Ocean Test Chapter 6

Front 1

surface zone (mixed layer)

Back 1

upper layer - relatively constant salinity and temperature with depth due to mixing by wind waves and currents. In contact with atmosphere (and oxygen) and exposed to sunlight. Least dense water. About 2% of total ocean volume. Extends to about 150 meters (500 feet) on average but locally can reach depths of 1,000 meters (3,300 ft) or be absent - will see examples later

Front 2

Pycnocline zone

Back 2

density increases with increasing depth. Isolates surface water from denser layer below (deep water). About 18% of all ocean water. Density difference mainly controlled by temperature change.: rapid change in density

Front 3

Deep ocean layer

Back 3

80% of ocean water

Front 4

thermocline

Back 4

rapid change in temperature; warmer surface waters, rapid change in temperature to cold deep waters

Front 5

Deep ocean layer

Back 5

80% of ocean water

Front 6

thermocline

Back 6

rapid change in temperature; warmer surface waters, rapid change in temperature to cold deep waters

Front 7

HALOCLINE

Back 7

lower salinity surface water, rapid change to saltier waters in deep ocean

Front 8

mixed layer

Back 8

Upper depth interval wherein temperature is locally influenced by atmosphere and is relatively uniform due to turbulent mixing by waves, tides, etc

Front 9

thermocline

Back 9

Middle depth interval where temperatures sharply decline; well-developed at low- to mid-latitudes, but more subtle at higher latitudes; C. Thermohaline circulation primarily affects water in the deep oceans below the zone of surface ocean circulation. It produces nutrient-rich waters that rise to the surface during upwelling.A. Changes in water temperature and salinity alter water mass density and cause them to move vertically to reach water masses of comparable density.

Front 10

deep ocean layer

Back 10

Lower depth interval beneath thermocline; lots of subtle temperature variations but persistently less than ~5 °C

Front 11

halocline

Back 11

can strengthen pycnocline (if low salinity at surface) or weaken pycnocline (if high salinity at surface); can strengthen or weaken the thermocline-dominated pycnocline

Front 12

deep currents

Back 12

are very wide and kind of slowly seep along the ocean floors, wending their way between sea floor topography. They are much slower in comparison. A complete circuit around a deep water current could take 2000 years.

Front 13

Isopycnal

Back 13

is a surface of constant potential density of water.

Front 14

isothermal

Back 14

An isothermal process is a change of a system, in which the temperature remains constant: ΔT = 0. This typically occurs when a system is in contact with an outside thermal reservoir (heat bath), and the change occurs slowly enough to allow the system to continually adjust to the temperature of the reservoir through heat exchange

Front 15

isohaline

Back 15

Of equal or constant salinity

Front 16

What are the differing driving forces for surface and deep currents

Back 16

The movement of deep water in the ocean basins is by density(caused by more saline and colder water) driven forces and gravity represented by the blue path(pic below. Red paths reprents surface pushed by wind and much quicker than deep water.

Front 17

What is the ultimate source of the driving forces?

Back 17

Primary Forces--start the water moving
The primary forces are:
1. Solar Heating
2. Winds
3. Gravity
4. Corioli

Front 18

What natural processes alter the surface salinity of the oceans

Back 18

Note surface salinity - low at high latitudes, higher at equator and tropics; processes that decrease salinity such as the continuous input of fresh water from rivers, precipitation of rain and snow, and melting of ice. The weathering of rocks delivers minerals, including salt, into the ocean. Evaporation of ocean water and formation of sea ice both increase the salinity of the ocean

Front 19

Density changes

Back 19

lowest on top, highest on bottom;
-Increases as seawater gets colder
-Increases as salinity increases (as seawater gets saltier)
water gets colder with depth, increasing density
Temperature is major control on density changes
S increases, density increases

Front 20

Why doesn't a thermocline form in polar regions?

Back 20

there isn't a thermocline in polar areas because the temperature at the surface of the ocean, in the surface mixed zone, is similar to the temperature of the water in the deep zone. this happens because there is not much sunlight in polar areas

Front 21

• There are 8 general Taxonomic groupings which are

Back 21

1. Domain
2. Kindgom
3. Phylum (or division for plants)
4. Class
5. Order
6. Family
7. Genus
8. Species

Front 22

• There are 5 kingdoms

Back 22

1. Monera
2. Protista
3. Fungi
4. Plantae
5. Animalia

Front 23

What percentage of the world ocean is involved in surface water

Back 23

2 percent

Front 24

Compare the speed of surface and deep ocean currents

Back 24

Whereas speeds of surface currents can reach as high as 250 cm/sec (98 in/sec, or 5.6 mph) a maximum for the Gulf Stream, speeds of deep currents vary from 2 to 10 cm/sec (0.8 to 4 in/sec) or less."

