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TOOLS OF THE OCEANOGRAPHER: Equipment: Measuring tools: Visibility

B.  Taking Measurements of the Marine Environment
1. Temperature • Standard Thermometer • Bucket Thermometer • Reversing Thermometer (for Nansen Bottle) • Bathythermograph (BT)	2. Salinity • Hydrometer (quick test type for aquariums) • Hydrometer Set • Chemical Test Kit (Knudsen) • Salinometer
3. Oxygen • Chemical Test Kit (Winkler Titration) • Dissolved Oxygen Probe	4. pH • pH test strips • Chemical Test Kit • pH meter
5. Visibility & Color • Secchi Disk (used by itself) • Forel/Ule Scale (used with the Secchi disk)	6. Other • There are chemical tests for numerous dissolved substances including Carbon Dioxide, Nitrogen, Phosphates, Ammonia, Lead, Copper and Manganese
7. Depth & Profile • Sounder (lead line) • Fathometer •Surveying Equipment	8. Currents • Current Meter • Dye • Drogues • Drift Bottles • Drift Cards

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5. Visibility & Color

Secchi Disk
	Measures: Visibility (vertical) Operates: By hand on a line to the depth where it becomes invisible Notes: May be hard for the viewer to be exact but a good approximation

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Forel/Ule Scale
	Measures: Color of the water (in roman numerals associated with colors from brown to green to blue) Operates: As a color comparator with the use of the secchi disk lowered to one meter for background so the color of the bottom won't interfere Notes: Can be hard for the viewer to choose the exact color

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