Read through the notes below or on-line and answer the questions 1-11 from the notes.
I. Ocean Temperature & Productivity

Interaction of solar radiation with ocean water governs ocean temperature, marine productivity, and the color of seawater

92% of visible solar radiation that hits the ocean surface is absorbed.

65% of the visible light that does enter seawater is absorbed within the upper 1 m (3.3 ft) and no more than 1% reaches a depth of 100 m (330 ft)

Seawater temperature declines with increasing latitude and increasing depth
A. 3 Layers of the Oceans - permanent layers based on the vertical profile of average water temperature:
1. Mixed layer - winds circulate ocean surface waters down to a max depth of about
450 m (1475 ft) at mid latitudes; temperature averages about 15 0C (59 0F)
2. Main Thermocline - transition zone between the warmer water of the mixed layer
& the colder water of the deep layer
3. Deep Layer - occurs below a depth of
1200 m or (3900 ft) in mid latitudes; usually under 4 0C (39 0F); extends to the surface at latitudes above 50 0 N or S
Therm = temperature cline = rapid change with depth
B. Photic Zone - the sunlit upper layer
that receives adequate light for
photosynthesis; area where algae grows.
C. Aphotic Zone - area below the photic
zone where too little light penetrates for
plants to survive.
D. Ocean Color is caused by water absorbing longer wavelengths of visible light (red
& yellow) so green & blue penetrate to greater depths. Near shore shallow water
tends to have more suspended material which scatters more green & yellow giving
the shore area a slightly lighter color.

II. Thermohaline Circulation - subsurface movements of water masses, generated by density contrasts that arise from differences in temperature & salinity
* Heat transport by moving water masses -likened to conveyor belts- is an important control of global climate. http://rainbow.ldgo.columbia.edu/ees/climate/slides/belt.gif
A. Water Mass - a large volume of seawater that is relatively uniform in density and is identifiable based
on its temperature, salinity, and other properties.

A water mass of greater density (colder and/or more saline) will displace and flow beneath a water mass of lesser density

Thermohaline circulation involves about 90% of all ocean water, but oceanographers know less about it than surface currents because studying deep-ocean circulation is expensive & time-consuming.

Flow of water masses is very slow and hard to measure.

1000 years or more may pass before water generated at a high colder latitude returns to the surface.

Oceanographers classify water masses by the depth at which they reach equilibrium with their surroundings and their geographical source region.
Name Designation by
Depth
Central Waters
Intermediate Waters
Deep & Bottom Waters
Name Designation by Source
Atlantic Water
Pacific Water
Indian Water

Water mass A and water mass B have different temperatures and salinities but the same density as plotted in Figure 8.5 to the right.

When these two water masses mix in equal proportions, the temperatures average and the density changes as shown by C.

Mixing of two water masses having the same density results in a new water mass of greater density, this is called caballing.
Fig. 8.5


Lines of constant density are called isopycnals , notice the lines are curved not straight.
B. Properties of Some Water Masses
1. Antarctic Bottom Water (AABW)
highest temperature-salinity related
density of any ocean;
approximately 750 years old
2. Mediterranean Intermediate
Water
(MIW) - high salinity (36.5psu) and
warm water.
3. Pacific Common Water (CoW) -
Antartic bottom water mixed with
North Atlantic Deep water;
approximately 1500 years old
4. Red Sea Intermediate Water
(RSIW)
- moves over the submarine sill at
the Strait of Babel Mandeb
& into the Indian Ocean at a depth of
about 3 km; exceptionally high
salinity (greater than 40psu)
produced by extreme evaporation
III. Ocean Bottom
 Parts of the ocean bottom are volcanically active, but most of the ocean bottom is unchanged geologically except for sediments falling from above.

Mapped & studied with sonar & satellites
A. Continental Margin
1. Continental Shelf - zone closest to the beach; gentle slope, nearly flat, out to a depth of about 200 m
(655 ft); widest where shelf is passive (no plate boundary nearby) Ex. North American Continental
Shelf is wider on the east coast. Most of the world's fisheries are confined to the continental shelf.
2. Continental Slope - Steeply sloping zone; has deep submarine canyons; area where continental
crust changes to oceanic crust.
* Submarine Canyons - steep-sided slices in the continental slope believed to be caused by turbidity
currents; cut by rivers such as the Hudson River during the Ice Age
* Turbidity Currents – fast down-slope flow of water heavily laden with suspended sediment from
rivers; denser than normal seawater; resembles an underwater avalanche; powerful agent of
erosion
3. Continental Rise - transition between steep slope and flat ocean bottom
* Submarine Fans - accumulated sediments at the bottom of the Continental Rise

B. Ocean Basin - average depth is 3800 m (12,500 ft); topography varies
1.
Flat Abyssal Plains – covered in sediments a.
Oozes – sediments made from microscopic shells. b.
Muds & Clays c.
Turbidites – deposits made by Turbidity currents that have been swept down the submarine canyons & out onto the abyssal plain d.
Authigenic Sediments – sediments that did not fall to the ocean floor but formed in place directly on the seafloor. Ex. Manganese nodules
2. Deep Trenches - formed where one plate submerges under another; Ex Mariana Trench, Peru-Chile
trench
3. Seamounts - formed by significant underwater volcanic peaks rising more than 1000m (3300 ft)
above the ocean floor; the Hawaiian Islands are seamounts that got so large they extend beyond the
ocean surface
4. Guyots {GHEE ohs} - flat-topped seamounts
5. Coral Atoll - a ring-shaped island surrounding a seawater lagoon; formed as coral built up around an
island as the island was sinking
6. Submarine Mountain Ranges - Mid-ocean ridges form on either side of the rift zone where the plates
are pulling apart Ex. Mid Atlantic Ridge

