Secchi Disk

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Secchi disk

[′sek·ē ‚disk]
An opaque white disk used to measure the transparency or clarity of seawater by lowering the disk into the water horizontally and noting the greatest depth at which it can be visually detected.

Secchi Disk


an instrument for measuring water transparency in a body of water. A white disk 30 cm in diameter, it is held horizontally and lowered into the water on a rope until it is no longer visible. The depth, in meters, at which it ceases to be visible is taken as a measure of the water transparency. The disk is named after A. Secchi, who measured the transparency of sea water by this method in 1865.

References in periodicals archive ?
12) In addition to the customary locational and structural variables, they use Secchi disk readings as an objective measure of water clarity.
Zooplankton samples were collected every month at five selected stations in the lake with three replicates, and the water temperature, dissolved oxygen, pH, Secchi disk depth, electrical conductivity, and depth were measured at the stations.
Secchi disk depth: A new theory and mechanistic model for underwater visibility.
In present work, the infestation rate decreases with increase in turbidity, and water clarity measured with Secchi disk showed positive relation to isopod infestation.
Field and laboratory methods used for different variables Variable Abbreviation Unit Physical and chemical variables Water level WL cm Secchi disk depth Secchi m Water surface Temp [degrees]C temperature Dissolved oxygen DO mg [L.
Drop a big white grub or spinnerbait (or a 12-inch Secchi disk if you have one) into the water and when you can no longer see it, measure this depth to the surface and double it.
1997) said that the remotely sensed data have widely been used to estimate major water quality variables such as chlorophyll-a, turbidity, suspended sediment concentration, Secchi disk depth, surface water temperature, wave height, and sea surface roughness.
Additionally, the Secchi disk transparency was determined in each occasion on each lake.
It is a proxy the scientific community has long accepted as legitimate, said Paul Falkowski of Rutgers University, who has used Secchi disk data for his work.
Two reservoir locations were monitored bi-weekly from May through September 2007 for pH, temperature, dissolved oxygen, Secchi disk transparency, chlorophyll a, and nutrients.