World Oceans Test 2 Part 3

In which of the following settings would anoxic conditions be likely to occur? Hint: Recall that anoxic means lacking in dissolved oxygen. (Select all that apply.)

-Isolated, deep basins -Bottom of an ocean trench

Choose the three major sources of carbon dioxide in the oceans

-Oxidation of organic matter -Transfer from the atmosphere -Respiration of marine organisms

The major ionic constituents of sea salt are normally found to _______

-have a constant ratio of each constituent to each other -behave as conservative materials -have the same ratio to each other even when diluted by rainwater

Which of the following are the six major constituents of seawater?

-sodium -sulfate -magnesium -potassium -chloride -calcium

Describe how a solar still works to desalinate seawater by putting the steps in the right order, with the first step on top.

1. a pool of sea water is capped with a plastic dome 2. solar radiation evaporates the seawater 3. evaporated water condenses on the dome and trickles down the sides where it is connected

arrange the following seawater constituents from longest residence time to shortest

1. chloride 2. sodium 3. calcium 4. water 5. iron

Rank the major constituents of seawater according to their abundance by weight, with the highest weight at the top and the lowest weight at the bottom.

1. chloride 2. sodium 3. sulfate 4. magnesium 5. calcium 6. potassium

carbon dioxide species sequence

1. gaseous CO2 2. dissolved CO2 3. carbonic acid 4. bicarbonate 5. carbonate

arrange each gas in order from largest percentage by volume to smallest in the atmosphere

1. nitrogen 2. oxygen 3. carbon dioxide

Rank the following substances according to pH, with the most acidic on top.

1. sulfuric acid 2. soda 3. milk 4. pure water 5. bleach

About ______ percent of the weight of seawater is dissolved salts

3.5

What is the average pH of seawater?

7.8

How is the abundance of major seawater constituents related to solubility and residence time?

Abundant constituents are soluble and have a high residence time

Electrodialysis

An electrical field is used to transport ions out of solution and through a semipermeable membrane

How is reverse osmosis employed to desalinate seawater?

Applied pressure forces water molecules through a semipermeable membrane; salts cannot fit through the membrane and are left behind.

In warm climates, salt in seawater is concentrated using evaporation and then extracted for use. How is salt recovered in cold climates?

By allowing the water to freeze and then collecting the leftover brine

Ocean acidification primarily is the result of the increase of ______ concentrations in the atmosphere.

CO2

True or false: Trace elements are labeled as such because they are unimportant to ocean processes.

FALSE

Which of the following are involved in using reverse osmosis to desalinate water?

FORCED PRESSURE AND SEMIPERMEABLE MEMBRANE

Which of the following statements best describes the seasonal changes in ocean water salinities of polar areas?

Ice forming in the winter increases salinity, and ice melting in the summer decreases salinity

What happens to the approximately 300 million metric tons of excess oxygen produced each year by photosynthetic marine organisms?

It is incorporated into sediments and then eventually formed into rocks

Why does ocean salinity change with latitude?

Latitude influences evaporation and precipitation within the hydrologic cycle

Choose the advantages (over the disadvantages) of using reverse osmosis to desalinate seawater.

No thermal pollution Heating of water is not required Removal of contaminants

ion exchange

Resins are used in a column of water to extract unwanted ions.

The oceans are a major contributor of oxygen to the earth's atmosphere

TRUE

surface water

The pH is high (alkaline) due to low concentrations of CO2.

deep water

The pH is low (acidic) due to high concentrations of CO2.

What happens to the organic substances present in seawater

They are used by organisms. They are broken down into smaller particles. They accumulate in sediments.

Which of the phrases does not correctly describe compensation depth?

This depth is permanently at 200 meters below the surface

How do changes in CO2 concentration in seawater affect pH?

When CO2 increases, then pH decreases

You use a salinometer to measure the salinity of two water samples, and the results show that Sample A has a higher conductivity than Sample B. Can you assume that Sample A has a higher salinity?

