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TOOLS OF THE OCEANOGRAPHER: Equipment: Measuring tools

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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2. Salinity

Hydrometer (quick test type for aquariums)
	Measures: Salinity in parts per thousand (o/oo) Operates: By reading the density (specific gravity) of the water that corresponds to salinity. Increasing dissolved salts increase the density. Notes: Very easy to use this but it does not correct for density changes due to temperature.

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Hydrometer Set (cylinder, hydrometer, thermometer, TSD graph)

Measures: Salinity in parts per thousand (o/oo) Operates: With a water sample by using a hydrometer to measure the density of the water (water with more salt is more dense and will float the hydrometer higher in the cylinder) which can then be used along with the temperature in a standard TSD graph (temperature, salinity, density) to find the salinity since these three variables have a known relationship Notes: Very hard to do on a rocking boat but easy on solid land.

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Chemical Test Kit (Knudsen Titration modification) for Salinity
	Measures: Salinity in parts per thousand (o/oo) Operates: By a chemical titration with a water sample to determine just one of the salts (chloride ion) and extrapolate the rest of the salinity Notes: Not very accurate because of interaction of other salts

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Salinometer
	Measures: Salinity in parts per thousand (o/oo) Operates: By measuring the electrical conductivity and extrapolating (saltier water is a better conductor) Notes: Very accurate but also expensive ($200 or more)

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