Chapter 12

Question 1

Availability of Freshwater

Answer 1

Only 2.5% of Earth’s water is freshwater and only 1% of that is available for humans use in surface water, lakes and soil moisture; the rest is stored in glaciers and ice caps; (Fig 12.2)

Question 2

Distribution in Space and Time

Answer 2

nations vary tremendously in the amount of fresh water per capita available to there citizens; for example Iceland, Papua New Guinea, and Guayana have 100 times more water per person than do many Middle Eastern and North African countries (Fig 12.18)

Question 3

Groundwater

Answer 3

water beneath the surface held within pores in soil or rock

Question 4

Aquifer

Answer 4

porous formations of rock, sand or gravel that hold groundwater

Question 5

Water table

Answer 5

the upper limit of groundwater held in an aquifer; the boundary between an aquifer’s upper layer where pore spaces are partly filled with water and the lower layer where the spaces are completely filled with water

Question 6

Ogallala aquifer

Answer 6

largest known aquifer which is under the Great Plains in the U.S.; used to help farmers create productive grain products; but there are unsustainable water withdrawals that are threatening long-term use of the aquifer for agriculture

Question 7

Tributary

Answer 7

a smaller river flowing into a larger one

Question 8

River system

Answer 8

includes a river source (mountains), tributaries, the main river, floodplain, wetlands, river mouth; ie. watershed

Question 9

Watershed

Answer 9

an area of land drained by a river and all its tributaries

Question 10

Floodplain

Answer 10

areas nearest a river’s course that get flooded periodically

Question 11

Riparian forest

Answer 11

riverside forests that are productive and species-rich; frequent deposition of silt (eroded soil) from flooding makes floodplain soils especially fertile

Question 12

Limnetic zone of a lake

Answer 12

layer of open, sunlit water where photosynthesis takes places; supports phytoplankton which in turn support zooplankton

Question 13

Profundal zone of a lake

Answer 13

deeper part of open water where sunlight does not reach; no phytoplankton and has lower dissolved oxygen than upper parts

Question 14

Benthic zone of a lake

Answer 14

the bottom of the water body; often muddy, rich with detritus and nutrients and low in oxygen; many invertebrates live in the mud feeding on detritus

Question 15

Littoral zone of a lake

Answer 15

around the nurtient rich edges of the water body; shallow water where emergent aquatic plants grow along the shoreline; lots of invertebrates such as insects, larvae, snails and crayfish

Question 16

Oligotrophic lakes

Answer 16

low nutrients and high oxygen

Question 17

Eutrophic lakes

Answer 17

high-nutrient and low oxygen

Question 18

Wetlands

Answer 18

systems in which the soil is saturated with water and which generally features shallow standing water with ample vegetation

Question 19

Marshes

Answer 19

shallow water allows plants such as cattails and bulrushes to grow above the water surface

Question 20

Swamps

Answer 20

also consist of shallow water rich in vegetation but they occur in forested areas

Question 21

Bogs

Answer 21

ponds covered with thick floating mats of vegetation and can represent a stage in aquatic succession

Question 22

Vernal pools

Answer 22

seasonal wetlands that form in early spring from rain and snowmelt and dry up once the weather becomes warmer

Question 23

Consumptive water use

Answer 23

the removal of water from an aquifer of from a body of surface water without returning it

Question 24

Nonconsumptive water use

Answer 24

does not remove or only temporarily removes water from an aquifer or surface water body; example is using water to generate electricity at hydroelectric dams because water is taken in passed through dam machinery in turn turbines and released downstream

Question 25

Salinization

Answer 25

the buildup of salts in surface soil layers

Question 26

Dikes and levees

Answer 26

long raised mounds of earth along riverbanks to hold water in main channels; prevent flooding but can sometimes worsen flooding because they force water to stay in channels and accumulate

Question 27

Dam

Answer 27

any obstruction placed in a river or stream to block its flow

Question 28

Resevoirs

Answer 28

created by dams; artificial lakes that store water for human use

Question 29

Colorado River example

Answer 29

highly diverted and utilized as the river flows to the Pacific Ocean; Denver and Las Vegas uses water from it