Yes, because the more ions in the form of dissolved salts available, the more conductive the liquid

pH less than 7

acidic

Respiration by ________ is the most important process in the removal of oxygen from seawater in the deep ocean

bacteria

pH greater than 7

basic

The process by which CO2 (and then carbon) is added to intermediate and deep-ocean water and the ocean bottom, through the involvement of photosynthetic organisms, is called the ______

biological pump

Water solutions contain ______

both H2O molecules and H+ and OH- ions

A substance that acts to prevent the sudden change of pH in a solution is called a

buffer

By measuring the pH of seawater, one can indirectly determine the water's ______ concentration

carbon dioxide

Which two of the following gases are the most important for biological activity in the oceans?

carbon dioxide and oxygen

Salinity may be measured by checking the water's _______

conductivity

Increased CO2 concentrations in seawater result in a

decrease in pH

In general, oxygen content ______ with water depth in the ocean

decreases

What is the general name of the process used to obtain fresh water from salt water?

desalination

Nutrients are nonconservative constituents of seawater because they _______

do not maintain constant ratios to each other and are recycled into plants and animals

The cations found in seawater originally came from ______, whereas the anions originated from ______

earth's crust; earth's mantle

Marine plants undergo photosynthesis in the lighted portion of the ocean called the ______ zone

euphotic

What process is used to concentrate the salt content of seawater in order to extract halite for use as table salt?

evaporation in shallow ponds

The increase in atmospheric CO2 concentrations has resulted in ______ of dissolved CO2 concentrations in seawater

increase

_____ bonds, those formed due to the attraction of oppositely charged particles, are easily broken in water due to the polar nature of the water molecule.

ionic

The Redfield ratio ______

is related to the average composition of all plankton in the ocean

Ocean salinity changes with ______, as rates of precipitation, evaporation, and runoff are strong influences on how much salt is dissolved in ocean water.

latitude

Methods of desalination that work particularly well with ______ water include ion exchange resins and electrodialysis

low-salinity

pH equal to 7

neutral

The Redfield ratio is the relative molar abundance of carbon ________ and phosphorus in marine phytoplankton, and is 106:16:1

nitrogen

Areas such as Saudi Arabia and Kuwait that have little fresh water can afford desalination because they have an enormous amount of readily available _____ resources

oil

In the deep ocean, bacterial respiration is the most important factor in the removal of ______ from seawater

oxygen

Marine plants undergoing photosynthesis produce and release ______ into seawater

oxygen

The most abundant dissolved gases present in the ocean are

oxygen, nitrogen, and carbon dioxide

Nitrogen, __________ and silicate are important to different forms of marine life for growth, as they act like the fertilizers of the ocean. These ions are present in very low concentrations in seawater

phosphorus

Carbon dioxide concentrations are low in the ocean's surface waters because it is used in

photosynthesis

Marine plants take up carbon dioxide from seawater in order to

photosynthesize

The relative ______ of major seawater constituents remain the same for different geographic locations and water depths

ratios

The relative ratios of major seawater constituents _____

remain the same, regardless of depth or geographic location

The average time a substance remains in the ocean (or any specific part of the hydrologic cycle) is called its

residence time

The ______ of the oceans has remained relatively constant over time because the input of salts is equal to the output

salinity

Sea spray that is blown ashore, precipitation in the formation of insoluble deposits on the sea floor, and biological processes are all ways in which _______ is removed from the oceans

salt

Adsorption is the most significant process in removing ______ from seawater. Other processes include evaporation, sea spray, biological uptake, and chemical precipitation.

salt ions

Volcanism and land runoff provide the ________ now found dissolved in ocean water

salts

The concentration of CO2 in the atmosphere has increased over the last 150 years primarily due to ______

the burning of fossil fuels and deforestation

The concentrations of nutrient ions in seawater are nonconservative, and they vary because ______

they are closely related to the life cycles of marine organism

How are the concentrations of H+ and OH- ions in a water solution related to each other

they are inversely proportional