- Liquid surface water (vs. other planets) - Most organisms = water - Absorbs Carbon Dioxide - Up to 70% breath = oceanic

1. Crust overlap/gaps—continental shelf 2. Mechanism wrong (moon pull)

Exam One Flashcards by Yahya C

Oceanography

Scientific study of entire marine region; also Marine Science (includes lakes, ponds—broader)

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Four Disciplines of Oceanography

Geological
Chemical
Physical
Biological

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Scientific Method Cycle

Observation
Testing
Drawing Conclusions
(Repeat)

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How did the atmosphere form?

1st: leftover gas/dust from nebula cloud (got blow away)
2nd: Interior gas rises up (lighter)—outgassing—and then gets colder, condenses, falls down; accumulate in lowest parts of Earth (also trace amounts from comets)

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When did the first permanent oceans form?

More than 4 billion years ago; not much different than now

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Why is the ocean salty?

Water was slightly more acidic (lots of chlorine); as it ran down it dissolved minerals and carried them with it

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3 Theories of Life’s Origin

Delivery—from comets/meteors
Hot Oceanic Springs—extreme surroundings created life
Minerals—acted as catalysts for life

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1st Preserved Life Form

Primitive bacteria (eukaryotes) around 3.5 billion years ago

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Why Did Life Originate In The Ocean?

Early Earth had capabilities of growing life; “building blocks” and suitable environment concentrated in oceans

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Radiometric Dating Premise

Based on the assumption that Earth’s processes take a long time, are constant (measure rock ages by calculating half-lives)

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Specialties of Ocean

Liquid surface water (vs. other planets)
Most organisms = water
Absorbs Carbon Dioxide
Up to 70% breath = oceanic

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Oceans vs. Seas

Seas—smaller, shallower, mostly enclosed by land
Oceans—bigger, interconnected

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Plate Tectonics

Theory: lithosphere broken up, pieces move around (mostly) horizontally like icebergs; interactions develop surface features

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Continental Drift Evidence

Continents = jigsaw puzzle
Rock sequences (mountain chains)
Fossils (split across continents)
Glacial Deposition
Ocean Drilling (older farther from ridge)
Paleomagnetism (mirrored stripes on both sides of ridge)
Ocean Basin Features (Hess proposed sea-floor as mechanism)
Satellites (see plates moving/time)

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C.D. Anti-Evidence

Crust overlap/gaps—continental shelf
Mechanism wrong (moon pull)

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Divergent Boundaries

Move apart, create space for magma up-flow
- rift valley, mid-ocean ridges

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Mid-Ocean Ridge

Mountain chain (above ground in Iceland); rises to 2.5 km (1.5 mi) above floor; wraps around globe 1 1/2 times (46,000 mi); I,000 km wide; 23% of Earth’s surface

Convergent Boundaries

Subduction (OO/OC/CC);
- deep-ocean trenches, subduction zones, volcanic/island arcs

Passive vs. Active Margins

Passive—no major tectonic activity, not near boundary (rise)
Active—mostly convergent, lots of activity

Continental Rise

Part of passive margins; formed by successive turbidity currents (fans)

Abyssal Plains

Formed by sediment blanketing irregularities; passive margins (active = trench); mostly in Atlantic/Indian (no trenches, smaller in size)

Bathymetry Evolution

Rope
Echo Soundings (ping—post WWII)
Satellites (1970s)

Lithogenous Sediment

Weathered rock bits; majority quartz; most common type; farther from shore = more fine)

Neritic/Pelagic

Neritic = shelves, shallow water near islands (near shore); coarse
Pelagic = deep-ocean basins; fine

Biogenous Sediment

Shells (tests), bones, teeth; need to be at least 30%; calcium carbonate/silica based; *carrots*

CCD

Calcite compensation depth—colder temperature, higher pressure, more acidity causes calcite/cc to readily dissolve

Hydrogenous Sediment

Formed through precipitation (sulfides, phosphates, carbonates, evaporates); *sugar*, little, spread out

Cosmogenous Sediment

Extraterrestrial; small or big; 22,000 lbs/year

Coastal Regions

1. Coast—no seawater (but marine-only features 2. Coastline—farthest storm water 3. Shore—low-tide shoreline to 2 4. Berm—beach; sandy part 5. Beach—to end of underwater features

Winter/Summer Beaches

**Winter**—heavy flow: less berm (erosional) **Summer**—light flow: wide berm (depositional)

Longshore Drift/Current

Movement parallel to shore **Current** = water **Drift** = sand, people, objects

Sea Level Change

1. Land—tectonic uplift/isostatic adjustment 2. Sea (Eustatic = around world)—sea floor spreading rates (fast = taller)/ice ages (less water in oceans)

Water

Polar molecule; 104.5 angled bond; covalent bonds/hydrogen = 1. Universal solvent (weakens ions) 2. Adhesion/cohesion

Heat Capacity/Specific

Raise temp. by 1 degree/raise temp. of one gram by 1 degree

Latent Heat

Energy needed to convert water between stages (no temp. increase)

Salinity

Total # of solid material dissolved in water; avg. 3.5% - boil, measure Cl ions, salinometer (electrical conductivity)

Decrease Salinity

1. Precipitation 2. Runoff 3. Icebergs melting 4. Sea ice melting

Increase Salinity

1. Sea ice forming 2. Evaporation

Ocean Currents

1. Temperatures (more cuz range) 2. Salinity

Pycnocline

Layer of rapidly changing (density) water; barrier between surface/lower water (1,000 m); in low latitudes only (in high not much difference)

Ocean PH

More alkaline (8.1 surface, 7.6 depths); cc shells dissolve = less acidity