Front 25

Explain where and why water from the mixed layer sinks into the deep ocean

Back 25

The where is specific high
latitude regions in which the local surface waters are made sufficiently cool (through heat loss to the
atmosphere) and/or sufficiently salty (through earlier/lower-latitude loss of water via evaporation or the exclusion of dissolved solids during sea ice formation) that they become more dense than the surrounding waters. This locally denser surface water spontaneously sink and adjacent surface waters flow in over them, are transformed to higher density by the same processes, and in turn sink downwards.

Front 26

vertical circulation

Back 26

Upwelling and downwelling describe the vertical movements of water masses.

Front 27

stable water column

Back 27

A "stable" water column is one where these "layers" don't mix. This situation might be found in a shallow lagoon that is not subject to tides, currents, etc. that would cause mixing. where less dense (warm) water overlies more dense (cold) water.

Front 28

Unstable water column

Back 28

An unstable water column occurs where denser water overlies less dense water.

Front 29

Thermohaline circulation-

Back 29

a cube of surface water becomes suffieciently cold and salty that it becomes more dense than the surrounding water. Makes a lot of cubes, let them move, build currents. It occurs because temperature and salinity together drive density variations that in turn drive circulation. Carries oxygenated water to the deep ocean

Front 30

brine finger

Back 30

Brine finger sinks
•Outer edges freeze
•Grows as brine flows through hollow straw of the brinicle (combination brine and icicle)
•Once hits sea bottom - higher density flows downslope due to gravity
•Salty cold water kills organisms in path
•Dubbed the "Finger of Death

Front 31

What is the difference between a stable and unstable water column in terms of density

Back 31

An unstable water column occurs where denser water overlies less dense water. ;stable where less dense (warm) water overlies more dense (cold) water.

Front 32

In which (stable, unstable) will you have vertical water flow?

Back 32

vertical motions are inhibited by a stable density structure.

Front 33

What is the temperature range of most deep water masses (less than ___)?

Back 33

5 C

Front 34

Where do the deep water masses originate?

Back 34

The Atlantic

Front 35

Where do the deep water masses originate?

Back 35

atlantic

Front 36

What increases the density of the seawater

Back 36

The freezing of ice

Front 37

What is evaporative cooling?

Back 37

The principle underlying evaporative cooling is the fact that water must have heat applied to it to change from a liquid to a vapor. When evaporation occurs, this heat is taken from the water that remains in the liquid state, resulting in a cooler liquid.

Front 38

Explain how distinctive water masses can exist and be tracked in space and
time

Back 38

where a water mass is an identifiable body of water that has physical properties distinct from surrounding water. traced by amounts of oxygen Young water
-High dissolved oxygen
-Start of conveyor = deep North Atlantic
•Old water
-Low dissolved oxygen
-End of conveyor = deep North Pacific
nitrate, New Water - high nitrate - deep North Atlantic
•Old Water - low nitrate - deep Pacific
tritium
Tritium - bomb produced in 1940s on
-CFC‟s (freon) introduced in 1930s
-Added to atmosphere, then air/sea exchange into the ocean

Front 39

North Atlantic deep water (NADW)

Back 39

is a water mass that forms in the North Atlantic Ocean. It is largely formed in the Labrador Sea and in the Greenland Sea by the sinking of highly saline, dense overflow water from the Greenland Sea. 2nd most dense The watermass can be traced around the southern end of Greenland and then, at a depth of 2000-4000 meters, down the coast of Canada and the United States where it turns a bit east. It continues southeast, past the eastern tip of South America and across the South Atlantic. Its path can ultimately be traced into the Southern Ocean and around the tip of Africa as it mixes with Circumpolar Deep Water.

Front 40

Antarctic intermediate water (AAIW)

Back 40

is a cold, relatively low salinity water mass found mostly at intermediate depths in the Southern Ocean. The AAIW is formed at the ocean surface in the Antarctic Convergence zone or more commonly. called the Antarctic Polar Front zone. This convergence zone is normally located between 50°S and 60°S, hence this is where almost all of the AAIW is formed. 4th most dense

Front 41

Antarctic bottom water (AABW)

Back 41

is a type of water mass in the Southern Ocean surrounding Antarctica with temperatures ranging from -0.8 to 2 °C (31 °F), salinities from 34.6 to 34.7 psu. Being the densest water mass of the World Ocean, AABW is found to occupy the depth range below 4000 m of all ocean basins that have a connection to the Southern Ocean at that level[1]. The major significance of Antarctic bottom water is that it is the coldest bottom water, giving it a significant influence on the movement of the world's oceans. Antarctic bottom water also has a high oxygen content relative to the rest of the oceans' deep waters. This is due to the oxidation of deteriorating organic content in the rest of the deep oceans. Antarctic bottom water has thus been considered the ventilation of the deep ocean.MOST DENSE

