Chapter 24

Sara Nicholas presents the case for dam removal by offering a variety of reasons. Which of the following reasons is her primary argument for removing dams?

All dams harm riparian environments.

Which of the following environmental concerns do both essay discuss?

Dams block passage for migratory fish. Submit

The essay in support of dam removal avoids one key environmental benefit touted by dam advocates. If the authors were participating in a debate, how might dam advocates state this benefit?

Dams use a renewable "fuel" (water) to generate clean electricity.

Eutrophic lakes are typically clear, with little algal growth.

False

In the profundal zone of a lake or pond, the rate of photosynthesis exceeds the rate of respiration.

False

Non-flowing water bodies, such as lakes, are referred to as lotic ecosystems.

False

The velocity of water in a stream channel is greater along the margins of the channel than in the center of the channel.

False

Which of the following statements about estuaries is NOT true?

Most estuarine species are pelagic.

__________ aquatic ecosystems are nutrient poor.

Oligotrophic

__________ represent the feeding group of invertebrates found in rivers and streams that feed on coarse particulate organic matter (CPOM).

Shredders

Which of the following statements about changes in flowing-water ecosystems is true?

Shredders become scarce in increasingly higher-order streams.

What is a riffle?

a fast-moving shallow body of water

In lakes and ponds, decomposition occurs primarily in the

benthic zone.

In lakes and ponds, phytoplankton and zooplankton are most abundant in the

limnetic zone.

What is the largest contributor to pelagic biomass in temperate and tropical waters?

nanoplankton

The __________ province of oceans includes waters over the continental shelf.

neritic

Many physical features dictate life in an estuary. The physical feature with the most influence on organismal distribution is

salinity

Which of these is characteristic of the photic zone of a freshwater biome?

the presence of algae

Which of these statements is supported by the pie charts? Select all that apply.

- most of the fresh water on Earth is found in ice caps and glaciers - fresh water makes up a small percentage of all water on Earth

These pie charts show the distribution of Earth's fresh water. What percentage of Earth's fresh water is found in rivers?

0.01%

The resistant bed forces the base level of the stream to be higher than sea level. Since the resistant bed forces the stream to have a more gradual gradient, the strata overlying the resistant bed cannot be completely eroded away. The stream will have a uniform profile only when the resistant bed has eroded away. Rank the labeled locations in the following figure based on stream power. Rank from highest stream power to lowest stream power. To rank items as equivalent, overlap them.

c b a

The term __________ refers to the floor of the sea, while the term benthos refers to __________.

benthic; organisms that live on the ocean floor

What are the pelagic waters of the oceanic zone?

characterized by phytoplankton as the dominant autotrophs and zooplankton as the major herbivores

Ecological communities near deep-sea thermal vents include __________ as primary producers able to use __________ to release energy that can be used to fix carbon.

chemosynthetic bacteria; oxidation of reduced sulfur compounds

The figure below shows a mountain stream that has been dammed. The dam has created an artificial lake into which the mountain stream now flows. Label the diagram to specify which points are below base level, at base level, and above base level for the stream flowing into the artificial lake. Drag the appropriate labels to their respective targets. Labels may be used more than once.

(left to right) A - below ultimate base level B - ultimate base level C - local base level D - above local base level

Aquatic biomes can be distinguished by chemical characteristics such as dissolved oxygen content and salinity and by physical characteristics such as water flow. Which five of the following statements about aquatic biomes are true?

A freshwater organism permanently attached to the substrate would be unlikely to survive and reproduce in an estuary. Estuaries are very productive and are used as breeding grounds by many species of fish. Tropical coral reefs generally exist in relatively shallow areas of the ocean. Temperature drives water movement in some lakes. Wetlands have slow water movement or no water movement and no turnover.

Thomas Flint and Christine Stallard cite multiple benefits of dams. Which of the following statements represents their primary argument for the importance of dams?

Global water use has increased at twice the rate of population growth, and dams can provide water.

Which of the following statements about marine ecosystems is true?

The microbial loop adds trophic levels to the marine food chain.

Match each of the following processes with one of the three zones shown on the figure of a river system. Drag the appropriate labels to their respective targets.

Zone of sediment production (Streams in the mountain) Zone of sediment transportation (River in between the mountain and shore) Zone of sediment deposition (Streams that end at the shore)

In many temperate lakes, thermal energy from sunlight causes changes in the temperature of surface waters. These changes initiate a turnover, a mixing of waters that occurs in spring and fall. Determine the correct order of events involved in seasonal turnover. Drag the labels onto the flowchart of seasonal turnover. Labels may be used once, more than once, or not at all.

a. surface water warms to 4 C and sinks b. water mixes, bringing oxygen to the bottom and nutrients to the surface c. warm surface water is separated from cooler bottom water by thermocline d. surface water cools to 4 C and sinks e. water mixes, bringing oxygen to the bottom and nutrients to the surface

Which of the following statements about coral reef communities is NOT true? a. Most coral colonies live on the skeletons of dead ancestors. b. Reef-building corals are limited to warm tropical waters with high concentrations of carbon dioxide and relatively high salinity. c. The symbiotic relationship between corals and zooxanthellae allows for the formation of large reefs. d. Coral reefs are found in relatively unproductive waters. e. There are three major types of coral reefs: atolls, barrier reefs, and fringing reefs.

b. Reef-building corals are limited to warm tropical waters with high concentrations of carbon dioxide and relatively high salinity.

