I. Cycling (Chap 37.18-21)A. Circular flow of nutrients, carbon, and water

B. Water cycle (34.17)1. environmental

evaporation water vapor rain

2. organismala. root uptakeb. transpiration (evaporation from leaves)

- increased by sun and windc. responsible for some rain in dense forest ecosystems

3. ground water- aquifers- difficult to clean up

C. Carbon cycle (CO2)1. photosynthesis

- use C in CO2 to build organic molecules2. cellular respiration

- get energy by stripping C off of organic molecules- CO2 returned to the atmosphere

3. combustion- wood- fossil fuels

C. Nitrogen cycle1. abundant in atmosphere as N2

- must be “fixed” to NO3- or NH4

+

- nitrogen-fixing soil bacteria

2. fertilizers- manufactured types often exceed soil capacity- potentially dangerous runoff

E. Phosphorus cycle1. need P for

ATP, nucleic acids, phospholipids, bones2. CaHPO4 in rocks and soil PO4

3- in water - taken up by producers

3. phosphate ion levels usually low in fresh water- impacted by sewage, fertilizer, and pesticides

4. phosphate overgrowth of producersa. overgrown organisms dieb. decomposers then overgrow and use up the O2c. eutrophication

II. Weather Effects on Ecosystems (Chap 34.5)

II. Weather Effects on Ecosystems (Chap 34.5)A. Latitudes and rainfall

1. six air masses- cool air holds less water vapor

2. air rises from equator and moves toward polesa. warm air loses water on the way up as it coolsb. cool air comes down, warms up, and soaks up water vapor

3. alternates every 30˚ of latitude

B. Ocean currents- combination of prevailing winds, planet rotation, and solar heating

C. Elevation effects- decrease of around 6˚C for every 1,000 meter increase- can mimic effect of moving north or south from equator

D. Rain shadow1. air cooled as it is forced to rise with a mountain2. ability to hold water vapor is decreased

- results in precipitation3. leeward side of mountain receives air devoid of moisture

- Death Valley

III. Ocean Ecosystems (Chapter 34.6)A. Shallow waters

1. small part of the ocean2. large number of species3. includes intertidal region

4. estuariesa. partly enclosed

- river mouths, coastal baysb. intermediate salinityc. very fertile

5. wetlands- transition between aquatic and terrestrial ecosystems

B. Open ocean surface (pelagic zone)1. most light is in first 100 meters (photic zone)2. phytoplankton

a. microscopic algaeb. cyanobacteriac. around 40% of earth’s photosynthesis

C. Sea floor (benthic zone)1. not enough light for photosynthesis (aphotic zone)2. many feed on organic “debris”3. some are bioluminescent

- communication- attract prey

4. hydrothermal vent communities

IV. Freshwater ecosystems (Chap 34.7)A. Strong link to surrounding landB. Depth zoning similar to oceans

- photic and aphotic zones

C. Overturns- water is most dense at 4˚C