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Science AHSGE
Standard II-1, part 3- Biogeochemical Processes
Nutrients
Nutrient- Substance necessary for life– Must obtain from the environment to sustain life
and carry out life processes– Examples: Oxygen, water, carbon, nitrogen and
phorphorous– Obtained in the form of elements and compounds
from air, water, food, or soil– Biogeochemical Cycle- Involves living organisms
(bio), geological processes (geo) and chemical processes (chemical)
Water Cycle Hydrology- Study of water and the cycling of
it through the environment Sources: River, ocean, ponds/lakes, streams,
aquifers, ice caps, or glaciers Two types: Salt (ocean), fresh water (ponds,
lakes, rivers, streams), brackish water (swamps, anywhere rivers empty into ocean)
Water Cycle
Two ways to get liquid from vapor: precipitation (snow, rain, sleet, hail), condensation (gas to a liquid)
Two ways to get water vapor from liquid: evaporation (liquid to a gas) and transpiration (loss of water from a plant through the stomata)
Runoff- Surface water continually moves until it reaches a water source
Infiltration- Water soaking into the ground Water table- Point of saturation under the ground
Carbon and Oxygen Cycles All living things composed of molecules
containing carbon Organic- Any substance containing carbon
and oxygen Carbon and oxygen are recycled quickly
through living things– Autotrophs/producers- photosynthesis– Consumers/decomposers/heterotrophs- cellular
(aerobic) respiration
Carbon and Oxygen Cycles
Carbon enters into cycle long term when buried underground and converted to peat, coal, oil, or natural gas deposits (millions of years)– Released back to the atmosphere as CO2 when
fossil fuels are burned
Carbon and oxygen can enter a long-term cycle in the form of calcium carbonate (chalk) or limestone– Remain trapped in deposits until erosion occurs
Carbon and Oxygen Cycles
Nitrogen Cycle
Element needed to produce proteins Plants and animals can not use directly from
atmosphere Nitrogen Fixation
– Nitrogen gas is captured by bacteria in air, soil, water and on the roots of some plants (legumes)
– Converted into a useful form for plants • Nitrate- Inorganic nitrogen compound converted from
ammonia• Energy from lightning bolts can also convert
Nitrogen Cycle
Plants absorb nitrates from soil and convert to proteins
Consumers get nitrogen from eating plants or other animals
Fixed nitrogen is in limited supply, so this element is a factor that limits the growth of producers
Nitrogen Cycle
Nitrogen returns to soil:– Animal urination– Decomposers break down dead organisms into
the nitrogen compound ammonia– Organisms in the soil convert ammonia into
nitrogen compounds to be used by plants
Denitrification- Soil bacteria convert fixed nitrogen compounds back into nitrogen gas, which returns to the atmosphere
Phosphorus Cycle
Essential for growth and development of organisms– Found in various compounds of cells– Large amounts concentrated in bones and teeth
Phosphorus, in the form of phosphates, are present in small amounts in soil and water– Often a factor that limits the growth of producers
Phosphorus Cycle
Short-term cycle– Cycled from soil to
producers and then to consumers
– Organisms die returning phosphorus to soil to be used again
Long-term cycle– Weathering or
erosion of rocks containing phosphorus slowly add to the cycle
Phosphorus Cycle