Marine Ecosystems

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Marine Ecosystems
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Marine Wildlife Habitat(birds, mammals, reptiles)

• aquatic feeding environment
• breeding environment (can be terrestrial)

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Marine Wildlife Habitat

• neritic watersthese are waters that lie over the
  continental shelf the outer limit of the neritic
  waters roughly corresponds with the 200 meter
  depth contour. This tends to be the richest area
  for feeding.

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Marine Wildlife Habitat

• oceanic watersthese are deep waters that are
  seaward of the continental shelf break.

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Ocean currents and wind patterns
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upwellings
upwellings
Ocean currents and wind patterns
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Marine Wildlife Habitat

• Marine wildlife distribution
• reflects feeding areas, can be further refined
  into the inshore (I), offshore (O), and pelagic
  (P) zones

Zones
I
O
P
Continental shelf
Continental land mass
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Marine Wildlife Habitat

• Marine wildlife distribution

Inshore zone (I)- from high water mark to about
4-5 miles out to sea.
Zones
I
O
P
Continental shelf
Continental land mass
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Marine Wildlife Habitat

• Marine wildlife distribution

Offshore zone (O)- the region from the outer
edge of the inshore zone to the continental
shelf edge.
Zones
I
O
P
Continental shelf
Continental land mass
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Marine Wildlife Habitat

• Marine wildlife distribution

Pelagic zone (P)- comprises the entire deep ocean
outside the shelf areas (oceanic waters).
Zones
I
O
P
Continental shelf
Continental land mass
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Breeding Habitat

• Marine birds often nest in colonies on islands,
  cliffs

Laysan albatross, Midway Island
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Breeding Habitat

• Sea turtles return to natal beach to lay eggs in
  sand, either alone or in arribadas

Olive ridley turtles in Costa Rica
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Breeding Habitat

• Whales may migrate from feeding to breeding
  grounds every year

Grey whale migration route
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Aquatic and Marine Adaptations

• Mammals
• 1. Structural adaptations
• a. fusiform body shape
• b. thick blubber layer
• c. flippers, fins, or webbed feet
• d. some with valves in nose

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Aquatic and marine adaptations

• 2. Physiological adaptations
• a. active in apnea (high O2 concentration in
  blood)
• b. rapid gas exchange
• c. red blood cells, myoglobin
• d. drop in heart rate during dives

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Aquatic and marine adaptations

• Birds
• 1. Structural adaptations
• a. fusiform body shape
• b. thick fat layer
• c. dense feathers
• d. webbed feet
• e. protective eyelids

Note shape
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Aquatic and marine adaptations

• 2. Physiological adaptations
• a. air sac system
• b. rapid gas exchange
• c. red blood cells, myoglobin
• d. drop in heart rate during dives

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The Bering Sea Ecosystem
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Bering Sea Ecosystem

• One of worlds richest marine areas
• Large numbers of seabirds and marine mammals
  (whales, pinnipeds,walrus)
• One of worlds largest fisheries-walleye pollock
  (a bottom fish)
• Not harvested until about 1970

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Bering Sea Ecosystem

• Used for imitation crab other products
• Early 1990s-catch plummeted
• Large by-catch of other fish were correlated with
  declines in some marine mammals and birds
• Major species impacted-Stellers sea lion and
  Alaska fur seal.

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Bering Sea Ecosystem

• Stellers sea lion population has crashed
• Poor pup survival
• No evidence of unusual pathogens
• No problems with toxic chemicals
• Pups die of starvation
• Points to food chain problems
• Overfishing??

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Bering Sea Ecosystem

• Commercial harvest of fur seals limited since
  1911
• Alaska fur seal population declined by half
  during 70s
• Harvest ceased in 1983 after declines
• Parental feeding normal, animals healthy
• Possible net mortality of 30,000/year

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Drift Gill-net fisheries

• Gill-net fishery important in various parts of N.
  America and other parts of the world.
• Major problem is incidental take
• Seabirds, sea turtles, dolphins
• 100,000s of animals killed each year world-wide

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Green Sea Turtle
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Estuary Ecosystems

• Partially sheltered areas where rivers discharge
  into ocean
• Fresh to saltwater salinity gradient
• Highly productive ecosystems
• Salt marsh in temperate zone, mangroves in tropics

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Salt marsh
Spartina patens
Spartina alterniflora
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Mangrove estuary