AP Environmental Science Mr. Grant Lesson 80

© 2011 Pearson Education, Inc.

AP Environmental Science

Mr. GrantLesson 80

Marine and Coastal Ecosystems

&

Marine Pollution


Objectives:

• Define the term by-catch.• Describe major types of marine ecosystems.• Assess impacts from marine pollution.


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"

Define the term by-catch.


Describe major types of marine ecosystems.

• Major types of marine and coastal ecosystems include pelagic and deep-water open ocean systems, kelp forests, coral reefs, intertidal zones, salt marshes, mangrove forests, and estuaries.

• Many of these systems are highly productive and rich in biodiversity. Many also suffer from human influence.


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

• 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


Open ocean systems vary in biodiversity• Microscopic phytoplankton are the base of the marine

food chain- Algae, protists, cyanobacteria- They feed zooplankton- Which then feed fish, jellyfish, whales, etc.

• Predators at higher trophic levels - Larger fish, sea turtles,

sharks, and fish-eating birds


Animals of the deep ocean

• Animals adapt to extreme water pressure and the dark- Scavenge carcasses or organic detritus- Predators- Others have mutualistic relationships with bacteria- Some carry bacteria that produce light chemically by

bioluminescence• Hydrothermal vents support

tubeworms, shrimp, and other chemosynthetic species


Kelp forests harbor many organisms

• Kelp = large, dense, brown algae growing from the floor of continental shelves

• 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 it in food, cosmetics, paints, paper, soap, etc.


Coral reefs are treasure troves of biodiversity• Coral reef = a mass of calcium carbonate composed of

the skeletons of tiny marine animals (corals)- They 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 = tiny colonial invertebrate animals- Related to sea anemones and jellyfish- Attach to a rock or reef and capture passing food with

stinging tentacles- Get food from symbiotic algae (zooxanthallae)


Most corals are colonial

• Reefs consist of millions of densely packed animals• Reefs are located in shallow subtropical and tropical

waters- Protect shorelines by absorbing waves- Innumerable invertebrates and fish species find food

and shelter in reef nooks and crannies


Coral reefs are in worldwide decline• “Coral bleaching” = occurs when zooxanthellae leave

the coral or die- Corals lose their color and die, leaving white patches- 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


Deepwater coral reefs exist

• They thrive in waters outside the tropics - On ocean floor at depths of 200–500 m (650–1,650 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


Intertidal zones undergo constant change

• Intertidal (littoral) 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• Intertidal organisms spend part of their time submerged

in water and part of their time exposed to sun and wind


A typical intertidal zone


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

• Sandy intertidal zones have slightly less biodiversity


Salt marshes line temperate shorelines• Salt marshes = occur along coasts at temperate latitudes

- Tides wash over gently sloping sandy, silty substrates• Tidal creeks = channels that rising and falling tides flow

into and out of• Salt marshes have very high primary productivity

- Critical habitat for birds, commercial fish, and shellfish

- They filter pollution- They stabilize shorelines against storm surges


People change and destroy salt marshes

• People want to live or do business along coasts- We lose key ecosystem services- Flooding (e.g., from Hurricane Katrina) worsens


Mangrove forests line coasts

• In tropical and subtropical latitudes - They replace salt marshes along sandy coasts

• Mangroves = salt-tolerant trees - Their unique roots curve up for oxygen and down for

support• Nesting areas for birds• Nurseries for fish and shellfish

Mangroves provide food, medicine, tools, and construction materials


Mangrove forests have been destroyed• Half the world’s mangrove forests are gone

- Developed for residential, commercial, and recreational uses

- Shrimp farming• Once destroyed, coastal areas no longer:

- Slow runoff- Filter pollutants- Retain soil- Protect communities against storm surges


Fresh and salt water meet 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


Assess impacts from marine pollution.

• People pollute ocean waters with trash, including nets and plastic that harm marine life.

• Plastic trash accumulate in ocean regions where it is trapped by currents.

• Marine oil pollution results from non-point sources on land as well as from spills at sea from tankers and drilling platforms.

• Heavy metal contaminants in seafood affect human health.

• Nutrient pollution can lead to dead zones and harmful algal blooms.


Marine pollution

• People use oceans as a sink for waste and pollutants• Even into the mid-20th century, coastal U.S. cities

dumped trash and untreated sewage along their shores• Nonpoint source pollution comes from all over

- Oil, plastic, chemicals, excess nutrients

In 2008, 391,000 Ocean Conservancy volunteers from 104 nations picked up 3.1 million kg (6.8 million lb) of

trash from 27,000 km (17,000 miles) of shoreline


Nets and plastic debris endanger life

• Plastic items dumped into the sea harm or kill wildlife- Wildlife mistake it for food- 98% of dead northern

fulmars had plastic in their stomachs

• Plastic is nonbiodegradable- Drifts for decades- Breaks into tiny pieces

Trillions of tiny plastic pellets float in the oceans and are eaten


Plastic trash is accumulating in the oceans

• Circulating currents bring and trap plastic trash to areas- The northern Pacific Gyre stretches from California to

Hawaii to Japan- This “Great Pacific Garbage Patch” is the size of Texas

and has 3.3 plastic bits/m2

• The 2006 Marine Debris Research, Prevention, and Reduction Act is not enough

• We must reduce, reuse, and recycle more plastic- Participate in efforts such as the International Coastal

Cleanup


Oil pollution comes from spills of all sizes

• 30% of oil and 50% of natural gas come from seafloor deposits- North Sea, Gulf of Mexico

• Drilling in other places is banned- Spills could harm valuable

fisheries• The Deepwater Horizon

exploded off Louisiana’s coast in April 2010- Spilling 140 gallons/min- Hitting coasts of four states


Oil spills have severe consequences

• Major spills make headlines- Foul beaches- Coat and kill animals- Devastate fisheries

• Countless non-point sources produce most oil pollution- Small boat leaks, runoff

Major oil spills cause severe environmental and economic problems


Oil spills have decreased

• Due to emphasis on spill prevention and response- Stricter regulations are

resisted by the oil industry• The U.S. Oil Pollution Act

(1990)- Created a $1 billion

prevention and cleanup fund - Requires that all ships have

double hulls by 2015 Recently, oil spills have decreased


Toxic pollutants contaminate seafood

• Toxic pollutants can make food unsafe to eat• Mercury contamination from coal combustion and other

sources bioaccumulates and biomagnifies- Dangerous to children and pregnant or nursing women

• Avoid eating swordfish, shark, and albacore tuna- Eat seafood low in mercury (catfish, salmon, canned

light tuna)• Avoid seafood from areas where health advisories have

been issued


Excess nutrients cause algal blooms

• Harmful algal blooms = nutrients increase algae that produce powerful toxins

• Red tide = algae that produce red pigments that discolor water- Illness and death to wildlife

and humans- Economic loss to fishing

industries and beach tourism• Reduce runoff • Do not eat affected organisms

Documents

AP Environmental Science Mr. Grant Lesson 80