Estuaries

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Estuaries

• Where freshwater and saltwater meet
• Water levels in estuaries rise and fall with the
  tides.
• Salinity fluctuates with
• Tidal cycles
• Time of year
• Precipitation

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Estuaries

• Organisms must tolerate wide fluctuations in
  salinity, temperature and light.
• Among the most fertile, productive systems in the
  world.
• Nutrients from land and upstream
• Tidal action stirs up the nutrients and removes
  wastes
• Shallow water, so high light penetration
• Presence of many plants

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Oceans

• Covers 71 of the Earths surface
• Oceans contain 96.5 water with the salinity
  being in the range of 33 - 37 ppm. Varies place
  to place due to evaporation , precipitation and
  freshwater sources.
• Ions found Cl- 1.9, Na 1.1, SO42- 0.3, Mg2
  0.1, Ca2 0.04, K 0.04 and HCO3- 0.01

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Oceans

• Salinity near the equator is low due to high
  precipitation
• Salinity 30-35 degrees north and south of that is
  high due to evaporation exceeding precipitation
• Dissolved oxygen as well as phosphates and
  nitrates are also key abiotic factors.

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Oceans

• Vertical structured and horizontally flowing
• Water density increases as salinity increases and
  temperature decreases. Results in different
  layers of water.
• Water at the surface is heated by sunlight and
  stirred by the wind.

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Oceans

• Surface Zone range 0 150 m 2 of ocean water
  by volume. Heated by sunlight, stirred by wind.
• Pycnocline Zone density of water increses
  rapidly with depth 18 of ocean water volume
• Deep Zone Sluggish and unaffected by winds or
  sunlight remaining 80 of ocean water volume

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Oceans

• Midlatitude ocean temperature only experiences a
  10 degree celsius annual temperature variation.
• Tropical and polar regions even more stable.
• Reason high heat capacity of water.

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Ocean

• Currents is the horizontal movement of the waters
  within 400 m of the surface.
• Caused by the density differences, heating and
  cooling, gravity and wind.
• Currents transport nutrients, heat, larvae and
  even pollution.

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Ocean

• Vertical Movement
• Upwelling caused when the colder, deeper water
  moves to the surface. Occurs where currents
  diverge or flow away from one another. Winds
  parallel or from inland can cause condition as
  well. Rich in nutrients from the bottom, great
  fishing!
• Downwelling Currents converge, surface water
  sinks. Warm water rich in DO provides influx of
  oxygen for deep water organisms.

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Topography

• Underwater mountains and valleys affect the
  biodiversity.
• Continental Shelf gentle sloped shallow waters
  bordering continents 1.9 m per km
• Photic zone upper 10 m absorbs 80 of sunlight
  and is thus where almost all the oceans primary
  productivity occurs.

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Topography

• Pelagic between photic zone and benthic zone
• In Open-Ocean ecosystems, primary productivity
  and abundant animal life occurs in pelagic zones
  if areas of updwellings.
• Benthic - ocean floor

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Marine Coastal Ecosystems

• Open-Ocean Phytoplankton is base of food chain.
  Zooplankton (photsynthetic algae, protists and
  cyanobacteria) feed fish, whales and other
  swimming animals. Higher trophic level animals
  (turtles, sharks and large fish) feed on them.

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Marine Coastal Ecosystems

• Within the continental shelf, kelp forests and
  coral reefs are unique ecosystems.
• Kelp is actually brown algae that grows from the
  floor of continental shelf towards sunlit
  surface. Faster (18 per day) than kudzu.

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Marine Coastal Ecosystems

• Kelp forests shelter and provide food for
  invertebrates and fish and thus provide a happy
  hunting ground for higher trophic level (seals,
  sharks and sea otters).
• Keystone species of sea otters feed on sea
  urchins that feed on kelp. No sea otters.

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Marine Coastal Ecosystems

• Kelp forests ecosystem service is as a wave
  energy absorber
• Kelp forests are found in high primary
  productivity areas near shoreline.

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Marine Coastal Ecosystems

• Coral Reefs are also in areas of high primary
  productivity near shore lines mostly in
  subtropical and tropical waters.
• Coral reefs are a mass of CaCO3 skeletons of tiny
  colonial marine organisms known as corals.
• Receive their nutrients from tiny, symbiotic
  algae called zooxanthelle

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Marine Coastal Ecosystems

• Zooxanthelle give the coral reefs their exquisite
  colors.
• Ecosystem service is also as a wave energy
  absorber. Look at Pacific atolls with reef
  systems.

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Marine Coastal Ecosystems

• Dangers to coral reef ecosystems cause coral
  bleaching the zooxanthenelle leave the coral.
  Lose their color or die as a result of
• Increased surface temperature due to climate
  change
• Influx of pollutants
• Or combination of both

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Marine Coastal Ecosystems

• Other threats to reefs
• Influx of nutrient pollutants (PO43- and NO31-)
  leading to algae blooms that blanket reefs
  (Florida Keys).
• Increased amounts of CO2 from the atmosphere
  increasing acidity
• Bottom-trawling fishing

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Marine Coastal Ecosystems

• Deep water reefs exist off Norway, Spain and
  British Isles. Cooler waters.
• Fishery habitat for commercial cod threatened

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Fishing

• International community studies have predicted
  total collapse of worlds marine current fished
  resources by 2048
• 50 of the worlds marine fish are fully
  exploited more intense fishing of those species
  will lead to extinction.

