Review Outline for First Midterm (100 points)
Fall 2008
Review all of your lecture notes with this outline and your two lecture quizzes.
I. The World Ocean
A. Oceans cover about 70% of planet Earth's surface
B. All oceans are interconnected.
C. Four main oceans - (1, 2, and 3 run together near Antarctica)
1. Atlantic
2. Pacific
3. Indian
4. Arctic
D. World Geography Concepts
1. Most continental land masses are in northern hemisphere
2. The southern hemisphere is about 80% ocean
3. Earth's continents include North America, South America, Europe, Asia, Africa, Australia and Antarctica
4. North polar views and south polar views of Earth give more accurate view of polar areas.
5. Zones on Earth due to temperature
a. Tropical - 30 degrees North to 30 degrees South = warmest
b. Temperate - 30 degrees to 60 degrees North and South
c. Polar - 60 degrees to 90 degrees North and South = coolest
E. Oceanic Topography (most [80%] of the ocean bottom is abyssal plain and undersea mountain ranges)
1. Continental Shelf (8%)
2. Continental Slope
3. Abyssal Plain (50%)
4. Oceanic Ridges and Rises (30%)
5. Trenches (2%)
Note: 10% other = continental slope, seamounts, guyots
II. Classification of Marine Environments
A. By space
1. Pelagic (in the water)
a. Neritic - in the water over the continental shelf
b. Oceanic - in the water over the deep sea (abyssal plain, oceanic ridges/rises, trenches)
2. Benthic (on the bottom or on a solid surface)
a. Inner shelf
b. Outer shelf
c. Bathyal - continental slope (200 to 3-6,000 m)
d. Abyssal - abyssal plain (3-6,000 m)
e. Hadal - trenches (below 6,000 m to 11,000+ m)
B. By light (from Productivity lecture)
1. Photic (200m maximum) depth of light penetration needed for photosynthesis
2. Aphotic - below photic zone (no plants can live here)
III. Seawater - marine critters (life forms) affected by seawater. Life forms are made of cell(s) which are very similar no matter what species, whether simple or complex, unicellular or multicellular. Cells are bounded by a differentially permeable cell membrane.
A. Salinity
1. Most ocean water is 35%o (parts per thousand) dissolved salts
2. Variations
a. Range from 0 at river mouths to 37%o in central Atlantic
b. Salts are varied (7 major and 5 minor ions)
(1) Most of the salts are Na (sodium) and Cl (chlorine) [NaCl = sodium chloride = table salt]
(2) All salts always in same proportion to each other
c. Salinity varies little over time in one location
(1) Decreases due to precipitation, river run-off of water, and ice thawing
(2) Increases due to evaporation, river run-off of salts (over new rock areas), and localized freezing
3. Effects on marine organisms from osmosis
a. Osmosis = movement of water across cell membrane to establish an equilibrium (relative to salt content)
(1) Medium isotonic to organism - equal flow of water in and out of cells (in organisms without control)
(2) Medium hypotonic to organism - cells gain water and explode (in organisms without control)
(3) Medium hypertonic to organism - cells loose water and collapse (in organisms without control)
b. Organisms respond
(1) Osmotic conformers - poikilosmotic - non-regulators
(a) No control mechanism
(b) Same salt concentration as environment
(c) Example: marine plants, invertebrate animals
(d) Don't do well if moved from their normal salinity
(2) Osmotic regulators - homeosmotic
(a) Control internal salinity
(b) Example: marine vertebrates (fish, mammals)
(c) Salmon in seawater (medium is hypertonic) tend to dehydrate so they drink constantly and special cells on gills excrete salt (called chloride cells). In freshwater (medium is hypotonic) they tend to explode so they don't drink and urinate frequently.
(d) Can move between different salinities easily
B. Temperature
1. Seawater increases in temperature due to the sun (little daily change due to the stability of water, but there are seasonal changes)
a. Seasons more pronounced at the poles than the relatively stable equatorial region.