Questions:
Fill in or circle the correct response. Use your notes as a reference.
1.
The [(aphotic zone) (photic zone)] refers to the top most layer of ocean water where sunlight penetrates enough for photosynthesis to occur.
2.
The [(mixed layer) (main thermocline) (deep layer)] is closest to the ocean surface in most areas.
The [(mixed layer) (main thermocline) (deep layer)] reaches the surface at latitudes above 50 0 .
3.
[(Therm) (Cline)] refers to a rapid change in depth in the meaning of the word thermocline.
4.
Ocean color is slightly [(lighter) (darker)] near the shore or shallow areas where suspended materials make the water more turbid and scatter more [(red & blue) (blue & green) (green & yellow)] light.
5.
Deep water ocean circulation has been compared to a _____________________________ .
6.
Pacific Common Water CoW is approximately [(150) (1,500) (15,000)] years old.
7.
You can interpret from the diagram on atolls that subsidence means [(increasing) (decreasing)] .
8.
When two water masses with the same [(density) (salinity)] but different [(density) (salinity)] meet their density [(increases) (decreases)] according to Figure 8.5 T-S diagram.
9.
The Hawaiian Islands are an example of an ocean basin feature called [(atolls) (guyots)
(seamounts)] .
10.
[(Ocean currents ) (Turbidity currents)] are one of the causes of damage to deep sea communication cables because they carry quickly moving sediments downhill that can snap the cables.
11.
[( Isobars ) ( Isopycnals )] are lines of constant ocean density.
SEAWATER TEMPERATURE, PRESSURE, AND SURFACE OCEAN CURRENTS
In this part of the investigation we take a closer look at the relatively warm Gulf Stream that forms the western arm of the North Atlantic gyre. Our primary source of sea-surface temperatures (SSTs) of the Gulf
Stream and surrounding ocean is infrared sensors flown aboard satellites.
Image 1 and Image 2 are supplied by the Naval Atlantic Meteorology and Oceanography Center (NLMOC) located in Norfolk, VA. The images are overlapping maps on which are plotted SSTs in °C obtained on 29
October 2001. * Combined, the maps cover the Gulf of Mexico and the Atlantic Ocean along the East Coast of North America. To produce a single continuous map, cut your paper copy of Image 1 along the 35-degree latitude line, place Image 1 over Image 2 where the two maps match, and then secure with tape along the left margin of Image 1 and on the back side.
1.
Starting at the southern tip of Florida use a pencil to shade the location of the Gulf Stream. Relatively high sea-surface temperatures delineate the Gulf Stream on this analysis (by the Naval
Oceanographic Office). Two roughly parallel solid and dashed black lines enclose the Gulf Stream, labeled “GS.” The Gulf Stream parallels the coast from Florida to North Carolina and then turns northeastward and eastward.

2.
*At home: Color-code the ocean surface to indicate relative temperature. Use dark blue for the shelf water “SHW” along the Northeast coast, light blue for the slope water “SLW,” dark red for the Gulf
Stream “GS,” and light red for the Sargasso water “SAR” south and east of the Gulf Stream.
3.
Along Florida’s East Coast, the highest sea-surface temperature in the Gulf Stream is ______ °C.
4.
Several heavy black arrows indicate the direction of flow of the Gulf Stream. Looking in the direction of the flow, the coldest surface water is to the [(right) (left)] of the Gulf Stream.
5.
According to the analysis in Images 1 and 2, the greatest speed of the Gulf Stream waters is
[(0.5)(1.3)(1.7)] KTS (knots or nautical miles per hour).
6.
Warm eddies “WE” are located on the
[(cold) (warm)] water side of the Gulf Stream. No cold eddies
“CE” appear on this analysis. If they were present, cold eddies would be on the
[(cold) (warm)] water
side of the Gulf Stream.
7.
Shelf water “SHW” and slope water “SLW” are located
[(just east of the Gulf Stream) (between the
coast and the Gulf Stream)] . Shelf water has surface temperatures that are among the [(lowest)
(highest)] on the map
Image 3 and Image 4 are also supplied by the Naval Atlantic Meteorology and Oceanography Center
(NLMOC) located in Norfolk, VA. The images are overlapping maps as well but for 11 February 2001.
Repeat the process from above* to make the most recent map of the Gulf Stream.
8. Along Florida’s East Coast, the highest sea-surface temperature in the Gulf Stream is ______ °C. On
the February map the temperatures of the Gulf Stream off Florida tend to be [(much colder) (much
warmer) (slightly colder) (slightly warmer)] than the October map.
9. As with the previous map the coldest surface water is to the [(right) (left)] of the Gulf Stream.
10. According to the analysis in Images 3 and 4, the greatest speed of the Gulf Stream waters is
[(0.5)(1.2)(1.7)] KTS (knots or nautical miles per hour). This is [(slower) (faster)] than the speed in
October.
11. Depending on whether you have a color or black/white copy of Image 5 , bands of color or shades of
gray represent satellite-derived SSTs. The scale of color-coded SSTs (in °C) appears along the right
margin of the image. While the latest Image 5 view available typically lags the most recent NLMOC
maps by several days, they can be compared because of the relatively slow response of the ocean to
change. Whether you are looking at color or black/white images, note the western boundary of the
Gulf Stream located east of Central Florida to Cape Hatteras, NC, and beyond. The boundary in
Image 5 [(is) (is not)] generally consistent with the boundary depicted in the map delivered in Images
3 and 4.
12. Go to http://library.thinkquest.org/22254/inventions.htm
. Scroll down and find out two ways Ben
Franklin contributed to Earth Science. _________________________________ &
_____________________________________