Redo: Oceanography test #2

The formation of ___________ is the simplest process for removing dissolved constituents of seawater. It involves partial isolation of a cvoastal sea in an _________ climate.

evaporites. arid

Give the concentration of seawater with a salinity of 34.5 o/oo in the following units: a. percent b. parts per million c. grams per kilogram

a. 3.45 % b. 34,5000 ppm c. 34.5 gm / kg

Water's high _____________________ prevents extreme oceanic temperature variations, in turn affecting temperature ranges on land.

heat capacity

Density is expressed as the ratio of ____________ per unit ____________. Consequently, if volume decreases, then density will __________.

mass, volume. Increase

Which of the components in the equation above are nutrients?

nitrate and phosphate

Average salinity in the open ocean is approximately ____________ o/oo.

35

Minor constituents, which comprise <_____% by weight of the dissolved material in seawater, are generally _________________ properties because their relative abundance is changed through biological and chemical processes.

1, nonconservative

How much heat energy is required to convert 10 grams of ice at 0oC to liquid water?

10 gm X 80 cal / gm = 800 cal

How much heat energy is required to convert 100 grams of liquid water at 100oC to water vapor?

100 gm X 540 cal / gm=54,000 cal or 54 kilocalories

Briefly explain the importance of the following unique properties of water to life on Earth: a. Extremely high heat capacity b. Extremely high latent heat of vaporization c. Extremely effective dissolving ability

1. Melting and boiling points (or temperatures)- H2O melts and boils at an amazingly high temperature for a compound made up of such light elements. The graph shows you the melting and boiling points of water compared to those of some similar compounds that form between hydrogen and the other elements of group VI-A in the periodic table (hydrogen sulfide, hydrogen selenide and hydrogen telluride). Notice how the temperatures of water are way out of line with that which would be predicted by the behavior of the other similar compounds. a. The reason for the high melting and boiling temperatures is the hydrogen bonding between water molecules that causes them to stick together and to resist being pulled apart, which is what happens when ice melts and water boils to become a gas. b. Importance = Without this 'stickiness' water would not be a liquid over much of the surface of the Earth where temperatures are relatively high and we would not have an ocean. 2. Specific Heat or Heat Capacity - The specific heat capacity of a compound is a measure of how difficult it is to get the molecules of the compound to vibrate. Because temperature is just a measure of molecular motion - the more the molecules of a substance vibrate - the higher the temperature of the substance. Because of the hydrogen bonding of water molecules it is very difficult to get them to vibrate compared to the molecules of any other common substance. Water is therefore said to have a high specific heat capacity or specific heat. a. Importance = Since water can absorb a lot of heat with only a small increase in temperature, the temperatures of large standing bodies of water remain relatively constant. This thermal buffering protects life on Earth from otherwise possibly lethal temperature fluctuations. 3. Latent heats of fusion and vaporization - measures how much heat you must add to a substance to melt or vaporize it once you have increased the temperature to its melting or boiling points. The excessive energy needed to melt and boil H2O is due to the H-bonds. a. Importance = Liquid water can absorb a lot of heat at one place on the Earth (such as in the Tropics) when evaporation occurs and then transport this heat somewhere else where the water cools, condenses and releases the stored heat. This means that evaporation dissipates much of the Sun's energy thus moderating and stabilizing Earth's surface temperature without appreciable change in the ocean temperature. This heat storage and transportation also has significant consequences for climates and storms such as hurricanes. 4. Density - because of the unique bonding and structure of the water molecule, solid H2O (ice) is less dense than liquid water. Therefore, when water freezes the ice floats on top of the denser liquid water instead of sinking to the bottom. This is different from most compounds which are denser in the solid state than in the liquid state. a. Importance - Freshwater lakes in mid-latitudes don't freeze solid. Instead ice floats on top and like a blanket, insulates the rest of the lake from the freezing temperatures. This profoundly influences the cycles of organisms living in these lakes. B. Solvent Properties - dipolar liquids like water are excellent solvents for ionic substances such as NaCl. Water is probably the best solvent in nature. That is, it is good at dissolving solids into ions in solution. The dipolar water molecules attach their "positive" or "negative" ends to the oppositely charged ions of solid substances immersed in them and pull ions of the solid into the solution as dissolved ions. Ionic substances are most susceptible to this because they consist of a framework of positively and negatively charged particles. C. Light transmission-Seawater transmits the visible wavelengths of sunlight thus allowing plants to live in seawater. D. Sound transmission - The fact that water transmits sound is important to a few life forms such as whales, dolphins, fish, etc. who use their "sonar" to track prey and/or escape predators.

