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Silicon enters the ocean in a dissolved form such as silicic acid or silicate. [103] Since diatoms are one of the main users of these forms of silicon, they contribute greatly to the concentration of silicon throughout the ocean. Silicon forms a nutrient-like profile in the ocean due to the diatom productivity in shallow depths. [103]
Siliceous organisms in the ocean, such as diatoms and radiolaria, are the primary sink of dissolved silicic acid into opal silica. [32] Only 3% of the Si molecules dissolved in the ocean are exported and permanently deposited in marine sediments on the seafloor each year, demonstrating that silicon recycling is a dominant process in the oceans. [3]
Because the ocean floors are mainly sima, it is also sometimes called the 'oceanic crust'. The name 'sima' was taken from the first two letters of silica and of magnesia . Comparable is the term sial (another antiquated blended term), [ 2 ] which is the name for the upper layer of Earth's crust ( continental crust ) , namely rocks rich in ...
Winds drive ocean currents in the upper 100 meters of the ocean's surface. However, ocean currents also flow thousands of meters below the surface. These deep-ocean currents are driven by differences in the water's density, which is controlled by temperature (thermo) and salinity (haline). This process is known as thermohaline circulation.
Earth's inner core is the innermost geologic layer of the planet Earth. It is primarily a solid ball with a radius of about 1,220 km (760 mi), which is about 20% of Earth's radius or 70% of the Moon's radius. [1] [2] There are no samples of the core accessible for direct measurement, as there are for Earth's mantle. [3]
Scientists believe they’ve discovered an ancient ocean floor comprising a new layer between Earth’s mantle and core.
The remaining opal silica is exported to the deep ocean in sinking particles. [11] In the deep ocean, another 26.2 Tmol Si Year −1 is dissolved before being deposited to the sediments as opal silica. [11] At the sediment water interface, over 90% of the silica is recycled and upwelled for use again in the photic zone. [11]
For example, microscopic particles of silica called phytoliths can be found in grasses and other plants. Silica is an amorphous metalloid oxide formed by complex inorganic polymerization processes. This is opposed to the other major biogenic minerals, comprising carbonate and phosphate , which occur in nature as crystalline iono-covalent solids ...