QUESTIONS AND ANSWERS SURE A+
✔✔Phosphorus cycle - ✔✔terrestrial & aquatic system
-needed for bones, scales, teeth, DNA, RNA, ATP, phospholipids in the cell membrane
✔✔Terrestrial system - ✔✔-PO4 sources: uplifted rock is
weathered/mined, particles
travel in run-off
-plants assimilate PO4 (pass to consumers)
-excretion and decomposition return PO4 to soil
-Leaching/run-off carries "excess" to aquatic system
✔✔Aquatic system - ✔✔-PO4 assimilated by producers (& consumed)
(excreted/decomposed)
-PO4 precipitates and forms sediment
-some sedimentary rock is later uplifted, moving PO$ back to terrestrial system
✔✔Oligotrophic - ✔✔-low nutrient levels (N & P)
-low NPP
-healthy, diverse fish & invertebrate communities
✔✔Eutrophic - ✔✔-nutrient rich (N & P)
, -high phytoplankton, algae abundance and turnover
-oxygen depleted -> anaerobic organisms
-accumulation of detritus, turbid water
-loss of diversity
✔✔Carbon (C) cycle basics: biotic - ✔✔Producers assimilate C via photosynthesis −
CO2 carbohydrates proteins, fats etc. − Pass through consumers and decomposers •
Organisms respire releasing CO2 to environment − Anaerobic respiration (in swamp
and marsh sediments) also produces CH4
✔✔Carbon (C) cycle basics: abiotic - ✔✔Aquatic: CO2 diffuses in and out and CaCO3
precipitates sedimentation slowly creates dolomite and limestone Carbon (C) cycle
basics: abiotic • Aquatic and terrestrial: organic C buried, slowly =fossil fuels
Weathering and eruptions release geological C slowly
Combustion releases C. Some natural.
Fossil fuels extraction and combustion releases CO2 quickly =Recent addition!
✔✔Carbon sinks - ✔✔absorb more carbon than they release
Oceans: have absorbed ~30% of carbon
Land and vegetation: have absorbed ~30% - Vegetation (Forests) - Soils (including,
until recently, peat in permafrost)
Remaining ~40% has gone in the atmosphere
14% of carbon stored in the tundra's permafrost, but it is thawing and has become a
carbon source
Ability of "sinks" to absorb carbon being altered by climate change
✔✔Premature extinction (causes) - ✔✔HIPPO
Habitat destruction, degradation & fragmentation
Invasive species
Population growth
Pollution
Overexploitation
✔✔Habitat loss - ✔✔-urban & suburban development
-expansion of agriculture
-industrial developing, mining
-wetland drainage
-river dams
✔✔deforestation - ✔✔Forests cover 31% of global land area
46-58 thousand miles2 lost each year
Fires, clear-cutting, ranching, development, unsustainable logging, climate change
✔✔invasive species - ✔✔Not native and has negative effects on economy,
environment, or health