Oceanography Chapter 5
By measuring the pH of seawater, one can indirectly determine the water's ______ concentration.
carbon dioxide
An ion with a positive charge is called a ____.
cation
The ____ zone is shallow in coastal waters but may extend to 200 meters in the open ocean where there are fewer suspended particles and sunlight can reach greater depths.
euphotic
In order for the salinity of the oceans to have remained the same over the past 1.5 billion years, the input of salts into the ocean needs to equal ______.
the output
Ionic bonds are easily broken in ____ because of the polar nature of the ____ molecule.
water; water.
What is the term used to describe the maximum amount of gas that can be held in solution?
Saturation concentration
How does water pouring out from underwater hydrothermal vents affect the salinity of seawater?
The outgoing water has a much higher salinity than the surrounding ocean water.
Which of the following geographic locations are known for their high ocean salinities resulting from both high evaporation rates and low freshwater input? (3 answers)
-Red Sea -Persian Gulf -Mediterranean Sea
The ratios of certain major constituents in seawater do not change and are called ___, while the ratios of constituents present in smaller amounts do change and are known as ___.
-conservative -nonconservative
Rank the residence times of these constituents with the highest at the top of the list.
1. Chloride 2. Potassium 3. Carbonate 4. Iron
Rank 6 major constituents of seawater according to their abundance by weight.
1. Chloride 2. Sodium 3. Sulfate 4. Magnesium 5. Calcium 6. Potassium
In major ocean basins ____ of the weight of seawater is, on the average, dissolved salt and ____ is water.
3.5%; 96.5%
What is a buffer?
A substance that prevents drastic changes in the pH of a solution
How is the abundance of major seawater constituents related to solubility and residence time?
Abundant constituents are soluble and have a high residence time.
What is the most important process for removing elements from seawater?
Adsorption
A way in which salt ions are removed from seawater to its description. -biological uptake
Animals intake seawater and incorporate the calcium and/or silica into their hard parts.
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
Describe what happens when carbon dioxide dissolves in seawater by putting the steps below in the correct order, starting with dissolution on top.
Cabron dioxide; CO2 combines; H2CO3 dissociates.
Rank the gases present in the ocean according to their abundance (percent by volume), with the most abundant on top.
Carbon Dioxide Nitrogen Oxygen
The cations found in seawater originally came from ______, whereas the anions originated from ______.
Earth's crust; Earth's mantle
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? (Choose all that apply.
Forced pressure 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.
A way in which salt ions are removed from seawater to its description. -adsorption
Ions bind to clay particles, sink in the water column and are incorporated into sediments.
A way in which salt ions are removed from seawater to its description. -chemical precipitaion
Ions react with each other to form insoluble products.
How does the formation of new ocean crust at ridge systems affect the salt content of seawater?
It both adds and removes salts from seawater.
Which of the following correctly describe the pH scale? (Select all that apply.)
It ranges from 0 to 14. A pH above 7 represents an alkaline solution. It is a logarithmic scale.
Why does ocean salinity change with latitude?
Latitude influences evaporation and precipitation within the hydrologic cycle.
Select the three important nutrients needed for the growth of marine life (i.e., plants, phytoplankton, and diatoms).
Nitrogen Phosphorus Silicate
Choose the three major sources of carbon dioxide in the oceans.
Oxidation of organic matter Respiration of marine organisms Transfer from the atmosphere
A way in which salt ions are removed from seawater to its description. -isolation
Seawater bodies are cutoff and evaporation leaves behind the salts.
A way in which salt ions are removed from seawater to its description. -sea spray
Seawater is blown onto land, taking along and depositing the salts.
Rank the following substances according to pH, with the most acidic on top.
Sulfuric Acid Soda Pop Milk Pure Water Bleach
Although oxygen content generally decreases with increasing depth in the ocean, a noticeable reverse in the trend occurs around 800 meters. Why?
There is a significant drop in the number of animals that are using oxygen.
What happens to the organic substances present in seawater? (Choose all that apply.)
They are broken down into smaller particles. They accumulate in sediments. They are used by organisms.
How are the concentrations of H+ and OH- ions in a water solution related to each other?
They are inversely proportional.
What are the two primary current sources for the salts in ocean water?
Volcanism Runoff from the land
How do water molecules keep dissolved ions from combining into molecules?
Water molecules are polar and are able to surround ions, preventing them from joining with other ions.
The concentration in dissolved constituents in seawater can be expressed by:
Weight; By Volume; or In molar terms
How do changes in CO2 concentration in seawater affect pH?
When CO2 increases, then pH decreases.
Rates of evaporation are high ______, so salinity is also high.
along the equator
An atom with a negative charge is an ____.
anion
Water coming out of hydrothermal vents on the sea floor has a much ______ salinity than the water that enters the system. Scientists ______ how this affects ocean salinity overall.
higher; do not understand
A negatively charged chloride atom dissolved in water will be surrounded with the positively charged ______ atoms of the water molecule, which prevents the chloride atom from combining with other ions.
hydrogen
A charged atom or group of atoms is call an ____.
ion
Sodium chloride is held together by ____.
ionic bonds
Ocean salinity changes with ___, as rates of precipitation, evaporation, and runoff are strong influences on how much salt is within ocean water.
latitude
If seawater becomes too acidic, the reaction moves to the ______, removing free hydrogen ions from the water.
left
Iron is not abundant in seawater and has a low solubility; correspondingly, it has a ___ residence time
low.
The ______ present in seawater include proteins, carbohydrates, and fats.
organics
Marine plants undergoing photosynthesis produce and release ______ into seawater.
oxygen
The most abundant dissolved gases present in the ocean are ____, ____, and carbon dioxide.
oxygen; nitrogen
Trace elements in seawater are present at concentrations that are measured in ______.
parts per million or less
The ocean contains an average of 35 parts per thousand dissolved salt; this is the ocean's ______.
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 ocean.
salt
Two atoms held together by ionic bonding do so through ______.
the attraction of opposite charges
