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Diatoms are used to monitor past and present environmental conditions, and are commonly used in studies of water quality. Diatomaceous earth (diatomite) is a collection of diatom shells found in the Earth's crust.
Diatomite rock sample from Sisquoc Formation Scanning electron micrograph of diatomaceous earth. Diatomaceous earth (/ ˌ d aɪ. ə t ə ˈ m eɪ ʃ ə s / DY-ə-tə-MAY-shəs), also known as diatomite (/ d aɪ ˈ æ t ə m aɪ t / dy-AT-ə-myte), celite, or kieselguhr, is a naturally occurring, soft, siliceous sedimentary rock that can be crumbled into a fine white to off-white powder.
Diatomaceous earth filtration is a special filtration process that removes particles from liquids as it passes through a layer of fossilized remains of microscopic water organism called diatoms. These diatoms are mined from diatomite deposits which are located along the Earth's surface as they have accumulated in sediment of open and moving ...
Forensic limnology is a sub-field of freshwater ecology, which focuses especially on the presence of diatoms in crime scene samples and victims. Different methods are used to collect this data but all identify the ratios of different diatom species present in samples and compare those samples with the location of a crime scene.
A frustule is the hard and porous cell wall or external layer of diatoms. The frustule is composed almost purely of silica, made from silicic acid, and is coated with a layer of organic substance, which was referred to in the early literature on diatoms as pectin, a fiber most commonly found in cell walls of plants.
For many years the diatoms—treated either as a class (Bacillariophyceae) or a phylum (Bacillariophyta)—were divided into just 2 orders, corresponding to the centric and the pennate diatoms (Centrales and Pennales; alternative names Biddulphiales and Bacillariales, as used e.g. in Lee, 1989). [9]
Diatoms in both fresh and salt water extract dissolved silica from the water to use as a component of their cell walls. Likewise, some holoplanktonic protozoa , some sponges, and some plants (leaf phytoliths) use silicon as a structural material. Silicon is known to be required by chicks and rats for growth and skeletal development.
Diatoms are used to as a diagnosis tool for drowning in forensic practices. The diatom test is based on the principle of diatom inhalation from water into the lungs and distribution and deposition around the body. DNA methods can be used to confirm if the cause of death was indeed drowning and locate the origin of drowning. [37]