UNIT 3 – PELAGIC ZONE
Phytoplankton
 Pelagic environment is the largest marine ecosystem. More food, oxygen
and biota (life) are here than anywhere else.
 The dominant organism in the neritic zone and oceanic zone is ___________
 _______________ are organisms that cannot make a forward motion against
a current.
 There are two types of plankton: ________________________________
 Phytoplankton are _______________________________________________
_______________________________________________________________
 Produce __________ of all atmospheric oxygen, and are critical biomass.
They are adapted to a floating lifestyle because of their:
1. Small size - diffusion is quick, frictional drag from large surface area to low
volume ratio helps slow sinking.
2. Structure - disks shaped or chains aid in floating.
3. Low density - light ions and lipid by-products of photosynthesis reduce
density and aid floating.
 They are grouped by ______________. Different pigments allow them to
take advantage of different light penetration at various depths.
 Phytoplankton are found in 3 kingdoms and 5 phyla.
 Commercially, algae are used as ____________________ to give a smooth
texture to puddings, toothpaste, ice cream, and shoe polish.
 A “bloom” is an increase in population density of phytoplankton associated
with _____________________. It can be the result of upwelling or excessive
nutrients.
 Upwelling is caused ______________________________________________
_______________________________________________________________
_______________________________________________________________
 _______________________________________________________________
 Blooms are good for the food chain, fishing, and _______________________
 Blooms of some plankton, especially in warm water, may be harmful. When
storms follow hot, dry weather, dominant cysts of toxic phytoplankton may
be released.
 As these toxic blooms enter the food chain, they give off chemical
neurotoxins that paralyze the predator’s nerves controlling breathing and
heart rate.
 Human consumption of these organisms result in ______________________
____________________________________ due to biomagnification.
 The dominant phytoplankton in warm water are ______________________.
They cause a condition called red tide.
 Red tides is a result of a wind pattern, Peruvian fishermen named “El Nino”.
The name refers to the Christ Child, because the condition was first observed
during the warm, Christmas months of the Southern Hemisphere.
 _______________________________________________________________
_______________________________________________________________
Zooplankton
 Zooplankton are _________________________________________________
_______________________________________________________________
 They are the smallest and most numerous marine animals.
 Their population density depends on ________________________________
______________________________________________________________
 There are two groups of zooplankton:
1. Meroplankton
- planktonic larvae who will become _____________________________
__________________________________________________________
- The advantage of meroplankton lifestyle is reduced competition from
adults for the same basic needs.
- Predation is extremely high because of their size and lack of
adaptability.
2. Holoplankton
- __________________________________________________________
- Remain visible, but tiny
 Copepods (phylum: Arthropoda) are 95% of all zooplankton. Others are krill,
foraminifera and members of the Kingdom Protista, Phylum Protozoa
 Zooplankton are grouped by the way they move.
1. By ___________________________________________
2. By ___________________________________________
3. By ___________________________________________
Vertical Migration
 Vertical migration is a daily pattern of phytoplankton and zooplankton
changing positions like a day and night shift.
 During the day –
- phytoplankton produce _______________________________________
- Because oils are less dense than water, the products of photosynthesis
increase their _____________________.
 As the sun goes down –
- The phytoplankton __________________________________________
__________________________________________________________
- In response to the “rain” of phytoplankton descending, the zooplankton
move up in the water column to graze on them.
 As the sun comes up –
- Photosynthesis again causes more production than the organisms need
at that time, the phytoplankton become lighter and begin to float
upward.
- The zooplankton begin their downward response to graze again and to
take advantage of reduced visibility and less heat than at the surface.
 These two periods of grazing:
- __________________________________________________________
- __________________________________________________________
- __________________________________________________________
Taxonomy
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Taxonomy is a system of grouping organisms based on
Phylogeny (evolutionary relationships)
Biochemistry
Morphology (structure)
There are 7 taxa:
1. Kingdom: the 5 kingdoms are:
- ______________________
- ______________________
- ______________________
- ______________________
- ______________________
2. Phylum: major marine phyla from kingdom Animalia:
- Porifera
- Cnidaria
- Annelida
- Mollusca
- Arthtropoda
- Echinodermata
- Chordata
3. Class: major marine classes
from Phylum Mollusca:
- ___________________
- ___________________
- ___________________
From Phylum Arthropoda:
- ___________________
From Phylum Chordata:
- Chondrichtyes
- Osteichthyes
- Amphibia
- Reptilia
- Aves
- Mammalia
4. Order:
- Subgroups of a class
- for birds and fish the suffix is “formes”
5. Family:
- subgroups of an order;
- suffix is “ae”
Ex: ________________________
6. Genus:
- subgroups of families
- first part of scientific name
- always capitalized
Ex: Homo
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7. Species:
- __________________________________________________________
- second part of the scientific name
- always in lower case
Ex: sapiens
Carrolus Linneaus developed a system of naming organisms based on visible
characteristics.
