Chapter 6 Notes
Earth is a Peculiar Planet:
-Four unique charecteristics:
~Liquid Water
~Plate tectonics
~life
-life has a large effect on biogeochemical cycling
~Liquid Water
~Plate tectonics
~life
-life has a large effect on biogeochemical cycling
Planets near earth:
-inner planets formed by gathering together of particle by gravitational force
~would expect earth, mars, mercury and Venus to have a similar atmosphere-they do not
~would expect earth, mars, mercury and Venus to have a similar atmosphere-they do not
Rise of Oxygen:
-Before 2.3 billion years ago the atmosphere was low in oxygen
~ evidence-grains of pyrite in sedimentary rock
~Oceans were filled with dissolved iron
-Evolution of Photosynthesis brought about gaseous oxygen
~photosynthesis-carbon dioxide and water are combined in presence of light to create sugars and free oxygen
-Took 2 billion years before oxygen started to accumulate in atmosphere
~ first it oxidized all the un-oxidized iron
-Early photosynthesizes included stomatolites (3.4 billion years old)
Early organisms on earth
-Prokaryotes
~Lacked organelles and a nucleus (too much energy to maintain)
-Get energy from fermentation
~low energy yield to organism
~waste products of carbon dioxide and alcohol
-live singly or in end to end chains
-cannot form 3-D
-Eukaryotas
~use oxygen for respiration
~larger cells with nucleus and organelles
~from 3-D colony of cells
~Permits multi-cellular body structure of plants, animals and fungi
Evolution of biosphere
-after presence of Eukaryotas and oxygenated atmosphere
~biosphere started to change drastically
~Plants, animals and fungi evolved 700-500 million years ago
~they, in turn, continued to alter the biogeochemical cycles on earth
~ evidence-grains of pyrite in sedimentary rock
~Oceans were filled with dissolved iron
-Evolution of Photosynthesis brought about gaseous oxygen
~photosynthesis-carbon dioxide and water are combined in presence of light to create sugars and free oxygen
-Took 2 billion years before oxygen started to accumulate in atmosphere
~ first it oxidized all the un-oxidized iron
-Early photosynthesizes included stomatolites (3.4 billion years old)
Early organisms on earth
-Prokaryotes
~Lacked organelles and a nucleus (too much energy to maintain)
-Get energy from fermentation
~low energy yield to organism
~waste products of carbon dioxide and alcohol
-live singly or in end to end chains
-cannot form 3-D
-Eukaryotas
~use oxygen for respiration
~larger cells with nucleus and organelles
~from 3-D colony of cells
~Permits multi-cellular body structure of plants, animals and fungi
Evolution of biosphere
-after presence of Eukaryotas and oxygenated atmosphere
~biosphere started to change drastically
~Plants, animals and fungi evolved 700-500 million years ago
~they, in turn, continued to alter the biogeochemical cycles on earth
Life and Global Chemical Cycles:
-Micro-nutrients
~elements required in small amounts by all life or moderate amount by some forms of life
-macro-nutrients
~24 elements required by all organisms
~include the BIG SIX which are the building blocks of life
~carbon, oxygen, hydrogen, nitrogen, phosphorus, sulfur
~each plays a special role in organisms
-for life to persist elements must be available at the right time, in the right amount, and in right concentrations relative to one another
~too much of some elements- can be toxic
~too little of some element-can limit growth and development
~neutral-some elements are neutral for life
biogeochemical cycles
-The complete path a chemical takes through the 4 major components of earth's system
~atmosphere
~hydrosphere
~lithosphere
~biosphere
~elements required in small amounts by all life or moderate amount by some forms of life
-macro-nutrients
~24 elements required by all organisms
~include the BIG SIX which are the building blocks of life
~carbon, oxygen, hydrogen, nitrogen, phosphorus, sulfur
~each plays a special role in organisms
-for life to persist elements must be available at the right time, in the right amount, and in right concentrations relative to one another
~too much of some elements- can be toxic
~too little of some element-can limit growth and development
~neutral-some elements are neutral for life
biogeochemical cycles
-The complete path a chemical takes through the 4 major components of earth's system
~atmosphere
~hydrosphere
~lithosphere
~biosphere
General aspects of biogeochemical cycles:
-some chemicals cycle quickly and are readily regenerated for biological activity
~they typically have a gas phase, are voluble and carried by the hydro-logic cycle
~oxygen and nitrogen
-other chemical elements are relatively immobile and returned by geogical processes
~typically lack a gas phase and insoluble
~phosphorus
-most required nutrients are light
~heaviest is iodine with atomic weight of 53
-since life evolved it has altered biogeochemical cycles
~the continuation of processes that control biogeochemical cycles essential for maintenance of life
-through modern technology transfer rate of elements into air, water, and soil altered
~may benefit society but may also pose environment hazard
~must recognize the +and- consequences of altering cycles simplest way to view a cycle is a box and arrow diagram
