Estuary Quiz Questions And Answers

1.

What is an estuary?

A.

The land area that drains water into a lake, river, or pond.
B.

The area where a river meets the ocean, where fresh and saltwater mix.
C.

The large body of saltwater that covers most of the earth's surface.
D.

The underground system that provides drinking water to an area.

Correct Answer
B. The area where a river meets the ocean, where fresh and saltwater mix.

Explanation
An estuary is an area where a river meets the ocean, creating a transition zone where fresh and saltwater mix. It is characterized by brackish water, which is a mixture of freshwater and seawater. Estuaries are highly productive ecosystems that support a diverse range of plant and animal species. They also serve as important nurseries for many marine organisms and provide valuable habitats for migratory birds.

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2.

Estuaries have also been called:

A.

Bays
B.

Lagoons
C.

Sounds
D.

Sloughs
E.

All of the Above

Correct Answer
E. All of the Above

Explanation
Estuaries are coastal areas where freshwater from rivers and streams mixes with saltwater from the ocean. They can take various forms depending on the region, and different terms are used to describe them. Estuaries can be referred to as bays, lagoons, sounds, or sloughs, depending on their specific characteristics. Therefore, the correct answer is "All of the Above" as all of these terms can be used interchangeably to describe estuaries.

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3.

Why are estuaries important to our environment?

A.

They provide homes for many species of wildlife.
B.

They are important nursery areas for a variety of marine life.
C.

They help to filter pollutants from the water.
D.

All of the above
E.

A and B

Correct Answer
D. All of the above

Explanation
Estuaries are vitally important to our environment for several reasons. Firstly, they function as diverse ecosystems, providing homes for a multitude of wildlife species. Their unique blend of fresh river water and saltwater creates various habitats, including marshes and tidal creeks, which offer shelter, breeding grounds, and food sources for countless plants and animals. Secondly, estuaries serve as crucial nursery areas for marine life, offering an optimal environment for the growth and development of young fish, crustaceans, and other aquatic organisms. Lastly, estuaries act as natural filters, purifying water by trapping and removing pollutants before they reach the open sea. This capacity to cleanse water plays a pivotal role in maintaining water quality and the health of surrounding ecosystems, making estuaries indispensable components of our environmental landscape.

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4.

The high productivity of estuaries has been attributed to the presence of several primary production units. Which of the following would NOT be considered a primary production unit in an estuary ecosystem?

A.

Phytoplankton suspended within the sunlight zone of the water column.
B.

Benthic algae and microscopic plants that live on the sediment surface wherever sunlight reaches the bottom.
C.

Macroflora, such as marsh grasses which are the foundation of many food webs and provide nursery grounds for most coastal shellfish and finfish.
D.

Juvenile zooplankton brought to the estuary by tides after hatching offshore.
E.

B and D

Correct Answer
B. Benthic algae and microscopic plants that live on the sediment surface wherever sunlight reaches the bottom.

Explanation
The correct answer is Benthic algae and microscopic plants that live on the sediment surface wherever sunlight reaches the bottom. This option would NOT be considered a primary production unit in an estuary ecosystem because primary production in estuaries primarily occurs in the water column, where sunlight is available for photosynthesis. Benthic algae and microscopic plants on the sediment surface rely on sunlight reaching the bottom, which is not as efficient for primary production as phytoplankton suspended in the water column.

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5.

What percent of the ocean is salinity?

A.

3.5
B.

10.5
C.

50
D.

70

Correct Answer
A. 3.5

Explanation
The answer is 3.5 because salinity is typically measured in parts per thousand (ppt) or as a percentage. The average salinity of the ocean is about 35 ppt or 3.5%. This means that for every 1000 parts of water, there are 35 parts of dissolved salts. Therefore, 3.5% of the ocean is salinity.

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6.

The place where two oceans meet is also called an estuary.

A.

True
B.

False

Correct Answer
B. False

Explanation
An estuary is not the place where two oceans meet. An estuary is a partially enclosed coastal body of brackish water, formed where freshwater from rivers and streams mixes with saltwater from the ocean. When two oceans meet, it is called an oceanic convergence or a confluence, not an estuary. Therefore, the correct answer is false.

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7.

Lawrence River is the largest estuary.

A.

True
B.

False

Correct Answer
A. True

Explanation
The statement is true because the Lawrence River is indeed the largest estuary. An estuary is a partially enclosed coastal body of water where freshwater from rivers and streams mixes with saltwater from the ocean. The Lawrence River, located in Canada, is the largest estuary in the world by discharge volume. It is formed by the confluence of several rivers and is known for its rich biodiversity and important role in the ecosystem.

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8.

Water is brought to an estuary from a variety of sources. Which of the following is responsible for increasing the salinity in the estuary?

A.

Rivers
B.

Streams
C.

Urban runoff
D.

Tides
E.

All of the above

Correct Answer
D. Tides

Explanation
Tides are responsible for increasing the salinity in the estuary. Tides bring in seawater from the ocean, which has a higher salinity compared to freshwater sources like rivers, streams, and urban runoff. As the tides come in, they mix with the freshwater sources, resulting in an increase in salinity in the estuary. Therefore, all of the above options contribute to the increase in salinity in the estuary.

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9.

Many shorebirds feed on the mudflats of estuaries. When would be the best time for the birds to catch stranded fish and invertebrates?

A.

During tidal ebb
B.

During tidal flow
C.

A and B
D.

Birds don't eat mud
E.

All of the above

Correct Answer
B. During tidal flow

Explanation
During tidal flow, the water level is rising, which allows the birds to access the fish and invertebrates that are brought in with the incoming tide. This is the best time for the birds to catch their prey as it is being carried towards them by the moving water. During tidal ebb, when the water level is falling, the prey may be carried away from the birds, making it less favorable for feeding.

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10.

Water in most estuaries is brackish because of the mixing of freshwater from rivers and saltwater from incoming tides. A drought in the bay watershed would most likely cause the water in the bay to…

A.

Increase in salinity
B.

Decrease in salinity
C.

Stay the same
D.

Rise
E.

A ,B, and C

Correct Answer
D. Rise

Explanation
A drought in the bay watershed would most likely cause the water in the bay to rise. During a drought, there is a decrease in freshwater flow from rivers into the bay, while the saltwater from incoming tides remains constant. This imbalance between freshwater and saltwater would cause the salinity of the bay water to increase, leading to a rise in salinity.

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