Why are phosphate concentrations so low in the upper 100 meters?

Because any phosphate released into the water by respiration or delivered to the seawater by river discharge is automatically taken up by nearby plants.

If data for silica were plotted on the diagram, what would the curve look like?

It would show the same shape and depth relationships as the phosphate curve

On the graph draw a line showing the variation of carbon dioxide concentration with depth in the portion of the Atlantic Ocean described above

The CO2 curve will have the same shape as the phosphate curve.

e. What effect should the interplay between photosynthesis and respiration have on the carbon dioxide concentration of the seawater?

The carbon dioxide concentration should be lowest where photosynthesis is actively occurring (i.e., above 100 meters) and should increase below that depth, where it is released during respiration.

The ____________ is a unit of heat measure that refers to the amount of heat required to raise the temperature of _____g. of liquid water by ______ degree C.

calorie, one, one

The ___________ is a unit of temperature measurement.

degree centigrade (C)

As the salinity of seawater increases, its density ___________.

increase

As the pressure on seawater increases, its density ___________.

increases

What components in the above equation are produced during the photosynthesis reaction?

organic matter and oxygen

The volatile constituents of Earth's ocean and atmosphere gradually formed from____________ activity, followed by interaction between water and rocks, called _______________ ,to dissolve the non-volatile constituents and add them to the seawater.

volcanic, weathering

Using the data from the graph above, in what portion of the ocean does photosynthesis exceed respiration?

Photosynthesis exceeds respiration to about 100m.

The most complicated gas in seawater is __________. In the _________ cycle, it forms a buffer which acts to stabilize the acidity of seawater.

carbon dioxide, carbonate / carbon dioxide

What components in the equation are consumed during the photosynthesis reaction?

carbon dioxide, water, nitrate, phosphate, and hydrogen ion

The ability of water to conduct electricity, termed its ___________, increases with increasing ionic concentration, hence it can be used as a measure of _______________.

conductivity, salinity

A property that remains relatively unchanged in the open ocean is termed _________________. It can be used to trace the movement of water masses in the ocean.

conservative

As the temperature of seawater increases, its density __________.

decrease

The reason why temperature remains constant at the melting point or the boiling point of water is because all heat energy is put into breaking ________________________. This type of energy is called _________ heat.

hydrogen bonds, latent

The movement of all free water on Earth's surface, inlcuding oceans, rivers, lakes, groundwater and atmospheric water is described by the ________________ cycle.

hydrologic

The amount of salt, in grams, dissolved in one ____________ of seawater is called ____________. It is expressed in parts per _________________.

kilogram, salinity, thousands

The relative concentration of H+ is expressed using a ______ scale. The concentration of H+ in the ocean expressed on this scale is __________.

pH, 8.1

The time required to completely replace the amount of a substance in the ocean is called its ____________ time.

residence

The major reservoirs for the major dissolved constituents of seawater are ____________, ____________, and ____________. The major agents for transporting these dissolved constituents into the oceans are the _____________. Important processes involved in the cycles of these constituents include ____________, ____________, ___________, ______________, and_______________. What additional types of processes are important in the cycles of the nutrients?

rocks on the continents, sediments in the oceans, seawater. rivers. evaporation, precipitation, sea spray, hydrothermal reactions at mid-ocean ridges, & river discharge. biological