~boxes represent places where a chemical is stored
~donating compartment is a source
~receiving compartment is a sink
~amount of time an atom spends in any compartment is called its residence time
~arrows represent pathways of transfer
~flow is the amount moving from one box to another
~flux is the rate of transfer the geologic cycle
-rocks and soil
~continually created, maintained, changed and destroyed over the last 4.6 billion years
~altered due to physical, chemical, and biological processed
-geologic cycle-group of cycle
~tectonic
~hydro
-logic
~rock
~biogeochemical
~they typically have a gas phase, are voluble and carried by the hydro-logic cycle
~oxygen and nitrogen
-other chemical elements are relatively immobile and returned by geogical processes
~typically lack a gas phase and insoluble
~phosphorus
-most required nutrients are light
~heaviest is iodine with atomic weight of 53
-since life evolved it has altered biogeochemical cycles
~the continuation of processes that control biogeochemical cycles essential for maintenance of life
-through modern technology transfer rate of elements into air, water, and soil altered
~may benefit society but may also pose environment hazard
~must recognize the +and- consequences of altering cycles simplest way to view a cycle is a box and arrow diagram
~boxes represent places where a chemical is stored
~donating compartment is a source
~receiving compartment is a sink
~amount of time an atom spends in any compartment is called its residence time
~arrows represent pathways of transfer
~flow is the amount moving from one box to another
~flux is the rate of transfer the geologic cycle
-rocks and soil
~continually created, maintained, changed and destroyed over the last 4.6 billion years
~altered due to physical, chemical, and biological processed
-geologic cycle-group of cycle
~tectonic
~hydro
-logic
~rock
~biogeochemical
The teconic cycle:
-involves creation and destruction of the lithosphere (outer layer of earth)
~ ~100km thick and broken in to several plates
~the slow movement of plates is called plate tectonics
~2-15cm/yr
-plate tectonics has large scales effects
~location and size of continents
~alterations in climate
~ecological islands
~areas of volcanic activity and earthquakes
~ ~100km thick and broken in to several plates
~the slow movement of plates is called plate tectonics
~2-15cm/yr
-plate tectonics has large scales effects
~location and size of continents
~alterations in climate
~ecological islands
~areas of volcanic activity and earthquakes
Types of plate boundaries:
1.divergent plate boundary
~occurs at a spreading ocean ridge, where plantes moving away from 1 another
~new lithosphere produced
~known as sea floor spreading, produces ocean basins
2. convergent plate boundary
~occurs when plates collide
~when heavier ocean plates meet lighter continental plates a subduction zone is present
~when 2 lighter continental plates collide a continental mountain range may form
3. transform fault boundary
~occurs where 1 plate sides past another
~san andreas fault california
~boundary of NA and Pacific plates
~LA moving towards SF
~occurs at a spreading ocean ridge, where plantes moving away from 1 another
~new lithosphere produced
~known as sea floor spreading, produces ocean basins
2. convergent plate boundary
~occurs when plates collide
~when heavier ocean plates meet lighter continental plates a subduction zone is present
~when 2 lighter continental plates collide a continental mountain range may form
3. transform fault boundary
~occurs where 1 plate sides past another
~san andreas fault california
~boundary of NA and Pacific plates
~LA moving towards SF
The Hydrologic Cycle:
-The transfer of water from oceans to the atmosphere to the land and back to the oceans
- driven by solar enery
~evaporation of water from oceans
~precipitation of water on land
~transpiration of water by plants
~evaporation of water from land
~runoff from streams, rivers and subsurface groundwater
total water on earth=1.3 billion km3
~97% in oceans
2% in glaciers and ice caps
~0.001% in atmosphere
~the rest in fresh water on land
-at the regional and local level, the fundamental unit of the landscape is the draiage basin
~the area that contributes surface runoff to a particular stream or river
~vary greatly in size
~usually named for main stream or river
- driven by solar enery
~evaporation of water from oceans
~precipitation of water on land
~transpiration of water by plants
~evaporation of water from land
~runoff from streams, rivers and subsurface groundwater
total water on earth=1.3 billion km3
~97% in oceans
2% in glaciers and ice caps
~0.001% in atmosphere
~the rest in fresh water on land
-at the regional and local level, the fundamental unit of the landscape is the draiage basin
~the area that contributes surface runoff to a particular stream or river
~vary greatly in size
~usually named for main stream or river
The Rock Cycle:
-consists of numerous processes that produce rocks and soils
-depends of the tectonic cycle for energy and the hydrologic cycle for water
-rocks classified as
~igneous
~sedimentary
~metamorphic
-physical weathering(freeze,thaw) produces sediment such as gravel, sand and silt.