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The Global Fish Harvest
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Fishing

• 25 of the worlds marine fish are over exploited
  are headed towards extinction.
• We are already seeing fishery collapse off the
  coast of Newfoundland and New England

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Fisheries in Distress Cod Landings from Georges
Bank, 1982-2004
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Industrial Fishing

• Commercial fleets use fossil fuels, huge vessels
  and new technologies to capture fish in undreamed
  of numbers. Factory fishing ships even package
  and freeze fish for markets while underway.

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Commercial Fishing Damages to Ecosystems

• By-catch accidental catching of non-target
  species accounts for the deaths of thousands upon
  thousands of fish, sharks, marine mammals and
  birds.
• Dolphin deaths alone in 1986 were 133 000 a year.
  In 1998 had dropped to 2 000 a year

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Trawler fishing
Fish farming in cage
Spotter airplane
Sonar
Purse-seine fishing
Trawl flap
Trawl lines
Fish school
Trawl bag
Drift-net fishing
Long line fishing
Buoy
Float
Lines with hooks
Deep sea aquaculture cage
Fish caught by gills
Fig. 12-A, p. 255
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Commercial Fishing Methods

• Driftnetting
• Long nets , spanning large expanses that drift
  with the currents
• Capture passing fish
• Target fish that travel in large schools in open
  waters such as herring, sardines and mackeral
  (even sharks)

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Fishing

• Long-line Fishing
• Extremely long-lines extended out with baited
  hooks along the line (Perfect Storm).
• Goal is to catch larger fish like tuna, swordfish
  and halibut.

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Fishing

• Purse-Seine Fishing schools are surrounded by a
  large net. Bottom of net in cinched up and then
  gathered up.
• Target fish herring, mackerel, yellowfin tuna
  and anchovies that feed in schools along the
  surface.

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Fisheries Problems Bottom Trawling
Too many boats High technology Too few fish
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Fishing

• Trawling
• Drag immense cone shaped nets behind the boat.
  Weighted at bottom with floats attached at to to
  keep them open.
• Catch pelagic fish in open waters
• Bottom-trawling
• Continental-shelf goal is to catch ground fish,
  shellfish and other benthic organisms

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Commercial Fishing Damages to Ecosystems

• Drift netting by-catches leads to the drowning
  deaths of turtles, dolphins and seals.
• Many nations have banned drift net fishing
  altogether. UN banned nets longer than 2.5 km in
  international waters
• Long-line fishing kills turtles, sharks and
  albatrosses (large, with 3.6m wingspan).
• Estimated that 300 000 seabirds a year die as a
  result of diving for the baited hooks.

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Commercial Fishing Damages to Ecosystems

• Bottom-trawling is akin to clear cutting in a
  forests.
• Leaves large swathes of damaged sea bottom
  crushes animals in its path.
• Coral reefs are irreversibly damaged.

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Past Overexploitation

• Chesapeake Bay oyster
• Overharvesting in 18th and 19th century lead to
  collapse of industry in late 19 century.
• Act as algae and bacteria filters on the bottom.
• Resulted in eutrophication and hypoxia of waters.

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Marine Species Management

• Endangered Species Act (ESA)
• Marine Sanctuaries Act
• U.S. Whale Conservation and Protection Act
• International Whaling Commission and Protection
  Act regulates the species that can be harvested
  and sets quotas on the numbers of cetaceans that
  can be harvested

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Marine Species Management

• Magnuson-Stevens Fisheries Management and
  Conservation Act (Magnuson Act) establishes
  Regional Fisheries Management Councils that set
  quotas, size limits and seasons establishes 200
  mile fishing area protects essential habitat
  rebuilds overfished stocks and minimizes bycatch.

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The Magnuson Conservation Act of 1976

• Gave federal government authority to manage
  fisheries
• Claimed the area between 3 and 200 miles offshore
  as the Exclusive Economic Zone

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The Magnuson Conservation Act of 1976

• Designed to eliminate foreign fishing
• Designed to restore and conserve fish

http//images.fws.gov/
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Sustainable Fisheries Act

• The 1996 reauthorization of the Magnuson Act
• Mandates that fish stocks be rebuilt
• Management plans and yields be based on
  scientific data
• Steps be taken to minimize by catch

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Marine Species Management

• Marine Mammal Protection Act
• Convention on International Trade in Endangered
  Species/CITES
• UN Law of the Seas individual countries have
  jurisdiction over the Exclusive Economic Zone
  (200 miles off shore) and sovereignty over the
  sea bed 12 miles off shore allows for the
  Individual Transferable Quotas (ITQ) in which
  allocated quotas can be sold to others.

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Aquaculture
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International Whaling
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Whale Watching