Front 42

Mediterranean Intermediate Water (MIW)

Back 42

MIW forms by evaporation of relatively-warm water in the semi-enclosed Mediterranean Sea. Increased salinity results and the water sinks to the bottom of the Sea. Less saline surficial water from the Atlantic Ocean flows into the Mediterranean Sea to replace the lost surface water while the deep warm and salty MIW flows over the sill at Gibraltar and sinks into the eastern North Atlantic Ocean. MIW then continues to flow westward at depths of 1-2 km reaching as far as the island of Bermuda in the western North Atlantic Ocean.3rd most dense

Front 43

global ocean conveyor belt

Back 43

The global ocean conveyor belt is a constantly moving system of deep-ocean circulation driven by temperature and salinity; The ocean conveyor gets it "start" in the Norwegian Sea, where warm water from the Gulf Stream heats the atmosphere in the cold northern latitudes. This loss of heat to the atmosphere makes the water cooler and denser, causing it to sink to the bottom of the ocean. As more warm water is transported north, the cooler water sinks and moves south to make room for the incoming warm water. This cold bottom water flows south of the equator all the way down to Antarctica. Eventually, the cold bottom waters are able to warm and rise to the surface, continuing the conveyor belt that encircles the globe.

It takes almost 1,000 years for the conveyor belt to complete one "cycle."

distributes heat across the globe it is powered by cold salty water sinking and deep water rising to replace it

Front 44

Describe deep water masses in terms of temperature, oxygen and nutrients

Back 44

Young water
-High dissolved oxygen
-Start of conveyor = deep North Atlantic
•Old water
-Low dissolved oxygen
-End of conveyor = deep North Pacific
New Water - high nitrate - deep North Atlantic
•Old Water - low nitrate - deep Pacific

Front 45

What is the densest water mass? Where do you find it in relation to the seafloor?

Back 45

Being the densest water mass of the World Ocean, AABW is found to occupy the depth range below 4000 m of all ocean basins that have a connection to the Southern Ocean at that level[1]

Front 46

What is the estimated age of the oldest deep water? Where is it located?

Back 46

the oldest waters (with a transit time of around 1600 years[citation needed]) upwell in the North Pacific (Primeau, 2005).

Front 47

What are two types of man-made tracers that can be used for ocean water masses?

Back 47

Manmade Tracers
-Tritium - bomb produced in 1940s on
-CFC‟s (freon) introduced in 1930s
-Added to atmosphere, then air/sea exchange into the ocean

Front 48

How do nutrients change from young to old waters?

Back 48

Nutrient along circulation path
-Nitrate is a primary limiting nutrient
-At surface - photosynthesis - nitrate removed from seawater
-At depth - decay of organic matter - nitrate returned to seawater
•New Water - high nitrate - deep North Atlantic
•Old Water - low nitrate - deep Pacific

Front 49

How does oxygen change from young to old waters?

Back 49

Young water
-High dissolved oxygen
-Start of conveyor = deep North Atlantic
•Old water
-Low dissolved oxygen
-End of conveyor = deep North Pacific

Front 50

Types of Upwelling
-Diverging currents (Equatorial and Antarctic)
-Coastal

Back 50

upwelling is a term used to denote water that rises to the ocean's surface from depth. It is caused by wind patterns, and is beneficial because the cold, deep water contains nutrients and dissolved gases, that with sunlight, create favorable conditions in which phytoplankton can photosynthesize. Phytoplankton are the base of oceanic food webs; therefore, areas of upwelling are important ecologically and economically

Front 51

convergence

Back 51

Upwelling along equator results from convergence of NE and SE trades and Ekman transport of surface wates to the north in the northern hemisphere and to the south in the southern hemisphere.

Front 52

Downwelling zones

Back 52

Winds from the south - southerly winds, produce Ekman transport to the east toward the coastline
-Water is pushed downward (downwelling) water piles up at the coast and moves to deeper levels

Front 53

Upwelling zones

Back 53

•Winds from the north - northerly winds, produce Ekman transport to the west away from the coastline
-Water upwells from the deep to replace
deeper water moves up to replace the surface water
Upwelling may be seasonal depending on the strength of the prevailing winds
upwelling is the physical process of bringing up colder, nutrient-rich, deep waters to the surface along coastlines and the equator by physically pulling away overlying surface waters

Front 54

Nutrients

Back 54

Nutrients literally "fertilize" the surface waters and promote biological productivity

Front 55

Antarctic Divergence

Back 55

is a region of rapid transition located in the Antarctic Zone of Southern Ocean between the Continental Water Boundary to the south and the Polar Front to the north. It can be distinguished hydrographically by a salinity maximum below about 150 meters caused by the upwelling of water of high salinity, i.e. North Atlantic Deep Water. Above this salinity maximum the boundaries are blurred by high precipitation and the melting of ice. Its position corresponds reasonably well to the demarcation between the east and west wind drifts which, in the light of Ekman dynamics, at least partially explains its divergent nature.

