ocean water: 20.1

Ocean Water

Earth Science20.1

8th grade

Properties of Ocean Water

1. Dissolved gases2. Dissolved solids3. Salinity4. Temperature5. Density 6. Color

KidsGeo.com. Web. 1 Jul 2011. <http://www.kidsgeo.com/geography-for-kids/0142-ocean-temperatures.php>.

Dissolved Gases

• 2 gases make up atmosphere – Nitrogen (N2) & Oxygen (O2)

• 3 gases dissolved in ocean water– O2, N2, CO2, & other trace gases

Web. 1 Jul 2011. <http://eesc.columbia.edu/courses/ees/climate/lectures/greenhouse.html>.

Dissolved Gases

• Gases enter at rivers, streams, volcanic eruptions, and organisms living in ocean

Web. 1 Jul 2011. http://rst.gsfc.nasa.gov/Sect17/Sect17_4.html.

Dissolved Gases

• Temperature affects amount of gases dissolved– Colder water = gases dissolve better, held longer

• Oceans contain 60 times more carbon than atmosphere

• Oceans called “carbon sink” – can trap CO2 for hundreds to thousands of years

Dissolved Solids

• Sea salts = 3.5% mass of ocean water

• Most abundant elements:– Chlorine, sodium, magnesium, sulfur, calcium,

potassium

Dissolved Solids

• Salt Halite (Sodium & Chlorine) make up 85% of dissolved solids

"Dead Sea." Web. 1 Jul 2011. <http://en.wikipedia.org/wiki/File:Dead_Sea-18.jpg>.

Dissolved Solids

• Sources of sea salts:1. Volcanic eruptions

DiscoveryChannel.com. Web. 1 Jul 2011. <http://dsc.discovery.com/news/2008/06/12/underwater-volcano.html>.

Dissolved Solids

2. Chemical weathering of land rock

Web. 1 Jul 2011. <http://en.wikipedia.org/wiki/File:Abiskorock.JPG>.

Dissolved Solids

3. Chemical reactions between sea water & newly formed sea-floor rocks

Web. 1 Jul 2011. <http://earthobservatory.nasa.gov/Features/CarbonCycle/page2.php>.

Salinity

• Measure of amount of dissolved salts in a given amount of liquid

• Average salinity is 3.3% to 3.6%

Salinity

• Factors that change salinity:– Rate of evaporation is higher than precipitation,

salinity increased– Polar waters have high evaporation = high salinity

Salinity

• Can vary greatly depending on location– Red Sea has hot & dry climate = high salinity

Web. 1 Jul 2011. <http://en.wikipedia.org/wiki/File:Wiki_plot_04.png>.

Temperature

• Varies with depth & location• Affected by solar energy• Colder near poles – Pack ice or floating ice covering top 5 meters of

ocean surface– Insulates water below & prevents freezing

"Climatology SST." Web. 1 Jul 2011. <http://www.nationalatlas.gov/articles/mapping/a_avhrr.html>.

Temperature

• Thermocline- temperature drops with increased depth– Water near surface is less dense so heats better

but doesn’t mix well with below layers

• Colder water = more dense– Controls the movement of deep ocean currents– Holds more dissolved gases than warmer

Web. 1 Jul 2011. <http://www.windows2universe.org/earth/Water/temp.html>.

Density

• Mass ÷ volume (love formula)

• Factors that effect density of ocean water:1. Salinity (more salt = more dense)2. Temperature (colder = more dense)

• Densest water is found in polar regions– High salinity = more particles/mL

Color

• Determined by way it absorbs or reflects sunlight

• Water absorbs most colors of visible light• Blue wavelengths are reflected

"The Tube." Flickr. Web. 1 Jul 2011. <http://www.flickr.com/photos/mistybushell/2161046983/>.

"Vibrant Orange Sunrise Ocean Spray ." Web. 1 Jul 2011. <http://paulbates.com/vibrant-orange-sunrise-ocean-spray-pictures-photos/>.

Color• Importance– Substances or organisms can effect color• Ex.) phytoplankton (absorbs red/blue but

reflects green)– Scientists can determine the health of the ocean• Phytoplankton present = healthy ocean

"Plankton bloom off Waiheke Island." Web. 1 Jul 2011. <http://www.teara.govt.nz/en/plankton/1/4>.

Plankton forms off of New Zealand because of abundant food sources.

Textbook Resource

• Allison, Ph.D., Mead A., Arthur T. DeGaetano, Ph.D., and Jay M. Pasachoff, Ph.D. Earth Science. Austin, Texas: Holt, Rinehart, and Winston, 2008. 26-45, 754-767. Print.