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Marine and Coastal Systems ems. 16_00CO.JPG. 16_03.JPG. “World Ocean” covers 71% of Earth’s surface. 16_02.JPG. Composition of Ocean Water. 96.5% water 3.5% salts 33-37ppt. Origin of salts? Cause of concentration variability?. Surface Currents. Currents Riverlike flows
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Marine and Coastal Systemsems 16_00CO.JPG
Composition of Ocean Water • 96.5% water • 3.5% salts • 33-37ppt • Origin of salts? • Cause of concentration • variability?
Surface Currents • Currents • Riverlike flows • Due to density differences, heating and cooling, gravity, and wind • Moderate coastal climate
Ocean Life Zones • Photic zone = well-lighted top layer, high primary productivity • Pelagic = between the ocean’s surface and floor • Benthic = ocean floor
Upwelling • Flow of deep water up toward coast to replace surface water blown away from coast • Brings nutrients to surface where light is plentiful • Productive fisheries
16_11.JPG Ocean Ecosystems
Kelp Forests • Kelp = large, dense, brown algae growing from the floor of continental shelves along temperate coasts • Shelter and food • protects shorelines from erosion • Thickeners in cosmetics, paints, paper, and soaps
Coral reef =skeletal remains of coral • Calcium carbonate • Tropical and subtropical • Protects shorelines • Most productive aquatic communities • zooxanthellae
Coral bleaching • Zooxanthellae leave coral • Climate change, pollution, natural causes? • Nutrient pollution ------algal growth------ covers coral • Divers using cyanide to capture fish • Acidification of oceans
Intertidal (littoral) ecosystems • between high tide and low tide • Tides = 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
Intertidal zones • Between high tide and low tide • Temperature, salinity, and moisture change dramatically from high to low tide
Salt marshes • Salt marsh • coasts at temperate latitude • Tides wash over sandy, silty substrates • High primary productivity • Habitat for birds and commercial fish and shellfish species • Filter pollution, slow runoff • Stabilize shorelines • Loss to development – increased flooding
Mangrove forests l • Tropical and subtropical • Mangroves = salt tolerant trees with unique roots • Curve upwards for oxygen • Curve downwards for support • Shellfish nurseries • Filter pollutants – slow runoff • Nesting areas for birds • 50% destroyed
Estuaries • where rivers flow into the ocean • Wide fluctuations in salinity and temperature as fresh water mixes with salt water from ocean • Critical habitat for shorebirds and shellfish • Transitional zone for diadromous fish • Affected by development, pollution, habitat alteration, and overfishing • Connecticut
Threats to Ocean Ecosystems • Pollution • Inadequately treated wastewater • Oil, plastic, chemicals, excess nutrients from runoff • Raw sewage and trash from cruise ships • Abandoned fishing gear • Top 10 types of debris? • A Rising Tide of Ocean Debris • Unsustainable Harvesting
16_18b.JPG • The U.S. Oil Pollution Act of 1990 • Creates a $1 billion prevention and cleanup fund • Requires all ships have double hulls by 2015
Modern fishing fleets deplete marine life rapidly • Grand Banks cod (groundfish) have been fished for centuries • Catches more than doubled with immense industrial trawlers • Record-high catches lasted only 10 years
Consumer choices influence fishing practices • Buy ecolabeled seafood • Dolphin-safe tuna • Consumers don’t know how their seafood was caught
We can protect areas in the ocean • Marine Protected Areas (MPAs) “any area of the marine environment that has been reserved by federal, state, tribal, territorial, or local laws or regulations to provide lasting protection for part or all of the natural and cultural resources therein.” (May 2000) • Marine reserves = areas where fishing is prohibited • Only 1% of MPAS • Leave ecosystems intact, without human interference • Improve fisheries, because young fish will disperse into surrounding areas
Marine Reserves • Found that reserves do work as win-win solutions • Overall benefits included… • Boosting fish biomass • Boosting total catch • Increasing fish size • Benefits inside reserve boundaries included… • Rapid and long-term increases in marine organisms • Decrease mortality and habitat destruction • Lessen the likelihood of extirpation of species
Areas outside reserves also benefit • Benefits included… • A “spillover effect” when individuals of protected species spread outside reserves • Larvae of species protected within reserves “seed the seas” outside reserves • Improved fishing and ecotourism
20-50% of the ocean should be protected in no-take reserves • Red arrows – dispersal rates of different species • Why mightMedium sized reserve be best compromise?