The Ocean Environment (Topic 2A) – page 1
The Ocean Environment Lecture Notes
Density
Floating
Sinking Slow
Filter Feeding / Suspension Feeding
1. True or false? “Filter/Suspension feeders wait for food to come to them.”
2. True or false? “Filter/Suspension feeders live on the sea floor;
they do not swim or drift in the water.”
3. Which of the following are examples of “filter feeding” or “suspension feeding”?
(Circle all that apply.)
● catching plankton that are drifting by in a mucus “net”
● grabbing drifting plankton out of the water using tentacles
● picking through sediments, looking for something good to eat
● preferred food (e.g., crustaceans) is separated from the other food (e.g., worms),
which is thrown away
● pumping water through gill slits or baleen – water goes through
but plankton are caught
● sitting in one spot and waiting to catch fish that swim by
The Ocean Environment (Topic 2A) – page 2
Reproduction
Ocean Water Temperature
Viscosity
Oxygen
Nutrients
Salinity
The Ocean Environment (Topic 2A) – page 3
Sound
Suppose a ship emits a sound (“ping”), and 4 seconds later the ship receives the echo of the original
sound. In other words, it takes 4 seconds for the sound to travel to the bottom of the ocean and then
return to the surface as an echo. Sound travels through water (about 1500 meters per second).
About how deep is the ocean at this location?
Pulse
CTD
&
Sample
Bottles
Echo
Ship
Ocean Bottom
The Ocean Environment (Topic 2A) – page 4
The Cause of Atmospheric Pressure and Hydrostatic Pressure
Pressure is, of course, caused when something presses against something else. In this class, we
will primarily discuss atmospheric pressure and hydrostatic ocean pressure which are caused by
the weight of the air and/or ocean water above. The basic rule is this: the more stuff (air or water)
there is above, the higher the pressure, because the more stuff there is, the heavier it will be.
We hardly notice the effects of air pressure, because our bodies are built to tolerate it; it is
“normal” for us. Water, of course, is much heavier than air. Every 10 meters (33 feet) of water
that is above your head is equivalent to the weight of the entire atmosphere.
Note: Sound waves are vibrations – fluctuations – in pressure. So, sound wave slightly increase
or decrease the pressure caused by the weight of the air and water about ocean organisms. Many
organisms can feel these vibrations all along their bodies, not just in their ears or similar organs.
4. Consider the following statement:
“The pressure that a SCUBA diver experiences while diving
is caused by the high density of the air above them.”
What is incorrect or misleading about this statement?
5. One way to measure pressure is in terms
of “atmospheres.” 1 atm (atmosphere)
of pressure is the weight of the air
above at sea level.
How many atm of pressure does each
diver experience in the picture on the
right experience? Write down the
pressure in atm next to each diver.
Atmospheric Pressure and Storm Surge
Storm
Air
Molecules
Land
Ocean
Land
10 meters
A
20 meters
Ocean
B
30 meters
C
The Ocean Environment (Topic 2A) – page 5
Light and the Color of Objects
The color that an objects has depends upon both the atoms and molecules the object is made of
AND the kinds of light shining on it.
Sunlight includes ALL the colors of the rainbow (e.g., red, orange, yellow, green, blue, purple).
However, our eyes only tell us about the strongest color of light coming from an object. We
perceive the Sun as being yellow, because the Sun emits (creates) more yellow light than any
other color. Other hot objects like fire and light bulbs also emit all the colors of the rainbow, but
may emit some more than others.
Each substance absorbs some colors of light, and reflects other colors (they “bounce off”). As
you can see from the picture on the right, we see the color of light that reflects off the object
most strongly. So, in the example on the right, the
person looking at the shirt perceives it as being
“red” because mainly red light is reflecting off the
shirt while other colors of light like yellow and blue
are being absorbed. The colors of light that are
absorbed warm the object. (Think of the light
energy as being transformed in heat energy.)
6. If your eyes absorb:
5% red light
15% orange light
15% green light
5% blue light
60% yellow light
What color do you see?
7. When orange light hits a yellow animal, is it absorbed or reflected?
8. When orange light hits an orange animal, is the light absorbed or reflected?
9. When orange light hits a white animal, is the light absorbed or reflected?
10. When orange light hits a black animal, is the light absorbed or reflected?
The Ocean Environment (Topic 2A) – page 6
Why Does the Ocean Look Blue?
11. Standing on the Shore:
Blue light is the most abundant color of light going into
your eyes because it tends to be _____________________
when it hits ocean water. The other colors are more likely to
____________________________ when they strike ocean water.
12. Beneath the Surface, Looking Up:
Blue light is the most abundant color of light going into your eyes
because it tends to ____________________________ more slowly
by water than the other colors of light. Blue is “left over” when
the others are gone.
Possible Answers: be absorbed, go straight, scatter (reflect)
13. Beneath the Surface, Looking to the Side:
Blue light is the most abundant color of light going into your
eyes because it tends to ______________________________
when it hits ocean water. The other colors are more likely to
___________________________ when they strike ocean water.
Possible Answers: be absorbed, go straight, scatter (reflect)
14. What if there was no blue light in sunlight?
What color would the ocean be: red, orange, yellow, green, or blue? Why? Explain.
15. What if yellow light was absorbed faster by water than any other color of light?
What color would the ocean be: red, orange, yellow, green, or blue? Why? Explain.
16. What if red light “scattered” more strongly off water molecules than any other color of
light? What color would the ocean be: red, orange, yellow, green, or blue? Why? Explain.