Question 30

Desalinization

Answer 30

the removal of salt from seawater by heating it and condensing the water vapor that evaporates; basically distilling fresh water; expensive and requires a lot of fossil fuel energy, kills aquatic life at water intakes and generates concentrated salty waste

Question 31

Agriculture Solutions

Answer 31

flood and furrow irrigation only uses about 40% of water and if extremely wasteful; low-spray irrigation and drip irrigation should be used

Question 32

Household Solutions

Answer 32

installing low-flow faucets, showerheads, washing machines and toilets; catch and store runoff in a barrel for outdoor water use; replacing exotic plants with native ones that are adapted to the climate

Question 33

Industry and municipality solutions

Answer 33

recycling municipal treated wastewater for irrigation and industrial uses; patching leaks in pipes, retrofitting homes with efficient plumbing, auditing industry and promoting conservation

Question 34

Bottled Water

Answer 34

tap water is more regulated by the EPA; half of bottled water IS tap water; people pay thousands of times more for bottled water; tap water is free!; only 30-40% of plastic water bottles actually get recycled; contributes to pollution and wastes energy

Question 35

Point Sources

Answer 35

discrete locations such as factory, sewer pipe or oil tanker; industrial discharges

Question 36

Non-Point Sources

Answer 36

cumulative, arising from multiple inputs over larger areas such as farms, city streets and residential neighborhoods

Question 37

Toxic chemicals

Answer 37

pesticides, petroleum products and other synthetic chemicals made by humans; can poison plants and animals, alter aquatic ecosystems and cause health problems; toxic metals: lead, arsenic, mercury; acid

Question 38

Pathogens and waterborne diseases

Answer 38

pathogenic viruses, protists and bacteria from human or animal waste from feedlots, chicken or hog farms; diseases include cholera, dysentery, typhoid fever

Question 39

Biodegradable wastes

Answer 39

decreases dissolved oxygen levels; human wastes, animal manure, paper pulp from paper mills, yard wastes; wastewater is a source of biodegradable wastes

Question 40

Thermal pollution

Answer 40

raising water temperatures by removing streamside vegetation that shades water from the sun or withdrawing water from a river to cool an industrial facility and transferring the heat back into the river where the water is returned; can cause physiological stress in overheated plants and animals; too little heat can also cause problems: dammed rivers bottoms of reservoirs colder than water at the surface; sudden drop in temp can affect wildlife

Question 41

Distribution of the Oceans

Answer 41

Pacific, Atlantic, Indian, Arctic and Southern

Question 42

Bathymetry

Answer 42

the measurement of depth of water in oceans, seas, or lakes; figure 12.9 continental shelf drops at the shelf-slope break, then steep continental slope gives way to the more gradual continental rise; sea-floor spreading gives way to oceanic ridges and crust; volcanic activity along trenches

Question 43

Composition of Oceans

Answer 43

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Question 44

Vertical Structure of Oceans

Answer 44

Depth zones: mixed, pycnocline and deep

Question 45

Currents

Answer 45

vast riverlike flows that move in the upper 400 m of water, horizontally and for great distances; wind, solar heating, gravity, density differences and the Coriolis Effect drive the global system of ocean currents

Question 46

Thermohaline cycle

Answer 46

worldwide current system; warm surface currents carry heat from equatorial waters northward toward Europe where they warm the atmosphere; the water then cools and sinks forming the North Atlantic Deep Water

Question 47

Upwelling

Answer 47

rising of sea water

Question 48

Downwelling

Answer 48

downward movement of fluid

Question 49

El Nino-Southern Oscillation

Answer 49

an interaction between ocean currents and the atmosphere that influences climate; a systematic shift in atmospheric pressure, sea surface temperature and ocean circulation in the tropical Pacific Ocean; air pressure decreases in the eastern Pacific and increases in the western Pacific, weakening equatorial winds and allowing the warm water to flow eastward; occur every 2 to 8 years

Question 50

Coastal

Answer 50

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Question 51

Benthic

Answer 51

ocean floor

Question 52

Pelagic

Answer 52

habitats and ecosystems occurring between the ocean's surface and floor

Question 53

Photic

Answer 53

well-lit top layer where nearly all of the oceans' NPP occurs; uppermost 10 m (33 ft) absorbs 80% of the solar energy that reaches its surface

