1
2
Epipelagic Zone
3
5
Major Ocean Currents
Currents
4
Surface Winds
6
• The surface currents are caused by the
winds
• Only a small amount of energy is
transferred (2%), so even fast, hard winds
don’t get the currents moving too fast.
• But things don’t necessarily move in the
way you would expect…
1
7
Ekman Spiral
8
Upwelling
• Just like wind, water
is deflected by the
Coriolis effect
• As energy goes down,
water is bent towards
the right (in N. Hemisphere)
Coastal-
Equatorial
9
11
PELAGIC
ANIMALS
10
Figure 15.02
Deep Ocean Currents
12
2
13
The Microbial Web
14
Primary Productivity
• 6CO2 + 6H2O = C6H12O6 + 6O2
• With rare (relatively)
exceptions, all energy comes
into the system via this
pathway.
• Gross PP – respiration =
Net Production
• Many different measurement
techniques for PP
15
Phytoplankton Production
16
Physical- Light
• Variation in wavelengths through water
Compensation
Depth ≈ 1% surface
intensity
PARPhotosynthetically
Available Radiation
Count available
photons, not just all
wavelengths
What determines the productivity of an area? Two things…
17
18
Where does the light go?
• Light is Scattered by:
– Suspended particles (Sediment
“soil”, plankton, etc.)
– Dissolved material
Measuring Water Clarity
•Secchi Disk
•Other more complicated
methods
• Light is Absorbed by:
– Phytoplankton: used in
photosynthesis, converted to
chemical energy
– Water molecules: converted to heat
This scattering and absorption
impact the colors differently
3
19
20
• So…Why is the ocean blue?
– The rates of scattering and absorption are
LOWEST for blue, so blue light makes it down to
greater depths and is more available for reflecting
back to the surface.
Importance of light in the sea
• Sunlight absorbed by the water is converted to
heat.
– This heat warms the upper portions of the water.
– It also provides the energy for evaporation and the
winds.
• Photosynthesizing organisms (“plants”) are
the main source of the food in the ocean!
– The depth at which light penetrates the ocean
controls the depth to which these organisms can
occur.
– This zone is called the Photic Zone.
21
22
Other biological impacts of light
Intensity changes
With time of day
• Light influenced movement
With other biomass
– Daily Vertical Migration
With turbidity
• Many different groups of animals migrate up and
down in the water with the changing light intensity.
• They typically come up to the surface to feed at
night, then swim back down at dawn to escape their
predators.
• Many swim 100s of meters a night.
With season
• Coloration of animals
– In the open ocean there is no where to hide!
– Many animals have evolved interesting ways to
deal with this issue using color.
23
24
Seasonal Cycles in Primary Productivity
Winter
Spring
Summer
Fall
Seasonal Cycles in Primary Productivity
Winter
Spring
Summer
Fall
4
25
Seasonal Cycles in Primary Productivity
26
What is the midwater?
Land
Epipelagic
Ocean
surface
200 m
Continental shelf
Mesopelagic
1000 m
Continental
slope and rise
• All pelagic or open
water environments
Bathypelagic
4000 m
Abyssopelagic
Abyssal plain
6000 m
• Largest and least
known habitat on
earth!
27
Hadalpelagic
Trench
10,000 m
28
Oxygen
Minimum
Zone
29
Deepsea Fish
30
5
31
Avoiding Predation
32
Feeding
There is nowhere to hide!
•
•
•
•
•
•
33
Big and/or Mean...
35
34
…or Small...
36
…or Hidden!
Be big/mean or small/hidden
Transparency
Bioluminescence
Mucus
Counter-shading
Low Carbon value
Counter Shading
6
37
38
Counter shading
Bioluminescence
?
?
?
39
40
?
41
Coelenterazine
42
Bioluminescence
“Milky Seas”
General reaction
•Communication
•Protection
Dinoflagellate
•Hiding
•Hunting
Photoproteins- modify/control the reaction
Firefly
7
43
Dark Guts to Hide
Luminescent Prey
44
“Burglar Alarm” Hypothesis
8