CHAPTER 14 Animals of the Pelagic Environment

How organisms avoid sinking  Increase buoyancy Gas containers ○ Rigid container such as shells (internal or external) or… ○ Swim bladder Fig

How organisms avoid sinking  Float – less dense than saltwater or neutral Microscopic zooplankton have shells or tests ○ Radiolarians ○ Foraminifers ○ Copepods Macroscopic zooplankton may have oil droplets Krill (resemble mini-shrimp or large copepods) Fish egg with oil droplet /MicroGalleryLarge_files/Forams1.jpg Foraminifers Krill

How to avoid sinking  Floating macroscopic zooplankton  Cnidarians Hydrozoan (Portuguese man-of-war) gas-filled float Scyphozoan (jellyfish) soft low-density bodies

How to avoid sinking Fig Active swimming Fish – swim by curving body from front to back es/anims/thumbnails/266_sm.gif

How to avoid sinking Active swimming – Squid Swim by trapping water and expelling it Also swim by using fins Unknown deep sea squid

How to avoid sinking Active swimming sea turtles use flippers marine mammals use up/down tail movements Different from fish Sperm whale

Fin designs in fish  Vertical fins as stabilizers ○ dosral and anal fins  Paired fins for “steering” and balance ○ Pelvic and pectoral  Tail fin (caudal) for thrust

Fin designs in fish  Rounded caudal fins  Rounded caudal fins flexible, maneuver at slow speeds  Truncate finsforked fins  Truncate fins and forked fins, useful for both maneuvering and thrust  Lunate fins  Lunate fins rigid, lots of thrust for fast swimmers  Heterocercal fins  Heterocercal fins asymmetrical, lift for buoyancy (shark)

Adaptations for finding prey  Mobility  Lungers  Lungers wait for prey and pounce (grouper) Mainly white muscle tissue  Cruisers  Cruisers actively seek prey (tuna) Mostly red muscle tissue

Adaptations for finding prey  Swimming speed Speed generally proportional to size Can move very fast for short time (mainly to avoid predation)

Adaptations to finding prey  Most fish cold-blooded but some are warm- blooded Homeothermic-body temperature above sea water temperature Modifications in circulatory system Mainly in fast-swimming fish

Adaptations of deep-water nekton  Mainly fish that consume detritus or each other  Lack of abundant food  Bioluminescence ○ n_underwater_world.html n_underwater_world.html  Fishing lures  Large, sensitive eyes Lanternfish Anglerfish w/ males

Adaptations of deep-water nekton  Large sharp teeth  Expandable bodies  Hinged jaws Gulper eel

Figure 14.12

Adaptations to avoid predation  Schooling “Safety in numbers” School may appear as single larger unit Schooling maneuvers confuse predator

Some taxonomy……  Fish Kingdom Animalia ○ Phylum Chordata Class Chondrichtyes – cartilaginous fish - Sharks, rays Class Osteichthyes – bony fish

Marine Mammals  Kingdom Animalia Phylum Chordata ○ Class Mammalia Order Carnivora - Sea otters - Polar Bears - Pinnipeds – Family Odobenidae (walrus), Family Otariidae (Sea lions), Family Phocidae (seals) Order Sirenia - Manatees and dugongs Order Cetacea - Whales

 Whales  Kingdom Animalia Phylum Chordata ○ Class Mammalia Order Cetacea - Suborder Odontoceti (toothed whales – dolphins, orcas, sperm whales) - Suborder Mysticeti (baleen whales – blue whale, gray whale)

Marine mammals  Land-dwelling ancestors  Warm-blooded  Breathe air  Hair/fur  Bear live young  Mammary glands for milk

Marine mammals  Carnivora Prominent canine teeth Sea otters Sea otters Polar bears Polar bears pup-_T9J9119-Cordova,-AK.jpg

Marine mammals  Carnivora Pinnepeds Pinnepeds ○ Walruses Eat crustaceans with tusks ○ Seals

Marine mammals  Carnivora Pinnepeds Pinnepeds ○ Sea lions ○ Fur seals

Marine mammals  Sirenia  Herbivores Manatees Manatees ○ Coastal areas of tropical Atlantic Ocean Dugongs Dugongs ○ Coastal areas of Indian and western Pacific Oceans

Marine mammals  Cetacea  Stream-lined bodies for fast swimming  Specialized skin (dermal ridges) structure for fast swimming  Whales Toothed - carnivores Baleen – filter feeders

