The oceans cover 71% of the earth’s surface
The Four Large Ocean Basins
The Arctic Ocean Shallow Low Salinity
Diluted by large rivers
About half covered with permanent ice
Low species diversity Hallmark animals include
polar bear and walrus
Walruses were once common around the perimeter of the Arctic, but large-scale hunting has
greatly reduced their numbers
Features of Atlantic Ocean
Georges and Grand Banks Great expanses of
shallow water that supported cod fisheries for centuries
North Sea One of most
thoroughly studied marine waters on earth
The Manatee
The Pacific Ocean
(36,163 ft.)
Feb 1977 the submersible Alvin dived to a depth of 2500m over the Galapagos ridge. That is when hydrothermal vents were discovered.
The Galapagos Ridge
Equator
The deep sea submersible Alvin
Hydrothermal Vents
Water is heated by magma and absorbs metals from earth’s crust
Marine Iguana
The Indian Ocean: Relict Species
Coelacanth Stromatolites
Drive from Perinet to Toamasina. Fly to Maroantsetra. Drive to Relais du Masoala Hotel. Two hour boat Ride to Ecolodge on Masoala Peninsula.
Hotel Ecolodge
The Four Large Ocean Basins
The Ocean Basins Are Interconnected The World Ocean
The Antarctic Circumpolar Current (ACC) Formed about 25 MYA
when Australia and South America separated from Antarctica
Isolated the Antarctic continent from warmer waters to the north and is partially responsible for the formation of Antarctica's permanent ice cover.
The northern boundary is called the Antarctic Convergence or the Polar Front.
The Southern Ocean
The Southern Ocean
Antarctic Convergence Divides warm surface
waters of Atlantic, Pacific, and Indian Oceans from cold polar waters.
Abundant krill Summer feeding area
for baleen whales
Large Scale Distribution of Antarctic Krill
Krill are a keystone species in the Antarctic food web. Krill are crustaceans with several larval stages in their life cycle. Some of the larval stages feed on algae that grow on the lower surface of sea ice. One of the factors that determines the annual abundance of krill is the extent of sea ice in winter. Global warming may have significant impacts on krill abundance.
The Antarctic Convergence
Light E Food E
The Sun
Phytoplankton
Krill – Euphausia superba
Baleen Whales Crabeater Seals Leopard Seals Adelie Penguins Chinstrap Penguins Gentoo Penguins
Photosynthesis
The top predators of the Antarctic Peninsula are seabirds and seals.
The Crabeater Seal is a Krill Specialist
Crabeater seals are krill specialists. Their entire “terrestrial” existence is spent on ice floes, not land. Their populations may be increasing due to an increase in krill abundance associated with the decline of baleen whales.
The Structure Of The Earth Core
Mostly iron High Temperature Solid inner and liquid
outer core Swirling motion of
liquid outer core believed to be what creates earth’s magnetic field
Polarity reversals about every 300,000 years
The Structure Of The Earth
Mantle Solid High temperature –
Near the melting point of rocks
It flows Iron and magnesium
silicates
The Structure of the Earth
Crust Outermost layer Extremely thin Composition varies
Continental Versus Oceanic Crust
Continental Granite Low density Light Thick (20 – 50 km) Can be old (3.8by)
Note: Density = Mass Volume
Oceanic Basalt High density Dark Thin (5 km) Young (<200my)
The Lithosphere
Lithosphere = Outer layer of mantle + Crust
The pates involved in plate tectonic motion are plates of the lithosphere
Plates of the Lithosphere
Principles of Plate Tectonics
The plates of the lithosphere carry the continents like passive passengers Pangaea
• 200 million years ago all the continents were combined into one landmass
Pangaea
The average rate of plate movement today is between 2 and 12 centimeters (1 an 5 inches) per year
East Pacific Rise
Mid-Atlantic Ridge
Plate Tectonics
Subduction Zones and Trenches
Oceanic Plate: Label Continental Plate: Label
Collision Between Two Oceanic Plates
Island arc at trench Volcano rising from hotspot
__________ Boundary
Examples?
Divergent
Divergent Boundaries
__________ Boundary
Trenches and volcanoes are associated with this type of boundary
Convergent
Oceanic – Continental Convergence
Peru – Chili Trench Andes Mountains
Transform Boundaries
The San Andreas Fault occurs at a transform boundary
Evidence For Plate Tectonics
Fit of continents Matching sequences of rocks Fossils Mid-Ocean Ridges
Sediment gets (thicker/thinner?) as you move away from crest of mid-ocean ridge
Rocks get (older/younger?) as you move away form the ridges
Fit, Rocks, and Fossils
Mesosaurus Fossils Link Africa and South America
Geological Provinces of the Ocean
Continental Margins
Continental Shelf
Gently sloping Exposed during times
of low sea level Biologically richest part
of ocean 8% of ocean surface
area Submarine canyons Ends as shelf break
The Continental Shelf Off Of Los Angeles
Continental Slope
Steep Edge of continent Along active margins
the slope descends into submarine canyons
Continental Rise
Sediment deposits on ocean floor
Found on passive margins (not active margins)
The Continental Shelf Off Of Los Angeles
Active Versus Passive Margins
Active • Trenches • Narrow shelves • Rocky shorelines
Passive • Flat coastal plains • Wide shelves • Trailing edge of continent
Mid-Ocean Ridges
Seamounts = Submarine Volcanoes Tablemount = Flat Topped Seamount
Copepod
Cyanobacteria (P/S)
Arrow worm
Plankton
The Sun 1-2% Efficient
10% Efficient
10% Efficient
10% Efficient
10% Efficient Herbivorous zooplankton Diatoms and Dinoflagellates
Copepods
Arrow Worms
Fish
Plankton versus Nekton
Plankton Weak swimmers Ride the ocean
currents
Nekton Strong swimmers Can swim against the
currents
Phytoplankton versus Zooplankton
Photosynthetic (P/S)
Autotrophic
Diatoms and Dinoflagellates
Nonphotosynthetic (non-P/S)
Heterotrophic
Copepods
The Sun 1-2% Efficient
10% Efficient
10% Efficient
10% Efficient
10% Efficient
Small carnivorous fishes
Large Carnivorous Fishes
Herbivorous Zooplankton
Brown Pelican
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