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Nitzschia Pusilla
''Nitzschia'' is a common pennate marine and freshwater diatom. In the scientific literature, this genus, named after Christian Ludwig Nitzsch, is sometimes referred to incorrectly as ''Nitzchia'', and it has many species described, which all have a similar morphology. In its current circumscription, ''Nitzschia'' is paraphyletic. Occurrence ''Nitzschia'' is found mostly in colder waters, and is associated with both Arctic and Antarctic polar sea ice Sea ice arises as seawater freezes. Because ice is less density, dense than water, it floats on the ocean's surface (as does fresh water ice). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world' ..., where it is often found to be the dominant diatom. ''Nitzschia'' includes several species of diatoms known to produce the neurotoxin known as domoic acid, a toxin responsible for the human illness called amnesic shellfish poisoning. The species ''N. frigida'' is found to grow exponent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microfossil
A microfossil is a fossil that is generally between 0.001 mm and 1 mm in size, the visual study of which requires the use of light or electron microscopy. A fossil which can be studied with the naked eye or low-powered magnification, such as a hand lens, is referred to as a macrofossil. Microfossils are a common feature of the geological record, from the Precambrian to the Holocene. They are most common in deposits of marine environments, but also occur in brackish water, fresh water and terrestrial sedimentary deposits. While every kingdom of life is represented in the microfossil record, the most abundant forms are protist skeletons or microbial cysts from the Chrysophyta, Pyrrhophyta, Sarcodina, acritarchs and chitinozoans, together with pollen and spores from the vascular plants. Overview A microfossil is a descriptive term applied to fossilized plants and animals whose size is just at or below the level at which the fossil can be analyzed by the naked e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
