1. Chapter 14 Animals of the Pelagic Environment
Essentials of Oceanography
7th Edition

2. Pelagic organisms Organisms that live in the pelagic environment:
Live suspended within the water column
Can float or swim
Have adaptations that allow them to stay above the ocean floor

3. Staying above the ocean floor
Adaptations for staying above the ocean floor:
Rigid gas containers
Swim bladder
Ability to float
Swim bladder
Figure 14-2
Gas containers in cephalopods
Figure 14-1

4. Microscopic floating organisms: Radiolarians
Radiolarians produce a hard test composed of silica
Tests have projections to increase surface area
Figure 14-3

5. Microscopic floating organisms: Foraminifers
Foraminifers produce a hard test composed of calcium carbonate
Test is segmented or chambered
Figure 14-4

6. Microscopic floating organisms: Copepods
Copepods have a hard exoskeleton and a segmented body with jointed legs
Relatives of shrimp, crabs, and lobsters
Figure 14-5

7. Macroscopic floating organisms: Krill
Krill are related to copepods but are larger in size
Abundant in Antarctic waters, where they are a favorite food of the largest whales
Figure 14-6

8. Macroscopic floating organisms: Coelenterates
Coelenterates are soft-bodied organisms including:
Siphonophores (Portuguese man-of war)
Scyphozoans (jellyfish)
Figure 14-7a

9. Swimming organisms (nekton)
Larger pelagic organisms can swim against currents and often migrate long distances
Nektonic organisms include:
Squid
Fish
Marine mammals

10. Squid
Squid are invertebrates that swim by taking water into their body cavity and forcing it out through their siphon
Figure 14-8

11. Fish: Swimming motions and fins
Figure 14-9

12. Fish: Adaptations Feeding styles: Lungers versus cruisers
Lungers sit and wait for prey to come close by
Cruisers actively seek prey
Cold-blooded versus warm-blooded
Most fish are cold-blooded
A few active fish are warm-blooded
Many fish school to avoid predators

13. Fish: Deep-water nekton
Adaptations of deep-sea fish:
Good sensory devices
Bioluminescence
Large, sharp teeth
Large mouths and expandable bodies
Hinged jaws
Figure 14-11

14. Marine mammals Characteristics of marine mammals: Warm-blooded
Breathe air
Have hair (or fur)
Bear live young
Females have mammary glands that produce milk for their young

15. Marine mammals: Order Carnivora
All members of order Carnivora have prominent canine teeth
Includes:
Sea otters
Polar bears
Pinnipeds (flipper-footed)
Walrus
Seals
Sea lions/fur seals
California sea lions
Figure 14-17c

16. Differences between seals and sea lions/fur seals
Lack ear flaps
Have small front flippers
Have claws
Cannot rotate hind flippers beneath themselves
Figure 14-18

17. Marine mammals: Order Sirenia
Sirenian characteristics:
Large body size
Sparse hair all over body
Vegetarians
Toenails (on manatees only)
Includes:
Manatees
Dugongs

18. Marine mammals: Order Cetacea
Cetacean characteristics:
Blowholes on top of skull
Skull telescoped (streamlined shape)
Very few hairs
Includes:
Whales, dolphins, and porpoises

19. Marine mammals: Order Cetacea
Figure 14-20

20. Two suborders of order Cetacea
Suborder Odontoceti (toothed whales)
Echolocate (send sound through water)
Includes killer whale, sperm whale, dolphins, porpoises, and many others
Suborder Mysticeti (baleen whales)
Have rows of baleen plates instead of teeth
Includes blue whale, finback whale, humpback whale, gray whale, and many others

21. Differences between dolphins and porpoises
Dolphins have:
An elongated snout (rostrum)
A sickle-shaped (falcate) dorsal fin
Teeth that end in points
Killer whale jawbone
Figure 14-22

22. Generation of Odontoceti echolocation clicks
Figure 14-23

23. Odontoceti echolocation
Sound is bounced off objects to determine:
Size
Shape
Distance
Internal structure
Figure 14-24

24. Mysticeti: The baleen whales
Mysticeti whales have baleen instead of teeth
Baleen plates:
Hang as parallel rows from the upper jaw
Are made of keratin
Are used as a strainer to capture zooplankton
Allows baleen whales to eat krill and small fish by the ton

25. Baleen
Figure 14-25

26. Types of baleen whales Baleen whales include three families:
Gray whale (a bottom-feeder with short baleen)
Rorqual whales (medium-sized baleen)
Balaenopterids (blue whales, finback whales, and other large whales )
Megapterids (humpback whales)
Right whales (surface skimmers with long baleen)

27. An example of migration: Gray whales
Gray whales undertake the longest annual migration of any mammal:
Spend wintertime in birthing and breeding lagoons in Mexico
Spend summertime feeding in highly productive Arctic waters
Figure 14-27

28. Essentials of Oceanography 7th Edition
End of Chapter 14
Essentials of Oceanography
7th Edition