Diatomaceous earth mined from these deposits has a wide variety of important industrial uses as a filter and abrasive; some organic gardeners employ it for pest control. The diatom plastids are derived from red algal secondary symbiosis and are golden brown due to the high concentration of the carotenoid fucoxanthin. Journal History This article was published in the Botanical Gazette (1876-1991), which is continued by International Journal of Plant Sciences (1992-present). Their major role in primary productivity makes diatoms important in the global carbon cycle and in aquatic food chains; Diatomacous earth is widely used in commerce Description of Diatoms: It is a large group of algae consisting of 200 genera and over 10,000 species, out of which 92 genera and about 569 species are reported from India. If a victim has breathed in water, diatoms can enter their blood stream, bone marrow, brain, lungs and kidneys. Some ancient diatomaceous earth deposits that were once seafloor sediment are today dry land. Diatom plays an important in the ocean ecosystem because the production of 45 percent of organic materials is at the hand of diatoms. The organic casing is a key component of the cell wall, preventing silica dissolution in seawater ( … Algae - Algae - Ecological and commercial importance: Algae form organic food molecules from carbon dioxide and water through the process of photosynthesis, in which they capture energy from sunlight. Economic importance. Diatom test is an important tool in diagnosis death in drowning cases. Sometimes diatom shells in seafloor sediment can over time become diatomaceous earth. 3. The diatom cell wall is composed of two silica-containing halves each consisting of a valve connected to a series of overlapping girdle bands and coated by an organic matrix (Round et al., 1990). The study of diatom is included as a part of phycology. The diatomist is the phycologists who specialize to study diatom. Although there are periods when one diatom species has dominated the other, over the period as a whole, the two diatoms appear to be in a stable coexistence. These tiny organisms have been around for billions of years and play major roles in chemical and biological processes. As the typical features of ante-mortem drowning disappeared very rapidly with commencement of putrefaction and hence diatom test plays an important role for diagnosis and confirmation of drowning deaths. The diatoms in each deposit contain different amounts of silica, depending on the age of the deposit, and different deposits may even contain a different species of diatom all together. The species of diatom found in a deposit is dependant upon the age and paleo-environment of the deposit. If a person has drowned then diatoms are able to enter the human body. Facts about Diatoms 9: studying diatoms. 2. Large spring blooms of the planktonic diatoms Aulacoseira subarctica Haworth and Stephanodiscus astraea occur every year and are terminated by SiO2 depletion. They are commonly known as Diatoms. This diatom retains it eukaryotic nucleus, and little is known about the degree of genetic interdependence between the endosymbiont and host. The importance of diatoms must not be overlooked. The diatoms are the most beautiful microscopic algae due to their structure and sculpturing of their walls. Diatoms Images. Economic Importance. Diatoms are also useful in forensic studies.