Chap. 52 (3)

Question 1

Temperate lakes vs lowland lakes thermocline

Answer 1

Temperate lakes may have a seasonal thermocline; tropical lowland lakes have a year-round thermocline

Question 2

lake animals

Answer 2

• Phytoplankton (algae and cyanobacteria) are found here and carry out photosynthesis
• Zooplankton, consume these phytoplankton
• Invertebrates live in the benthic zone
• Fishes live in all zones with sufficient oxygen
• Human-induced nutrient enrichment can lead to algal blooms, oxygen depletion, and fish kills

Question 3

Wetlands

Answer 3

Wetlands are inundated by water at least some of the time and support
plants adapted to water-saturated soil
* Rapid organic production and decomposition periodically deplete dissolved oxygen
* Wetlands develop in shallow basins, along flooded river banks, or on the coasts of large lakes and seas

Question 4

wetland function and destruction

Answer 4

Humans have destroyed up to 90% of wetlands in Europe; wetlands purify
water and reduce flooding

Question 5

streams and rivers

Answer 5

Headwaters are generally cold, clear, turbulent, swift, and oxygen-rich; they are often narrow and rocky
* Downstream waters form rivers and are generally warmer, more turbid,
and well oxygenated; they are often wide and meandering and have silty
bottoms

Question 6

estuary

Answer 6

• is a transition area between river and sea
• are nutrient-rich and highly productive
• Saltmarsh grasses and algae are the major producers

Question 7

An intertidal zone is

Answer 7

• periodically submerged and exposed by the tides
• Intertidal organisms are challenged by variations in temperature and salinity and by the mechanical forces of wave action
• Oxygen and nutrient levels are high

Question 8

oceanic pelagic zone is

Answer 8

• constantly mixed by wind-driven oceanic
  currents
• Oxygen levels are generally high
• This biome covers approximately 70% of Earth’s surface
• Phytoplankton and zooplankton are the dominant organisms
• Phytoplankton in this zone account for about half of the photosynthesis on Earth
• Fish, squid, turtles, and marine mammals also occupy the pelagic zone

Question 9

Coral reefs

Answer 9

Coral reefs are formed from the calcium carbonate skeletons of corals (cnidarians)
* Shallow reef-building corals live in the photic zone in warm (about 20–30ºC), clear water; deep-sea corals live at depths of 200–1,500 m
* Corals require high oxygen concentrations and a solid substrate for attachment
- Corals form a mutualistic relationship with unicellular algae, which provide
them with organic molecules

Question 10

threats to coral reef ecosystems

Answer 10

Collection of coral skeletons, overfishing, global warming, pollution, and aquaculture are threats to coral reef ecosystems

Question 11

marine benthic zone

Answer 11

• the marine benthic zone consists of the seafloor below the surface
  waters of the coastal, or neritic, zone and the offshore pelagic zone
  -

Question 12

hydrothermal vents

Answer 12

of volcanic origin on mid-oceanic ridges are surrounded by unique chemoautotrophic prokaryotes, as well as echinoderms and arthropods