwater‗algae.pdf. Accessed 22 Feb. 2018.