Ocean Layers

Near the equator, what occurs resulting in lowered salinity.

Greater rainfall

The equator and high latitudes (near the poles) have what salinity?

Low salinity

The maximum density of pure water is?

1gm/cm3

As salinity increases, what happens to water density?

It increases

At what temperature does pure water freeze into ice?

0 degrees Celsius or 32 degrees Fahrenheit

In a typical seawater sample of 1000 grams (1 kilogram), the seven primary salts that would be present, in order from largest amount to smallest amount would be:

1. Chloride (Cl-): 18.98g (54% of solution weight) 2. Sodium (Na+): 10.56g (30% of solution weight) 3. Sulfate (SO42-): 2.65g (8% of solution by weight) 4. Magnesium (Mg2+): 1.28g (4% of solution by weight) 5. Calcium (Ca2+): 0.40g (1% of solution by weight) 6. Potassium (K+): 0.38g (1% of solution by weight) 7. Bicarbonate (HCO-): 0.14g (< 1% by weight)

What are the 5 zones in the ocean?

1. Epipelagic Zone 2. Mesopelagic Zone 3. Bathypelagic Zone 4. Abyssopelagic Zone 5. Hadalpelagic Zone

The ocean has how many primary layers?

3

Water reaches it maximum density at what temperature?

4 degrees Celsius

On average, though, the thermocline exists between?

50-1,000m

The major seawater constituents are seven dissolved salts that account for over what percent of all dissolved substances in seawater.

90%

In what two general parts of the globe is salinity typically lowest?

At the equator and high latitudes.

The pycnocline is a function of what?

Because density is a function of temperature and salinity, the pycnocline is a function of the thermocline and halocline.

What is the Mesopelagic Zone?

Below the epipelagic zone is the mesopelagic zone, extending from 660 feet (200 meters) to 3,300 feet (1,000 meters). The mesopelagic zone is sometimes referred to as the twilight zone or the midwater zone as sunlight this deep is very faint. Temperature changes the greatest in this zone as this is the zone with contains the thermocline.

What is the thermocline?

Below the surface layer is the thermocline, the layer between warm surface water and cold deep ocean. Its size varies based on latitude and season, but it will rarely occur deeper than 1,000m2. In this layer, temperature changes rapidly with depth.

What is the deep ocean layer?

Below the thermocline is the deep ocean. Water here is cold and dense. Temperature and salinity tend to remain relatively constant below the thermocline.

Reminder question: This term refers to the capture and storage of carbon:

Carbon sequestration

Below the pycnocline or thermocline, temperature and salinity are relatively what?

Constant

High-density water is generally what?

Cooler and more saline.

In which oceanic layer is most of Earth's water located?

Deep ocean (or below thermocline)

The ocean forms layers because the water has different what throughout?

Density

What property of water is determined by salinity and temperature?

Density

Geographically, salinity varies as a function of what?

Evaporation, precipitation and freshwater input (e.g., river outflow, ice melt).

The mid- latitudes have what salinity?

High salinity

What 2 elements are the most abundant in seawater?

Hydrogen and oxygen are the most abundant elements in seawater.

Pressure also affects seawater density, but only where in the ocean?

In the deepest parts of the ocean.

Why would warm water stay on the ocean surface?

It is less dense than colder water and essentially "floats" on the denser layers.

The maximum density of sea water occurs at what point?

Its freezing point

The density of ice is what compared to water?

Less than water

At high latitudes, what contributes to lower salinity levels?

Melting ice

Is Salinity homogenous throughout the ocean?

No.

The freezing point of sea water depends on its what?

Salinity content (increase in salinity, decrease in freezing point)

What is Salinity?

Salinity is a measure of the total concentration of dissolved (inorganic) solids (e.g., salts) in water.

Name one piece of technology used to measure salinity.

Satellite, CTD, salinometer are all acceptable responses.

The thermocline size and depth varies with what?

Season and latitude

What is seawater?

Seawater can be thought of as a solution. The dissolving agent or solvent is liquid water (H2O) and the materials dissolved in water, such as salt, are the solutes.

Water with higher density does what?

Sinks to the bottom

Water with lower density does what?

Sits on the top

In the tropics, the thermocline is mainly what?

Stable

What 2 things affect density?

Temperature and salinity both affect density.

The speed of sound in the ocean varies with what?

Temperature, pressure, and salinity and therefore will also vary in the different ocean layers.

What is the Abyssopelagic Zone?

The Abyssopelagic Zone (or abyssal zone) extends from 13,100 feet (4,000 meters) to 19,700 feet (6,000 meters). It is the pitch-black bottom layer of the ocean. The name (abyss) comes from a Greek word meaning "no bottom" because they thought the ocean was bottomless. Three-quarters of the area of the deep-ocean floor lies in this zone. The water temperature is constantly near freezing and only a few creatures can be found at these crushing depths.

What places have the highest salinities on Earth?

The Red Sea and Mediterranean Sea have the highest salinities on Earth.

What is the Hadalpelagic Zone?

The deepest zone of the ocean, the hadalpelagic zone extends from 19,700 feet (6,000 meters) to the very bottom at 35,797 feet (10,911 meters) in the Mariana Trench off the coast of Japan. The temperature is constant at just above freezing. The weight of all the water over head in the Mariana Trench is over 8 tons per square inch (the weight of 48 Boeing 747 jets).