b. Vertically - sun's heat increases the surface temperature producing a three layered ocean:
(1) Upper mixed layer
(a) All one temperature (-2 to +30 degrees C depending on latitude)
(b) Depth 0 to 200 meters depending on latitude
(c) Small volume of the oceans
(d) Affected by the seasons
(2) Main thermocline
(a) Rapid decrease in temperature with depth
(b) From bottom of mixed layer (0-200m) to deep water
(c) Variable (stable in tropics, seasonal in temperate, not present in polar) volume of oceans
(d) Affected by seasons as it shifts up and down
(3) Deep water (bottom water)
(a) All one temperature (-2 to +5 degrees C)
(b) Below main thermocline (at the surface near the poles)
(c) Greatest of volume of oceans
(d) Not affected by seasons
2. Effects on organisms
a. Species specific tolerances - most organisms can adapt to slow changes (easier to adapt to cooler water than to warmer water)
(1) Warmer - cellular reactions speed up, metabolism increases
(2) Cooler - cellular reactions slow down, metabolism decreases
b. Organisms respond
(1) Cold blooded (poikilothermic) - non-regulator
(a) Lack any temperature controls
(b) Example: most invertebrates, plants, some fish, reptiles
(c) Restricted to areas within their tolerance range
(2) Warm blooded (homeothermic) - regulator
(a) Control internal temperature, maintain constant temperature
(b) Example: most marine vertebrates (some fish, mammals, birds)
(c) Can move between water masses of varied temperature, less restricted range
C. Density of water masses important in layering (more dense water sinks) - topic covered in Temp/Sal lab
1. Temperature increases cause water to be less dense (greater effect than salinity or pressure)
2. Salinity increases cause water to be more dense
3. Pressure increases cause water to be more dense
D. Dissolved gases - concentration increases in cooler water, cycles related to cellular respiration and photosynthesis
1. CO2 (carbon dioxide) generally abundant at all depths from animal and plant cellular respiration
2. O2 (oxygen) often a limiting factor (here range is from 0 to 20 ppm dissolved oxygen)
a. Increases in dissolved oxygen
(1) Photosynthesis by plants - biological, greatest effect
(2) Diffusion at surface (air contact, wind) - physical, small effect except right at the surface during windy or stormy days
b. Decreases in dissolved oxygen by use of plants and animals in cellular respiration
3. Ecological recycling of oxygen and carbon dioxide by cellular respiration (carried on by both plants and animals, uses oxygen and produces carbon dioxide) and photosynthesis (carried on by plants, uses carbon dioxide and produces oxygen)
a. Cellular Respiration is Cell Food + O2 = Cell Energy + CO2 + H2O
b. Photosynthesis is CO2 + H2O (in the presence of light) = Cell Food + O2
E. Dissolved nutrients (nitrogen = N, phosphorous = P, potassium = K, etc.)
1. Fertilizers - important for plant growth = nutrients
a. increases from animal feces and decomposition (bacteria, fungi)
b. surface water often lacking as feces and dead matter settle to the bottom and decompose there
c. surface water often separated from subsurface water by thermocline (seasonal in temperature and marginal polar regions, constant in tropics)
2. Silica in marine environments for diatoms
F. pH (measure of acidity or alkalinity)
1. Ocean water has an excellent buffering system with the interaction of carbon dioxide and water so that it is generally always 7.5 to 8.5
2. If seawater pH is out of normal range then there is something terribly wrong, probably a major acid or alkaline spill
IV. Seawater Movements
A. Winds - primary force producing currents (winds named for direction they came from)
1. Sun's energy heats air
a. Air heated more at equator
b. Hot air rises
c. 3 cell wind pattern created by hotter air rising and cooler air falling (weather cells)
(1) Air rises at 0 and 60 degrees North and South
(2) Air falls at 30 and 90 degrees North and South
d. 3 circulating weather cells (Hadley Cells near equator = equatorial, Ferrel cells in the temperate areas = mid latitude, and Polar Cells in the polar areas) in each hemisphere (North and South)
2. Coriolis effect (moving masses veer right in northern hemisphere and left in southern hemisphere) causes air movement in cells (as observed from the surface of Earth) to move in east-west direction
a. Trades (0-30 degrees North and South) (easterly wind, blows east to west)
b. Westerlies (30-60 degrees North and South) (westerly wind, blows west to east)
c. Polar Easterlies (60-90 degrees North and South) (easterly wind, blows east to west)
B. Currents - mass flow movements of water (currents named for direction they go)
1. Major surface currents are clockwise gyres in northern hemisphere, counterclockwise in southern hemisphere
a. Causes
(1) Wind (greatest surface area around equator with Trades moving water east to west) piles water up on western side of ocean
(2) Continental land mass obstructions
(3) Coriolis force causes water moving in a straight line to veer right in the northern hemisphere and left in the southern hemisphere
b. Types of gyre currents
(1) Western Boundary Current (on western side of ocean)
(a) Goes North in northern hemisphere, South in southern hemisphere
(b) High energy current - rather narrow, deep, fast
(c) Warm water (from equator)
(d) Example: Gulf Stream in Atlantic off East Coast of USA
(2) Eastern Boundary Current (on eastern side of ocean)
(a) Goes South in northern hemisphere, North in southern hemisphere)
(b) Low energy current - rather wide, shallow, slow
(c) Cold water (from poles)
(d) Example: California Current in Pacific off West Coast of USA
(3) Center of gyre
(a) May be calm like Sargasso Sea in Atlantic (goes round and round)
(b) May have lateral currents from winds
(c) Generally saltier than other areas - more evaporation and less mixing
(4) West Wind Drift - only current that goes around Earth uninterrupted by continents near Antarctica
2. Major subsurface currents
a. Upwelling - wind on surface blowing strongly causes deep (nutrient rich) water to come to the surface and mix, this is a seasonal phenomena in selected areas
(1). Causes high biological productivity
(2) Examples: Equatorial area off Peru, western USA
b. Slow subsurface circulation of water sinking at the poles (coldest) creeping across ocean bottom and layering due to density near equator (400 year cycle) = thermohaline circulation (due to density differences in seawater caused by temperature and salinity)
C. Waves (height, amplitude, crest, trough, wavelength) will not be on exam one - we will cover this topic in the lab entitled "Currents, Waves and Beach Profile" and you will be tested on this in a lab quiz.