Cetacea Fig

Marine mammals Dolphins vs. porpoises Dolphins (Delphinidae) ○ 35 species ○ Beaks ○ melon (fatty organ in forehead) ○ Prominent, curved dorsal fin ○ conical, undifferentiated teeth ○ Range in size from 1.5 m Hector's dolphin to 9 m killer whales Porpoises (Phocoenidae) ○ 6 species ○ Lack prominent beak ○ laterally compressed teeth ○ More triangular dorsal fin education/images/harbourporpoise/teeth2_small.gif Harbor porpoise Bottlenose dolphin

Cetacea  Adaptations for deep diving Use oxygen efficiently ○ Able to absorb 90% of oxygen inhaled ○ Able to store large quantities of oxygen – high levels of myoglobin and hemoglobin ○ Able to reduce oxygen required for noncritical organs ○ Slowed cardiac rate Muscles insensitive to buildup of CO 2 Collapsible lungs

Adaptations for deep diving Sperm whales can dive up to 1 hour, 52 min. and to 3 km deep

Cetacea Odontoceti  Suborder Odontoceti (toothed) Dolphins, porpoises, killer whale, sperm whale Echolocation to determine distance and direction to objects ○ Clicks produced in nasal air sacs are focused by the melon ○ Echos received thru lower jaw  middle ear Determine shape, size of objects

Intelligence in toothed whales  Large brains relative to body size  Communicate with each other  Brains convoluted  Trainable  Are they intelligent?

Cetacea  Baleen whales  Blue whale, finback whale, humpback whale, gray whale, right whale baleen  Fibrous plates of baleen sieve prey items  Vocalized sounds for various purposes Suborder Mysticeti Fig Right whale feeding Right whale baleen

Gray whale migration 22,000 km (13,700 mi) annual migration from coastal Arctic Ocean to Baja California and Mexico Feeding grounds in Arctic (summer) Breeding and birthing grounds in tropical eastern Pacific (winter) Fig

Whales as endangered species  Fewer whales now than before whaling  International Whaling Treaty  Hunting of gray whale banned in 1938  Gray removed from endangered list in 1993 as population rebounded Fig

Marine reptiles ○ Sea turtles Prey depends on species Greens Greens eat seagrass (gut flora digests cellulose) Loggerheads Loggerheads eat conch Leatherbacks Leatherbacks eat jellyfish Nest on beaches: predation, lights on dunes Many overexploited Leatherback Green Loggerhead

○ Marine iguanas ○ Marine iguanas of Galapagos Islands Feed on submerged algae Dive for up to 20 minutes Must surface before they become too cold and can’t climb out of water l%20zoo/they%20walk/iguana rogram_pics/photogallery/gps

○ Sea snakes ○ Sea snakes of Pacific Highly poisonous Truly aquatic - reproduce in water - live-bearers

Misconceptions

Florida Sunshine State Standards

Ocean Literacy Principles  3e. - The ocean dominates the Earth’s carbon cycle. Half the primary productivity on Earth takes place in the sunlit layers of the ocean and the ocean absorbs roughly half of all carbon dioxide added to the atmosphere.  5a. - Ocean life ranges in size from the smallest virus to the largest animal that has lived on Earth, the blue whale.  5b. - Most life in the ocean exists as microbes. Microbes are the most important primary producers in the ocean. Not only are they the most abundant life form in the ocean, they have extremely fast growth rates and life cycles.  5c. - Some major groups are found exclusively in the ocean. The diversity of major groups of organisms is much greater in the ocean than on land.  5d. - Ocean biology provides many unique examples of life cycles, adaptations and important relationships among organisms (symbiosis, predator-prey dynamics and energy transfer) that do not occur on land.  5e. - The ocean is three-dimensional, offering vast living space and diverse habitats from the surface through the water column to the seafloor. Most of the living space on Earth is in the ocean.  5f. - Ocean habitats are defined by environmental factors. Due to interactions of abiotic factors such as salinity, temperature, oxygen, pH, light, nutrients, pressure, substrate and circulation, ocean life is not evenly distributed temporally or spatially, i.e., it is “patchy”. Some regions of the ocean support more diverse and abundant life than anywhere on Earth, while much of the ocean is considered a desert.  5g. - There are deep ocean ecosystems that are independent of energy from sunlight and photosynthetic organisms. Hydrothermal vents, submarine hot springs, methane cold seeps, and whale falls rely only on chemical energy and chemosynthetic organisms to support life.  5h. - Tides, waves and predation cause vertical zonation patterns along the shore, influencing the distribution and diversity of organisms.  5i. - Estuaries provide important and productive nursery areas for many marine and aquatic species.