The use of terms (genus & species) is called binomial nomenclature or the
scientific name.
A ___________________________ is used to identify the names of
unfamiliar organisms. The key is based on two choices for each pair or
related characteristics.
Scientists use a revised system based on biochemistry to name all the
discovered organisms.
Only about 1 million of nearly 10 million organisms have been identified and
named so far.
Order Cetacea - Whales, Dolphins, Porpoises
Phylum Chordata; Class Mammalia
Cetaceans are grouped on the basis of their mouths:
a. Mysticeti
- __________________________________________________________
- Both nostrils have a blow hole
b. Ordontoceti
- __________________________________________________________
- Carnivores
- 2 nostrils but only 1 blow hole
- Smaller in size
Marine Mammal Characteristics:
1. __________________________________________________
2. __________________________________________________
3. __________________________________________________
4. __________________________________________________
5. __________________________________________________
6. __________________________________________________
Blue whale
- ________________________________________
- 100 ft. long
- 150 tons.
Narwhal
- ________________________________________
- left tooth found only in males.
Beluga whales
- pure white as adults
- “sea canaries”
Dolphins
- are the most social 7 intelligent whale.
- Body temperature of 97.7o F
- 7 minutes between breaths
- 25 mph swimming speed
- River dolphins of S. America cannot swim in a straight line
Marine Mammals Protection Act of 1972
 Whales and all marine mammals are protected
 Passed in response to ____________________ killing of dolphins in huge
4,000 ft long nets.
 Many are still being hunted to extinction under the guise of scientific
research or are by-catch of the tuna fishery.
 1 million deaths/year
 Tuna caught on lines is “certified” as dolphin safe by company employees
 International Whaling Commission (I.W.C.) is a whaler’s organization that
sets quotes based on catch size. They are not a regulatory agency and
compliance is voluntary.
Cetacean Adaptations:
Swimming:
- powerful tail flukes
- __________________________________________________________
- Sei whales are fastest (40mph)
Digestion
- Multi-compartmentalized stomachs “chew” food
- Teeth are conical and unspecialized
- Baleen whales
o feed by swimming through pockets of plankton
o ______________________________________________________
o Stomachs hold 2 tons of krill
- Toothed whales hunt in packs and seek out individual fish, penguins,
seals, sharks or other whales.
Circulation
- high blood volume holds maximum oxygen and glucose levels
- Large whales have large veins
- Blood can be shunted to brain, heart, lungs, and muscles and away
from stomach and kidneys to protect vital organs.
- A 4-chambered heart can transfer arteriole heat to the _____________
__________________________________________________________
- ___________________ insulates against the cold.
- Overheating is solved by _____________________________________
__________________________________________________________.
- Whales in captivity exercise less and often lose the ability to cool off by
straightening the fins.
Senses
- Vision is poor
- Vocalizations & echo-location compensate
- Whales have no vocal cords but make songs, clicks and shines by
vibrations in the _________________________.
- Communicate to:
o __________________________________
o __________________________________
o __________________________________
- Families of whales have their own dialect
- Sounds are emitted and amplified in the head through an oil filled
cavity called a ______________.
- __________________________________________________________
__________________________________________________________
- The sounds are extremely accurate and VERY LOUD
- Can be used to stun prey
- Blue whale can make a sound of 188 decibels. (can rupture a human
eardrum)
- When whales enter the thermocline, sounds can be heard 1/4 of the
distance around the earth.
Diving:
- lungs are completely filled and emptied quickly through the blow hole
on the top of the head.
- A trachea under the blow hole connects directly to _____________.
- Cannot breathe through their mouth.
- The nasal passage closes when relaxed to prevent water from entering
the lungs & allows them to sleep for short periods without drowning.
- __________________________________________________________
- Some whales go to depths of 13,000 ft and breathe every 90 minutes
- __________________________________________________________
- __________________________________________________________
Excretory:
- Specialized kidneys allow whales to drink salt water.
- The urine is very saline
Reproduction
- mating usually occurs in _____________________________
- Implantation of the egg may be delayed several months, so that
gestation finishes up in the warm summer months.
- Many whales only have one calf every ___________________.
- Babies weigh _____________________