Which of the following statements about lakes is FALSE? a. Lakes may form from debris blocking a slow-moving stream. b. Some lakes are so large that they mimic marine environments. c. Most ponds and lakes have outlet streams. d. Retreating glaciers form ponds and lakes. e. The formation of ponds and lakes occurs only through geological activity.

e. The formation of ponds and lakes occurs only through geological activity.

A(n) _____ is a region where fresh water and salt water mix.

estuary

In lakes and ponds, photosynthesis occurs primarily in the

limnetic zone. Submit

The _____ biome is the largest of Earth's biomes.

marine

Which of the following bodies of water best represents a lotic ecosystem?

stream

The benthic zone of aquatic environments is defined as the _____.

substrate at the bottom of the body of water

For each factor described below, decide whether dams have an overall positive impact on it, an overall negative impact on it, or both positive and negative impacts on it. Drag each label to the appropriate bin. Dams have an overall positive impact on:

Dams have an overall positive impact on: - electricity generation- supplies of drinking water and irrigation water for nearby cities - reducing property damage from seasonal flooding in downstream areas Dams have an overall negative impact on: - the risk of catastrophic flood damage in downstream areas - supplying sediments to downstream habitats Dams have both positive and negative impacts on: - recreational opportunities - fish populations in the river system

Use what you know about lentic and lotic systems to determine which of the following statements about the regulation of river ecosystems is NOT true.

Flood-control dams only hold a small amount of water and usually allow it to flow in non-flood situations. These types of dams will have a large effect on fish communities.

Analyze the graph and sort the following characteristics as those which appear at the headwaters and mouth of the stream. Drag the appropriate items into their respective bins. Each item may be used only once.

Headwaters -Channel roughness is high -Channel size is smaller Mouth -Slope is lower -Discharge is higher -Flow velocity is more

Based on the characteristics of the sediments, such as size, mass, and solubility, the sediments are classified into dissolved, suspended, and bed loads. Dissolved loads comprise sediments that are very small in size and are carried in solution. Suspended loads are sediments that float in the water since they are neither large/massive enough to settle down on the stream bed nor are soluble enough to dissolve completely. Bed loads are all the coarser sediment that are bigger and heavier in size and shape. The ability of a stream to erode and transport sediments is directly related to its velocity, which is the speed at which water flows through a stream. You will match the influence of velocity associated with each type of load transport. Drag the appropriate labels to their respective targets.

Nature load Dissolved load - unaffected by velocity of stream Suspended load - affected by both flow velocity and setting velocity of stream Bed load - Highly affected by the velocity of stream

Which of the following statements about productivity in oceans is NOT true?

Net primary productivity in the Antarctic is very low due to light and nutrient limitations.

Classify each pollutant in the category that best describes its impact on oceans. Place each label into the appropriate bin.

Nutrient pollution: - Agricultural runoff containing nitrogen and phosphorous fertilizers - Sewage from cities Chemical pollution: - Oil spilled from ocean drilling - Oil and gasoline dripped from motor vehicles - Mercury from power plant emissions Trash and debris pollution: - Garbage from cruise ships - Torn fishing nets - Plastic bottle caps mistaken as food by sea birds

You are part of a panel that reviews dam permits for renewal. Your panel hears testimony from both pro-dam and pro-dam removal advocates. Which of the following scenarios is least likely to be controversial?

Removal of a mill dam for a now defunct mill operation Submit

Stream channels have three major zones, from their headwaters to the mouth, and each zone exhibits unique characteristics. Label the zones of a river system based on the dominant process operating within each zone. Drag the appropriate labels to their respective targets. You may reuse labels.

Zone of sediment production (Streams in the mountain) Zone of sediment transportation (River in between the mountain and shore) Zone of sediment deposition (Streams that end at the shore)

Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Not all terms will be used.

_______ refers to all liquid fresh water located above ground. - surface water Precipitation that infiltrates Earth's surface and percolates downward becomes _______ . - groundwater A_______is a large body of water that has extensive areas of open water, some of which is too deep for photosynthetic life. - lake A_______ meanders across land and structures the landscape. - river A_______is the entire land area that supplies a river or stream with water from precipitation. - watershed A_______has water-saturated soil, shallow standing water, and ample vegetation. - wetland

Zones in lakes and oceans are delineated by depth, distance from shore, or light penetration. Different zones have different physical and chemical characteristics, such as temperature and salinity. Label the diagrams of zonation in lakes and oceans. Drag the labels to their correct targets on the diagrams below.

a.) freshwater plants may be rooted here b.) littoral zone c.) limnetic zone d.) alternately dry and submerged e.) extends to edge of the continental shelf f.) generally low nutrient levels g.) light penetrates here h.) no photosynthesis occurs here i.) benthic zone

The oxygen-minimum layer of an ocean occurs in the

mesopelagic zone.

Deeper, nutrient-rich ocean waters are brought up to the surface by __________.

upwelling

Coral reefs grow best where water is

warm, shallow, and clear.

You are trying to help a friend sort some specimens in her lab. She collected organisms from a lake and forgot to label the sample with the part of the lake from which they were taken. Please select the item below that is correctly matched with its collection zone.

zooplankton labeled "limnetic zone"