ocean water: 20.1
DESCRIPTION
This ocean presentation is made for an 8th grade Earth Science class.TRANSCRIPT
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.