Life in Water - Chapter 03

A comprehensive set of Q&A flashcards covering transitional environments (salt marshes, mangrove forests, estuaries), rivers and streams, lakes, and human influences based on CH 03 Life in Water.

Where are salt marshes and mangrove forests concentrated?

Along low-lying coasts with sandy shores.

Where are freshwater wetlands located?

In low-lying areas and are inundated with water.

Where are estuaries found?

Where rivers meet the sea.

What is a characteristic of estuarine salinity stratification?

Low-density freshwater on top of higher-salinity bottom water, isolating bottom water from the atmosphere.

What does Salt Marshes describe as the transition between?

The transition between land and sea.

What are tidal creeks in salt marshes?

Channels that fill and empty with the tides.

Name grasses and plants that dominate salt marshes.

Spartina spp., Distichlis spp., pickleweed Salicornia spp., and rushes Juncus spp.

What habitat feature do mangrove prop roots provide?

A complex habitat for a high diversity of marine fish and invertebrates.

How are mangrove tree species distributed within the intertidal zone?

By height, with different species distributed according to height.

What is true about species composition within a region for mangroves?

There is great uniformity in species composition within a region, though it varies between regions.

Why are estuaries, salt marshes, and mangrove forests vulnerable?

Because of highly variable physical and chemical conditions and human interference along the coast.

Why are rivers and streams important?

They drain most of the landscapes of the world and are important to human history and economy.

What are Pools, Runs, and Riffles in rivers?

Pools: deep, slow-flowing areas; Runs: intermediate fast, smoother; Riffles: shallow, fast, turbulent.

What is wetted width versus active channel width?

Wetted width is the water surface width at a moment; Active channel width is the width between permanent banks where water flows.

What is the difference between the water surface and the water column?

Water surface is the uppermost layer; the water column is the entire volume from surface to riverbed.

Do river organisms change from headwaters to mouth?

Yes, the organisms change from headwaters to mouth.

What are the key physical conditions affecting rivers and streams?

Light, water movements (erosion and suspended sediments), and temperature.

What are the chemical conditions in rivers regarding salinity and oxygen?

Salinity; oxygen is inversely related to temperature and is usually not limiting in river systems.

Approximately how many fish species inhabit the temperate Mississippi River basin?

About 300 species.

How many fish species are in the tropical Congo River basin (approximate)?

About 669 species (over 558 endemic).

How many fish species are in the Amazon River?

Over 2,000 species (about 10% of known fish species).

What are common human influences on rivers and streams?

Commerce, transportation, irrigation, waste disposal, and reservoir construction.

What percentage of suitable rivers in the U.S. have dams and reservoirs?

About 98%.

What dam is associated with Lake Nasser?

Aswan High Dam.

What are lakes and how are they formed?

Topographic depressions that collect water; formed by tectonics, volcanism, and glacial activity.

What share of the world’s freshwater is contained in the Great Lakes?

About 20%.

What does eutrophic mean?

High biological production but may be depleted of oxygen.

What are common human influences on lakes?

Municipal and agricultural runoff; exotic species such as Zebra Mussels.

What primarily drives water cycling and movement on a global scale?

Solar energy.

Where are kelp forests and coral reefs distributed?

Kelp forests mainly at temperate latitudes; coral reefs limited to the tropics and subtropics between 30° N and S.

Which environments occur at transitions between freshwater and marine and between marine and terrestrial?

Salt marshes, mangrove forests, freshwater wetlands, and estuaries.

Why are rivers dynamic in relation to land use?

They reflect land use in their basins.

What is a key takeaway about the water systems summarized in this chapter?

Water cycling and movement are driven by solar energy; aquatic biology relates to physical and chemical factors; human impacts threaten these systems.