Front 56

Equatorial Upwelling

Back 56

With water flowing directly away from the equator, both northward and southward, the equator itself has a deficit of water Hence, water from below upwells to fill in the gap. Equatorial upwelling is most prominent in the Pacific Ocean

Front 57

Coastal Upwelling due to Ekman transport

Back 57

Prevailing winds produce Ekman transport (Coriolis effect) in surface waters
most prominent along california and pregon coasts. peru coast

Front 58

Eastern boundary currents - upwelling

Back 58

relatively shallow, broad and slow-flowing. They are found on the eastern side of oceanic basins (adjacent to the western coasts of continents). Subtropical eastern boundary currents flow equatorward, transporting cold water from higher latitudes to lower latitudes; examples include the Benguela Current, the Canary Current, the Peru Current, and the California Current. Coastal upwelling often brings nutrient-rich water into eastern boundary current regions, making them productive areas of the ocean.

Front 59

Normal conditions, El Nino, La Nina

Back 59

An El Nino condition results from weakened trade winds in the western Pacific Ocean near Indonesia, allowing piled-up warm water to flow toward South America. Trade winds weaken/reverse.
•Warm waters flow to Americas.
•Rain in the Americas (Low P)
•Productivity declines
The cooler water temperatures associated with La Niña are caused by an increase in easterly winds. Under normal conditions these winds force cooler water from below up to the surface of the ocean. When the winds increase in speed, more cold water from below is forced up, cooling the ocean surface.
La Nina is cooler than average water

Front 60

How can wind-driven horizontal movement of water induce vertical movement in surface
water?

Back 60

the wind driven horizontal movement of water can sometimes induce vertical movement in the surface water. The movement is called wind induced vertical circulation. Upward movment of water is known as upwelling; the process brings deep, cold usually nutrient laden water toward the surface. Downward movement is called downwelling.

Front 61

How is the Coriolis effect involved in equatorial upwelling?

Back 61

though the coriolis effect is weak near the equator and absent at teh equator, water moving in the currents on either side of the equator is deflectd slightly poleward ad replaced by deeper water. thus equatorial upwelling occurs in these westard flowing equatorial surface currents

Front 62

Types of Upwelling

Back 62

There are three main types of upwelling; equatorial, coastal, and seasonal. Equatorial upwelling is caused by the winds known as the trade winds. The trade winds blow from east to west in the vicinity of the equator. On the northern side of the equator Ekman Transport is to the right (northward), and on the southern side it is to the left (southward). With water flowing directly away from the equator, both northward and southward, the equator itself has a deficit of water. Hence, water from below upwells to fill in the gap. Equatorial upwelling is most prominent in the Pacific Ocean

Front 63

upwelling

Back 63

is an important process because this water from within and below the pycnocline is often rich in the nutrients needed by marine organisms growth

Front 64

What type of winds are needed to induce coastal upwelling in the northern Hemisphere?
Southern Hemisphere?

Back 64

Winds from the north - northerly winds, produce Ekman transport to the west away from the coastline
-Water upwells from the deep to replace
Winds from the south - southerly winds, produce Ekman transport to the east toward the coastline
-Water is pushed downward (downwelling)
Wind-driven currents are diverted to the right of the winds in the Northern Hemisphere and to the left in the Southern Hemisphere due to the Coriolis effect. The result is a net movement of surface water at right angles to the direction of the wind, known as the Ekman transport (See also Ekman Spiral). When Ekman transport is occurring away from the coast, surface waters moving away are replaced by deeper, colder, and denser water.[2]

Front 65

What are the characteristics (temperature and nutrient content) of upwelled water?

Back 65

cooler nutrient rich

Front 66

What happens with the trade winds to trigger an El Nino event?

Back 66

El Nino condition results from weakened trade winds in the western Pacific Ocean near Indonesia, allowing piled-up warm water to flow toward South America.

Front 67

How does El Nino impact the eastern Pacific waters in terms of temperature and
upwelling?

Back 67

An El Nino condition results from weakened trade winds in the western Pacific Ocean near Indonesia, allowing piled-up warm water to flow toward South America. Warmer winters, winter storms. El Nino event decreases the coastal winds. Thus the upwelling from below is slowed

Front 68

Why do Peruvian fisheries decline - often dramatically - in El Nino years?

Back 68

El Nino event decreases the coastal winds. Thus the upwelling from below is slowed Decreases upwelling off of South American coast Negative impacts on productivity, fishes and marine birds and fishermen!

Front 69

How might weather in the western US be affected by El Nino?

Back 69

For southwestern US - more storms and rain = wild weather!. Warmer Winters winter storms