V. El Niņo (a phenomenon and major oceanographic event)
A. General
1. Usually begins around Xmas time (name means "the Child" in Spanish and stands for the Christ Child) usually centered on the Galapagos Islands
2. Occurs every 3 to 10 years (hard to predict) - usually lasts a few months
3. Trade winds in eastern tropical Pacific fail just at and below the equator
4. Lack of forces to create normal oceanic gyres in the South Pacific that cause Peru (Humbolt) Current to bring cold water up South America (eastern boundary current) from South Pole region -gyre (South Pacific) slows down in El Niņo
B. Effects on life forms living in this area
1. Sea surface temperatures increase
a. Strong thermocline as equatorial sun warms surface water (locking out nutrients)
i. life forms that cannot tolerate the temperature increase die or leave
ii. plant life that cannot tolerate the lack of nutrients dies
b. No upwelling (no nutrients replenished at surface)
i. plant life that cannot tolerate the lack of nutrients dies
ii. animals starve up the food chain (web) or leave
2. Rainfall increases as warmed water evaporates and condenses to form clouds and is not blown away by winds
a. fluctuations in salinity affect life forms in ocean
b. increased rain on land increases land plant growth (normally a desert on land)
3. Extreme (strong and long) El Niņo causes water build up (up to 6 feet) on western side of Pacific Ocean to "slosh" back to the east but only if long (severe) El Niņo = Kelvin Wave
a. Sea levels rise off Peru (Galapagos) - changing shorelines
b. Sea levels fall off Australia - exposing the Great Barrier Reef, killing coral
C. If condition lasts a long time heat is transferred north and south in ocean and changes in sea surface temperature are transferred to air. This causes changes in global weather (rains in draught areas, storms in calm areas) - unpredictable, global effects that can be helpful or devastating.
D. The 1982-83 El Niņo was one of the two most severe in recorded history (lasting over a year) (1997 was another severe El Niņo)
1. In 1982-83 seawater warmed 30 degrees F in some areas killing marine life there to 40-70 feet (thermocline) in Galapagos (many coral species died)
a. Without much life in the upper waters many species were affected that depended on this as a food source
(1) Fish-eating sea birds (some species did not reproduce at all that year, other species left)
(2) Algae eating marine iguanas (most died of starvation as they feed on algae to 30 feet only and most edible plants were dead to this depth)
(3) Sea Lions became thin and diseased as there were few fish to eat
2. In '82 & '83, with torrential rains, the normally desert vegetation became a lush undergrowth (6x yearly rainfall) in Galapagos (another strong one was in 1997)
a. Land iguanas had lots to eat and became fat
b. Finches had lots to eat and reproduced about 3-4 times as many offspring as usual - Extra babies died of starvation the next year or during floods
E. La Niņa is the opposite of El Niņo and is the situation with colder water and stronger than normal Trade Winds
F. After an El Niņo conditions adjust back to normal - if the El Niņo has been exceptionally strong (like '82-'83) it may take a few years
G. Since the severe 1982/83 El Niņo there are monitoring buoys across the equatorial Pacific Ocean to pick up all hints of an El Niņo.
