CH21 Ocean Water
Mrs. Kummer
Earth Science, Fall 2014
Properties of Ocean Water
1.
2.
3.
4.
5.
6.
Dissolved gases
Dissolved solids
Salinity
Temperature
Density
Color
KidsGeo.com. Web. 1 Jul 2011.
<http://www.kidsgeo.com/geography-for-kids/0142-oceantemperatures.php>.
Dissolved Gases
• 3 gases make up atmosphere
(air)
– Nitrogen (N2)
– Oxygen (O2)
– Carbon Dioxide (CO2)
• 3 gases dissolved in ocean
water
– Carbon Dioxide (CO2) is most
easily dissolved in ocean water
– Oxygen (O2)
– Nitrogen(N2)
Dissolved Gases
• Gases enter at rivers, streams, volcanic
eruptions, and organisms living in ocean
Dissolved Gases
• Temperature affects amount of gases dissolved
– Colder water  gases dissolve better, held longer
– Warmer water gases don’t dissolve as easily
• Oceans contain 60 times more carbon than
atmosphere
• Oceans called “carbon sink” – can trap CO2 for
hundreds to thousands of years
Dissolved Solids
• Six Solids found in ocean water: Cl, Na, Mg, S,
Ca, K
• Sea salts = 3.5% mass of ocean water
Dissolved Solids
• Halite (Sodium & Chlorine) make up 85% of
dissolved solids
Dissolved Solids
• Sources of sea salts:
1. Volcanic eruptions
Dissolved Solids
2. Chemical weathering of land rock
Dissolved Solids
3. Chemical reactions between sea water & newly
formed sea-floor rocks
Salinity
• Measure of amount of dissolved salts in 1kg of
ocean water
• Average salinity is 3.3% to 3.6%
• So, if you evaporate out 1000 grams of water
from the ocean, 35 grams of salt would
remain
Salinity
Factors that change salinity:
– Rate of evaporation is higher than precipitation,
salinity increased
– Polar waters have low evaporation, melting of ice
from sunlight, numerous rivers leading to low
salinity
Salinity
• Can vary greatly depending on location
– Red Sea has hot & dry climate = high salinity
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- zone of rapid temperature
change
• 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
Density
• Remember from Week#2, ρ=m/V
• 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
– Cold water is constantly sinking to bottom of
ocean
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-oceanspray-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 forms off of New Zealand because
of abundant food sources.
"Plankton bloom off Waiheke Island." Web. 1 Jul 2011. <http://www.teara.govt.nz/en/plankton/1/4>.
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.
Divisions of the Marine Environment
I. Pelagic (open sea)
– Neritic (< 200 meters) and oceanic
II. Benthic (sea floor)
– Subneritic and suboceanic
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Pelagic Environment
• Divided into biozones
1. Neritic Province – from
shore seaward, all
water < 200 meters
deep
2. Oceanic Province –
depth increases
beyond 200 meters
© 2011 Pearson Education, Inc.
Oceanic Province
• Further subdivided into four biozones
1. Epipelagic
a) Only zone to support photosynthesis
b) Dissolved oxygen decreases around 200 meters
2. Mesopelagic
a) Organisms capable of bioluminescence common
3. Bathypelagic
4. Abyssopelagic
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Ocean Zones Based on Light
Availability
I. Euphotic – surface to where enough light
exists to support photosynthesis
II. Disphotic – small but measurable quantities
of light
III. Aphotic – no light
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Benthic Environments
I. Supralittoral
II. Subneritic
1. Littoral
2. Sublittoral
a)
b)
Inner
Outer
III. Suboceanic
1. Bathyal
2. Abyssal
3. Hadal
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Organisms of the Deep
© 2011 Pearson Education, Inc.