Biol. 317 Lecture Notes - Prof. Eernisse - MLATS Ch. 1

Oceanic organisms
plankton (small drifters)
nekton (strong swimmers)
benthic forms (bottom-dwelling)

Average ocean depth (Table 1.1)
Pacific, Atlantic, Southern,
Indian approx. 4,000 m depth
Baltic Sea 55 m
Persian Gulf 25 m

Planet Earth Oceans
Arctic (90 - 70° N)

Best-known oceans (70 - 50° N)
N. Atlantic plus Hudson Bay,
North Sea, Baltic Sea
N. Pacific including Gulf of
Alaska, Bering Sea, Sea
of Okhotsk

Inland Seas and Historic Shores
(50 - 30° N)
W. Pacific: Sea of Japan,
Yellow Sea
E. Pacific: West Coast, incl.
Puget Sound, Columbia R.,
San Francisco Bay
W. Atlantic: Georges & Grand
Banks (shallow)
E. Atlantic:
Strait of Gilbraltar
(22 km wide, 320 m)
-> Mediterranean Sea
(to 5,100 m)
Bosporus Strait
(1 km wide, 40 m)
Black Sea (to 2,000 m)
Caspian & Aral Seas
(land-locked, 1/3 as
saline as oceans)

At these latitudes, we emphasize:

Cool to Warm Temperate

Warm Ocean Deserts (30 - 10° N)

Barren warm surface waters
rotate clockwise - gyres
Sargasso Sea (Sargassum)
N. Pacific Gyre

10° N to Antarctica
Simple coastlines
No marginal seas

81% of S hemisphere is ocean
61% of N hemisphere is ocean

Line of Life (10° N to 10° S)

Indo-Pacific - Africa to
E. Pacific Barrier (no islands)

Site of El Nino/Southern
Oscillation (ENSO)
W. Equatorial Pacific warm
spot - spreads eastward

Peru warms
spreads N.
devastates coastal marine life
of tropical W. America
disrupts weather worldwide

Living Relicts (10 - 30° S)
wide, coastal currents,
barren in between
Unknown Oceans (30 - 50° S)
"Roaring Forties"
Great Southern Ocean (50 - 70° S)
current sweeps eastward
Antarctic Convergence 55° S
krill, baleen whales

Ocean floor

Forms by spreading
Youngest in middle

Study Figs. 1.7, 1.8 - Plate tectonics
Spreading center (phosphorus)
Mid-oceanic ridge
Subduction zone
Oceanic/Continental plates

Continental margin
Shelf, slope, rise
Submarine canyons - enormous
turbidity currents >100 km/hr

Abyssal plain, hills

Seafloor sediments
terrigenous - from land
ooze - biogenic - organisms
"marine snow"
calcareous or siliceous
recycled as they sink
CCD - 4,700 - 4,200 m
"snow line"
abyssal clay - fine non-gritty
manganese nodules

Coral reefs (Fig. 1.10)
Charles Darwin proposed model
Example of geological
Fringing reef ->
Barrier reef and lagoon ->
Atoll and lagoon

Tilt/Temperature of Planet

angle of tilt 23.5°

tropics - 23.5° N to 23.5° S
sun directly overhead 2X a year
days and nights about 12 hrs

temperate zones - 23.5° to 66.5°

Ice caps are recent phenomena

Ancient earth was much warmer