-chemical weathering occurs when weak acids in water dissolve chemicals from rocks
-depends of the tectonic cycle for energy and the hydrologic cycle for water
-rocks classified as
~igneous
~sedimentary
~metamorphic
-physical weathering(freeze,thaw) produces sediment such as gravel, sand and silt.
-chemical weathering occurs when weak acids in water dissolve chemicals from rocks
The Carbon Cycle:
-is the element that anchors all organic substances
-carbon has a gaseous phrase
~Enters atmosphere (CO2 and CH4) through respiration, fires and diffusion
~removed from the atmosphere by photosynthesis
-carbon occurs in the ocean in several forms
~dissolved CO2 carbonate and bicarbonate
~marine organisms and their products, CaCO3
-enters the ocean by
~simple diffusion then dissolves
~transfer from land in rivers as dissolved carbon
-carbon enters the biota through photosynthesis and then returned by respiration or fire
~ when organism dies docomposition releases carbon
~if buried under certain conditions carbon is not be released
~transformed into fossil duels
-carbon has a gaseous phrase
~Enters atmosphere (CO2 and CH4) through respiration, fires and diffusion
~removed from the atmosphere by photosynthesis
-carbon occurs in the ocean in several forms
~dissolved CO2 carbonate and bicarbonate
~marine organisms and their products, CaCO3
-enters the ocean by
~simple diffusion then dissolves
~transfer from land in rivers as dissolved carbon
-carbon enters the biota through photosynthesis and then returned by respiration or fire
~ when organism dies docomposition releases carbon
~if buried under certain conditions carbon is not be released
~transformed into fossil duels
The Carbon-Silicate Cycle:
-The cycling of carbon intimately involved with the cycling of silicon
-weak carbonic acid falls as rain and weathers silicate rich rocks
~releases Ca2+ and HCO3-
~transferred to oceans and used by marine animals to contructs shells
~shells deposited on sea floor become part of sed rock layer and return to surface in subduction zones
-weak carbonic acid falls as rain and weathers silicate rich rocks
~releases Ca2+ and HCO3-
~transferred to oceans and used by marine animals to contructs shells
~shells deposited on sea floor become part of sed rock layer and return to surface in subduction zones
The nitrogen cycle:
-N essential to life because it is necessary for the production of proteins and DNA
-Free N2 makes up 78% of atmosphere
~but most organisms can't use it directly
~relatively unreactive element must be converted to NO3- or NH4+
~performed by bacteria
-nitrogen fixation-process of converting atmospheric N to NO3- or NH4+
-denitrification-process of releasing fixed N back to molecular N
-almost all organisms depend on N converting bacteria
~some have formed symbiotic relationships in the roots of plants or stomach on animals-Industrial process can now convert molecular N into compounds usable by plants
~main component of N fertilizers
~N in agricultural runoff potential source of water poluution
-N combines with O at high temperatures
~oxides of N a source of air pollution
The Phosphorus Cycle
-P 1 of the "bug 6" required for life
~often a limiting favtor for plant and algal growth
-does not have a gaseous phase
~rate of transfer slow
The Phosphorus Cycle
-Enters biota through uptake as phosphate by plants, algae and some bacteria
~returns to soil when plants die or is lost to oceans via ruunoff
~returned to land via ocean feeding birds (guano)
-Guano depeosits major source of P for fertilizers
-Free N2 makes up 78% of atmosphere
~but most organisms can't use it directly
~relatively unreactive element must be converted to NO3- or NH4+
~performed by bacteria
-nitrogen fixation-process of converting atmospheric N to NO3- or NH4+
-denitrification-process of releasing fixed N back to molecular N
-almost all organisms depend on N converting bacteria
~some have formed symbiotic relationships in the roots of plants or stomach on animals-Industrial process can now convert molecular N into compounds usable by plants
~main component of N fertilizers
~N in agricultural runoff potential source of water poluution
-N combines with O at high temperatures
~oxides of N a source of air pollution
The Phosphorus Cycle
-P 1 of the "bug 6" required for life
~often a limiting favtor for plant and algal growth
-does not have a gaseous phase
~rate of transfer slow
The Phosphorus Cycle
-Enters biota through uptake as phosphate by plants, algae and some bacteria
~returns to soil when plants die or is lost to oceans via ruunoff
~returned to land via ocean feeding birds (guano)
-Guano depeosits major source of P for fertilizers