Download APES Lesson 77 (5th Ed) - Marine and Coastal Ecosystems

AP Environmental
Science
Mr. Grant
Lesson 77
Marine and Coastal
Ecosystems
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Mastery Check
Where in the oceans are productive areas of
biological activity likely to be found?
Biologically productive areas are concentrated in areas of
upwelling, in the shallower waters along continental margins, and
at hydrothermal vents of the deep mid-ocean ridges.
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Objectives:
• Define the term by-catch.
• Describe major types of marine ecosystems.
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Define the term by-catch.
By-Catch:
Unwanted marine creatures that are caught in the
nets while fishing for another species; "thousands
of dolphins and porpoises and whales are killed
as part of the by-catch each year"
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Describe major types of marine ecosystems.
• Major types of marine and coastal ecosystems include
intertidal zones, salt marshes, mangrove forests,
estuaries, kelp forests, coral reefs, pelagic and deepwater open ocean systems.
• Many of these systems are highly productive and rich in
biodiversity. Many also suffer heavy impacts from
human influence.
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Marine and Coastal Ecosystems
 Regions of ocean water differ greatly
 Some zones support more life than others
 Photic zone = well-lighted top layer
 Absorbs 80% of solar energy
 Supports high primary productivity
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Marine and Coastal Ecosystems
 Pelagic = habitats and ecosystems between the
ocean’s surface and floor
 Benthic = habitats and ecosystems on the ocean
floor
 Most ecosystems are powered by solar energy
 But even the darkest depths host life
 Marine systems are interconnected with freshwater
ones
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Marine and coastal ecosystems
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Intertidal zones undergo constant change
 Intertidal (littoral) ecosystems = ecosystems
where the ocean meets the land
 Between the uppermost reach of the high tide and the
lowest limit of the low tide
 Tides = periodic rising and falling of the ocean’s
height due to the gravitational pull of the sun and
moon
 High and low tides occur roughly 6 hours apart
 Intertidal organisms spend part of their time
submerged in water and part of their time exposed
to sun and wind
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Intertidal zones undergo constant change
 Intertidal zones are a tough place to live, but they
have amazing diversity
 Rocky shorelines, crevices, pools of water (tide pools)
 Anemones, mussels, barnacles, urchins, sea slugs,
starfish, and crabs
 Temperature, salinity, and moisture change
dramatically from high to low tide
 Environmental variation creates horizontal bands of
habitat
 Sandy intertidal zones have slightly less biodiversity
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Intertidal zones undergo constant change
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A typical intertidal zone
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Intertidal
zones are a
tough place
to live
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Salt marshes line temperate shorelines
 Salt marshes = occur along coasts at temperate latitudes
 Tides wash over gently sloping sandy, silty substrates
 Rising and falling tides flow into and out of channels
called tidal creeks and overflow onto marsh flats
 Salt marshes have very high primary productivity
 Thick with salt-tolerant grasses, sedges, shrubs
 Critical habitat for birds, commercial fish, and shellfish
 They filter pollution
 They stabilize shorelines against storm surges
 Many have been lost because people want to live or do
business along coasts
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Salt marshes line temperate shorelines
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People change and destroy salt marshes
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Mangrove forests line coasts in the tropics and
subtropics
 In tropical and subtropical latitudes mangrove
forests replace salt marshes along sandy coasts
 Mangroves = salt-tolerant trees that can live in
changing water levels
 Their unique roots curve up for oxygen and down for
support
 Provide nesting areas for birds, nurseries for fish
and shellfish, food, medicine, tools, and construction
materials
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Mangrove forests line coasts
Mangroves provide food,
medicine, tools, and construction
materials
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Mangrove forests line coasts in the tropics and
subtropics
 Half the world’s mangrove forests are gone
 Developed for residential, commercial, and
recreational uses
 Removed for shrimp farming
 Once destroyed, coastal areas no longer:
 Slow runoff
 Filter pollutants
 Retain soil
 Protect communities against storm surges
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Mangrove forests have been destroyed
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Fresh meets salt water in estuaries
 Estuaries = water bodies where rivers flow into the
ocean, mixing fresh and salt water
 They are biologically productive
 Have fluctuations in salinity
 Critical habitat for shorebirds and shellfish
 Transitional zone for fish that spawn in streams and
mature in salt water
 They have been affected by development, pollution,
habitat alteration, and overfishing
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Fresh and salt water meet in estuaries
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Kelp forests harbor many organisms
 Kelp = large, dense, brown algae growing from the
floor of continental shelves
 Can reach 60 m (200 ft) long and grow 45 cm (18 in)
per day
 Dense strands form kelp forests along temperate
coasts
 They provide shelter and food for organisms
 They absorb wave energy and protect shorelines from
erosion
 People use kelp in food, cosmetics, paints, paper,
soap, etc.
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Kelp forests harbor many organisms
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Coral reefs are treasure troves of biodiversity
 Coral reef = a mass of calcium carbonate
composed of the skeletons of tiny marine animals
(corals)
 May be an extension of a shoreline
 Or exist along a barrier island, parallel to the shore
 Or as an atoll (a ring around a submerged island)
 Corals are tiny colonial invertebrate animals related
to sea anemones and jellyfish
 Attach to a rock or reef and capture passing food with
stinging tentacles
 Get nourishment from symbiotic algae (zooxanthallae)
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Coral reefs are treasure troves of biodiversity
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Coral reefs are treasure troves of biodiversity
 Reefs consist of millions of densely packed animals
 Colors come from zooxanthellae
 Reefs are located in shallow subtropical and tropical
waters
 Protect shorelines by absorbing waves
 Reefs provide complex physical structure
 High primary productivity
 Innumerable invertebrates and fish species find food
and shelter in reef nooks and crannies
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Most corals are colonial
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Coral reefs are treasure troves of biodiversity
 Coral bleaching occurs when zooxanthellae leave
the coral or die
 Corals lose their color and die, leaving white patches
 Results from climate change, pollution, or unknown
natural causes
 Nutrient pollution causes algal growth, which
smothers coral
 Divers damage reefs by using cyanide to capture
fish
 Acidification of oceans deprives corals of carbonate
ions for their structural parts
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Coral reefs are in worldwide decline
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Coral reefs are treasure troves of biodiversity
 A few coral species thrive in waters outside the
tropics
 On the ocean floor at depths of 200–500 meters
(650–1650 ft)
 Occur in cold-water areas off the coasts of Spain, the
British Isles, and elsewhere
 Little is known about these reefs
 Already, many have been badly damaged by trawling
 Some reefs are now being protected
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Deepwater coral reefs exist
Squat lobsters on a cold-water coral
reef off the coast of Ireland
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Open-ocean ecosystems vary in their
biodiversity
 Microscopic phytoplankton are the base of the
marine food chain
 Productivity is concentrated in areas of nutrient-rich
upwelling
 Algae, protists, cyanobacteria feed zooplankton,
which then feed fish, jellyfish, whales, etc.
 Predators at higher trophic levels
 Larger fish, sea turtles, sharks, and fish-eating birds
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Open ocean systems vary in biodiversity
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Open-ocean ecosystems vary in their
biodiversity
 Animals of the deep ocean have adapted to extreme
water pressure and the dark
 Some scavenge carcasses or organic detritus
 Others are predators
 Others have mutualistic relationships with bacteria
 Hydrothermal vents support tubeworms, shrimp, and
chemosynthetic bacterial species
 Derive energy from chemicals in the heated water
rather than photosynthesis
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Animals of the deep ocean
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