What is the Bathypelagic Zone?

The depths from 3,300 - 13,100 feet (1,000-4,000 meters) comprise the bathypelagic zone. Due to its constant darkness, this zone is also called the midnight zone. The only light at this depth (and lower) comes from the bioluminescence of the animals themselves. The temperature in the bathypelagic zone, unlike that of the mesopelagic zone, is constant. The temperature never fluctuates far from a chilling 39°F (4°C). The pressure in the bathypelagic zone is extreme and at depths of 13,100 feet (4,000 meters), reaches over 5850 pounds per square inch!

What is a solvent?

The dissolving agent.

What layer does the thermocline often coincide with?

The halocline

The ocean has three primary layers. What are they?

The layers are the surface layer (sometimes referred to as the mixed layer), the thermocline and the deep ocean.

What is a solute?

The materials dissolved.

What is the surface layer sometimes referred to?

The mixed layer.

What is the pycnocline?

The pycnocline encompasses both the halocline (salinity gradients) and the thermocline (temperature gradients), and refers to the rapid change in density with depth.

What is the halocline?

The region where salinity changes sharply with depth.

In temperate zones, the thermocline will be most pronounced during when?

The summer

What is the surface or mixed layer?

The surface layer is the top layer of the water. This layer is also known as the mixed layer and is well stirred from the wind and other forces. This top ocean layer tends to be the warmest layer due to heating from the sun.

About 90% of the Earth's oceans exist below what ocean layer?

The thermocline (and pycnocline)

The ocean layer where temperature changes most rapidly with depth is called?

Thermocline

What is the Principle of Constant Proportions?

This principle states that the ratio of any two major constituents dissolved in seawater is constant. If a scientist can measure one of the major constituents in seawater, he/she can calculate the amounts of all other major constituents and the salinity of the sample.

What is the Epipelagic Zone?

This surface layer is also called the sunlight zone and extends from the surface to 660 feet (200 meters). It is in this zone that most of the visible light exists. With the light comes heating from sun. This heating is responsible for wide change in temperature that occurs in this zone, both in the latitude and each season. The sea surface temperatures range from as high as 97°F (36°C) in the Persian Gulf to 28°F (-2°C) near the north pole. Interaction with the wind keeps this layer mixed and thus allows the heating from the sun to be distributed vertically. At the base of this mixing layer is the beginning of the thermocline. The thermocline is a region where water temperature decreases rapidly with increasing depth and transition layer between the mixed layer at the surface and deeper water.

What percent of seawater is pure water (H2O)?

Typically over 90%.

At the mid-latitudes, high salinity levels can result from what?

Warm, dry conditions and increased evaporation.

Low-density water tends to be what?

Warmer and less saline.

In the polar regions the thermocline is what?

Weak or nonexistent.

Ocean layers affect currents which influence what?

Weather patterns, and movement of materials like nutrients through the ocean.

What does CTD stand for?

conductivity, temperature and depth

What does a CTD measure?

how easily electric currents pass through a sample of seawater (conductivity)

Seawater is w. A mixture x. An ion y. A compound z. An element

w. A mixture

The "Rule of Constant Proportions" w. Allows scientists to determine salinity from the concentration of a single ion in seawater x. Means that salinity is constant throughout the oceans y. Means that salinity and temperature have the same effects on seawater density z. Means that density of seawater is constant

w. Allows scientists to determine salinity from the concentration of a single ion in seawater

Which of the following is the most abundant ion in sea water? w. Chloride x. Calcium y. Potassium z. Sulfate

w. Chloride

A pycnocline refers to a significant change in: w. Density x. Temperature y. Salinity z. Turbidity

w. Density

Which of the following has the highest average salinity? w. Mediterranean Sea x. Atlantic Ocean y. Arctic Ocean z. Gulf of Mexico

w. Mediterranean Sea

Reminder question: When carbon dioxide combines with ocean water, what is produced? w. Calcium carbonate x. Bicarbonate y. Carbonic acid z. Carbonate

x. Bicarbonate

If you consider the ocean to have many different layers of water, where would you expect to find warm water heated by the sun: w. Near the ocean floor x. Near the ocean surface y. In a layer called the thermocline z. Between 500 - 1,000 meters

x. Near the ocean surface

If all else is equal, increasing the salinity of a seawater sample will also increase its: w. Temperature x. Pressure y. Density z. Turbidity

y. Density

Which of the following best describes water beneath the thermocline: w. Highly variable in temperature x. Warmer than most surface waters y. Relatively uniform and cold in temperature z. Variable by latitude

y. Relatively uniform and cold in temperature

Thermoclines are typically not found below this depth regardless of season and latitude: w. 10meters x. 100 meters y. 500 meters z. 1,000 meters

z. 1,000 meters

What percentage of average seawater is pure water? w. 3.5 x. 50 y. 75.5 z. 96.5

z. 96.5

Which of the following represents the ocean layer which has the most rapid change of salinity with depth? w. Salinicline x. Pycnocline y. Thermocline z. Halocline

z. Halocline

Traditionally, salinity has been expressed as...? w. grams per cubic centimeter x. parts per million y. grams z. parts per thousand

z. parts per thousand