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What Is Glasslike Algae?

Algae are a large and varied group of mainly aquatic organisms. Most of them produce oxygen through photosynthesis and are responsible for much of the earth's oxygen supply. One particular member of the class Bacillariophyceae is the diatom. Diatoms are unicellular algae whose outer shells, partially composed of silica, gives them a glasslike appearance.

Biology
- Diatoms are distinct among single-celled, photosynthetic aquatic organisms for having nuclei and for the ability to develop complex outer cell walls called frustules. Frustules have patterns of pores and may be either bilaterally or radially symmetrical. There are over 10,000 known different species of diatoms which are identified by the intricate structures of these frustules. Diatoms can reproduce either asexually or sexually, while some may go through a resting spore phase.
Background
- Because silica contained in the frustules is easily preserved, the fossil record of diatoms is extensive. Some specimens date back over 135 million years to the Cretaceous Period. Scientists can use fossilized diatoms to gain insight into environmental conditions and climate cycles of the past. Diatomite is a type of soil composed of mainly fossilized diatom frustules. It appears as a chalky white deposit and is mined for use as an abrasive in such products as bathtub cleansers and toothpaste. It is also used for water filters, as the microscopic pores in the frustules act as sieves that can capture tiny bits of sediment.
Range and Habitat
- Diatoms are the most numerous of all algae and are found in freshwater and saltwater habitats all over the world. Depending on the nutrient content, almost all bodies of water in all parts of the world contain diatoms. Many are planktonic and move with the water, while others are attached to surfaces that remain underwater. They can even be found on ice floes. Some species of diatom are also found on land, living in mosses and very moist soils.
Envirommental Importance
- Diatoms are among the most abundant types of phytoplankton and as such are a vital part of the carbon fixation process. That is, they remove carbon dioxide from the atmosphere and convert it into a usable organic carbon that provides energy for life forms farther up the food chain. Some scientists estimate that diatoms are responsible for 20 to 25 percent of carbon fixation worldwide. Diatoms are also considered a good indicator species for toxins and pollutants in the water.

Animals & Science