1. These are monitored by USA NOAA (National Oceanographic and Atmospheric Administration)
2. www.elnino.noaa.gov will give you lots of current information
VI. Plate Tectonics & Continental Drift (theory of continents moving on Earth relative to each other)
A. Crust - two types
1. Continental - granitic, under the continents, continental shelf and continental slope
2. Oceanic - basaltic, under the abyssla plains, oceanic ridges and rises, most trenches
B. Trench System
1. Narrow wrinkles in the crust extending to depths over 11,000 meters
2. Many trenches circling the Pacific Ocean
C. Oceanic Ridges and Rises
1. One mountain range under oceans running around Earth
2. Runs down the center of the Atlantic Ocean = Mid Atlantic Ridge
3. Runs off to the side of the South Pacific and up under Baja = East Pacific Rise
D. Earthquakes
1. Deep and shallow in the crust at trenches
2. Shallow in the crust at ridges and rises
E. Crustal Plates
1. 12 major portions of earth's crust move relative to each other
2. Some plates oceanic crust only
3. Some plates oceanic crust that carries continental crust
F. Continental Drift
1. Continental crust pieces moved around by plate movement (plate tectonics)
2. 200 million years ago all continental pieces together as one super continent = Pangaea
3. Mechanism for movement is seafloor spreading
a. New crust made at oceanic ridges or rises = spreading center (plate divergence)
b. Extra crust remelted under trenches = subduction zone (plate convergence)
G. The theory of plate tectonics in diagrammatic form, the cross section of the Pacific Ocean and the Atlantic Ocean (with the Pacific, Nazca, American, and African Plates that I put on the board as a summary ... includes Hawaii as a 'hot spot').
VII. Islands
A. Continental
1. Near continents or on continental shelf (may once have been connected to land)
2. Continental crust
3. Example: Greenland, Madagascar, our Channel Islands
B. Oceanic
1. Anywhere - result of hot spot, oceanic ridge, or plate boundary
2. Oceanic crust
3. Example: Hawaii (Hot Spot), Surtsey near Iceland (Mid Atlantic Ridge), Galapagos (plate boundary)
C. Island Arc
1. On continental side of deep sea trench
2. Andesitic rock (continental and oceanic crust)
3. Example: Aleutians
VIII. Productivity
A. Energy flow in ecosystems depends on the sun and recycling systems of gases and decomposers
1. cellular respiration and photosynthesis recyle oxygen and carbon dioxide
2. plants = producers = autotrophs
3. animals = consumers = heterotrophs
a. herbivore
b. carnivore
c. omnivore
4. decomposers recycle dead matter by rotting cells and releasing nutrients
B. Energy flow only 10% efficient in food webs and chains (average) at each step (trophic level)
1. Trophic Pyramid illustrates this - marine trophic phyramid with either phytoplankton or macro algae (seaweeds) as the base
a. Phytoplankton based marine areas occur everywhere on earth (open ocean and coastal) and account for most of the marine productivity
b. Macro algae based marine areas occur only in coastal areas in most places
2. 100 pounds of producers can support 10 pounds of herbivores, 10 pounds of herbivores can support 1 pound of a carnivore.
C. Primary productivity = plant growth = photosynthesis
1. Most measurements of productivity are of rates of photosynthesis
2. Standing crop is total amount of plant material (weight, volume) as a base, this may also be used but is destructive to actually measure.
D. Factors affecting productivity
1. Light - must be in photic zone (maximum depth of photic zone on Earth is 200 m)
a. latitude
b. atmospheric absorption
c. angle of the sun's rays (too small then all light bounces off ocean surface)
d. depth of the water (light filtered out as you go deeper)
2. Nutrients - limited if no upwellings or a strong thermocline
3. Grazing causes a decrease in standing crop
E. Global productivity
1. Zones
a. Tropics - stable, always warm
(1) Year round thermocline - little surface nutrients
(2) Year round light levels for plant growth
(3) Constant low productivity
(4) Nutrients limited all year
b. Temperate - seasonal
(1) Summer thermocline so no nutrients in summer
(2) Light levels in Spring, Summer, and Fall enough for plant growth
(3) Two blooms in Spring and Fall
(4) Nutrients limited in Summer, light limited in Winter
c. Polar - seasonal
(1) Never a thermocline - always nutrients
(2) Light levels only in summer enough for plant growth
(3) One bloom - summer
(4) Light limited except in summer
2. Upwelling Areas
a. Open ocean areas have the least productivity per surface area
b. Coastal areas are more productive than open ocean areas per surface area
c. Upwelling areas (whether open ocean or coastal) are the most productive
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