Question 54

Dysphotic

Answer 54

barely-lit ocean layer; found just below the photic zone

Question 55

Aphotic

Answer 55

layer of ocean that has no light

Question 56

Open-Ocean

Answer 56

uppermost water contains billions of phtoplankton that is the food base of the marine food chain; also home to zooplankton, small animals, protists that eat phytoplankton and comprise next trophic level (Fig 12.17)

Question 57

Kelp Forests

Answer 57

"forests" of tall brown algae known as kelp that grows from the floor of the continental shelf; numerous fish and other creatures that eat kelp or find refuge among it lives there (Fig 12.15)

Question 58

Coral Reefs

Answer 58

provide food and shelter for a tremendous diversity of fish and other creatures; today reefs face many stresses from human impacts; many corals have died from coral bleaching in which coral lose their zooxanthellae which is evidenced by their whitened coral (Fig 12.16)

Question 59

Intertidal zones

Answer 59

stretches along rocky shorelines between the lowest and highest reached of the tides; provides niches for diversity of organisms: sea stars, crabs, sea anemones, corals, chitons, mussels sea slugs and sea urchins; areas higher on shoreline are exposed to air more frequently so organisms must be able to tolerate that exposure (Fig 12.14)

Question 60

Salt marshes

Answer 60

occur in temperate intertidal zones where the substrate is muddy; tidal waters flow in channels called tidal creeks amid flat areas called benches, sometimes partially submerging the salt-adapted grass (Fig 12.12)

Question 61

Mangrove forests

Answer 61

line tropical and subtropical coastlines; mangrove trees have unique roots and are adapted for growing in saltwater and provide habitat for many fish, birds, crabs and other animals (Fig 12.13)

Question 62

Estuaries

Answer 62

an area where a river flows into the ocean, mixing fresh water with salt water

Question 63

Nets and plastic debris

Answer 63

discarded fishing nest, fishing lines, plastic bags, bottles and other trash harm aquatic organisms; sea birds and other mammels can mistake floating trash for food and die as a result of ingesting the material; chemicals in plastics have toxic effects on organisms; they can also serve as "rafts" that facilitate introduction of invasive species to new habitats

Question 64

Oil spills

Answer 64

Regulations on the oil shipping industry and improved spill response techniques have resulted in less oil being spilled into the oceans today (fig 12.27)

Question 65

Toxins

Answer 65

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Question 66

Excess nutrients

Answer 66

excess nutrients from fertilizers and other chemicals that get into runoff and into oceans have caused areas of low ocean levels; dead zones

Question 67

Sediments

Answer 67

sediments wash into the Pacific Ocean from a river in Panama from farming, construction and other human activities that cause elevated levels of soil to enter waterways which affects water quality and wildlife

Question 68

Acidification

Answer 68

reduction in pH over an extended period of time; caused primarily from the uptake of carbon dioxide from the atmosphere

Question 69

Factory fishing

Answer 69

commercial fishing fleets use several methods of capture (Fig 12.30)

Question 70

Peak yields

Answer 70

Total global fisheries catches rose for many years and now has stalled for the past 20 years; scientists fear global decline is imminent is conservation measures are not taken

Question 71

Driftnetting

Answer 71

long transparent nylon nets are set out to drift through open water to capture schools of fish

Question 72

Longlining

Answer 72

lines with numerous baited hooks are set out in open water

Question 73

Bottom-trawling

Answer 73

weighted nets are dragged along the floor of the continental shelf

Question 74

Bycatch

Answer 74

the capture of nontarget animals; large amount of bycatch results from factory fishing

Question 75

Maximum sustainable yield

Answer 75

the number of fish of a given species that can be harvested without reducing future catches

Question 76

Ecosystem-based management (Marine Protected Areas)

Answer 76

shift focus away from individual species and toawrd viewing marine resources as elements of larger ecological systems; set aside areas of ocean where systems can function without human interference; most MPA's have been established along coastlines

Question 77

Example: St. Lucia's Soufriere

Answer 77

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