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CO2, Global Warming, Climate Change
Global Warming: the Earth's rising surface temperature due to the rapid increase in CO2 and other greenhouse gases
produced by people. (Global Scale)
- Who/What Causes: Human activity
- Factors: CO2 and other GHGs
- Result: Rise in GLOBAL surface temperatures
Climate Change: global warming's side effects, includes both human and natural changes (Local, Region, and Global
Scales)
- Who/What Causes: Both human and natural
- Factors: Volcanoes, plate tectonics, changes in oceans, pollution, deforestation, and some GHGs
- Result: New weather patterns, rise in temperature, changes in sea level, disappearance of ice, more drought.
Proxy Data: Data we can collect to infer something else that we can't measure today (climate/temperature in the past),
physical characteristics (tree rings/ice cores) that can be measured today that show a record of something in the past.
(Back Casting)
- Must have an established relationship between the proxy variable and the variable of interest.
- Many times we are more interested in the change in temperature, not the exact temperature.
EX. Ice cores: their isotopic signature (ratio of hydrogen and oxygen isotopes) systematically changes depending
on the air temperature at the time the snow is produced and falls to the earth. (may not need to know for test)
CO2:
- Produced by: fossil fuels (huge change), land use change (small change)
- Where to: Ocean sink (<1/3), Land sink (<1/3), atmosphere (>1/3)
Representative Concentration Pathway (RCP):
- Best case: 2.6 difference if significant measures are taken to curb CO2 emissions.
- Worst case: 8.5 difference if nothing is done.
With increased CO2 emissions, ocean temperatures will rise drastically, extreme storms will frequent, >2 feet rise
in sea level
- Precipitation: will likely increase in areas where blizzards are common and decrease in areas where drought is
Phenology: the timing of life events (migration, mating/reproduction, emergence/hibernation/dormancy) of a species.
Usually based on daylength vs. temperature.
- Could result in a lack of synchrony between the phenology of consumers and their food source (trophic mismatch)
EX. Triggers mating season (daylength) vs. warming temperatures causing plants to emerge earlier (temperature)
EX. Deer are often born at a certain time of year (daylength) vs. when grasses bloom (temperature)
What can animals/plants do?
- Acclimate: change morphology, physiology, or behavior
- Shift their range: moving up north, or up in altitude (birds moving up a mountain)
- Evolve: genetic variation
- Extinct: die
GHGs
- Make up <0.1% of the amosphere
- Of that 0.1%: 93.5% is CO
Global Warming Potential (GHP): based on residence time and ability to absorb energy
- GWP of:
- CO2: 1 < CH4: 21 < N2O: 298 < F-gases: 14,
Water Vapor?
- Most abundant GHG in atmosphere
- Natural product, mostly not humans fault
Study Guide (Unit 2)
Tuesday, February 20, 2024 11:28 AM
Arrow colors:
Yellow = short wavelength UV radiation from the sun and short visible light from the sun
Orange = long wavelength infrared radiation (heat) radiating from earth's surface
Red = long wavelength infrared radiation (heat) emitted by GHGs
IMPORTANT!
NO GHG can: absorb short wavelength UV radiation or visible light from the sun
ALL GHGs (CO2, Water Vapor, CH4): can absorb long wavelength infrared radiation from earth's surface
- The amount of radiation coming from the sun is based on:
- Solar output from the sun (doesn't affect GW)
- Milankovitch Cycles: Distance from the sun (very long-term fluctuations), ice ages are caused by these
Natural Source of GHGs:
- Volcanoes, decomposition, fires, geologic leaching, melting permafrost, respiration, denitrification
Anthropogenic Sources of GHGs:
Burning fossil fuels, cement curing, land use conversion, resource extraction, agriculture, coolants/industrial
practices (F-gases)
What produces the C:
- Volcanism, combustion, respiration, decomposition, photosynthesis, diffusion, sedimentation (LONG)
Where C is stored:
- animals and plants, soil, atmosphere, ocean (LONG), fossil fuels (LONG), rock (LONG)
- Warm water absorbs less CO2, so warming oceans have less CO2 in them --> goes to the atmosphere
Feedback Loops
- Negative:
- Favor changes that lead back toward stability/equilibrium
- Dampen the effect of initial stimulus
- Positive:
- Promote farther change toward and extreme
- Amplify (up/down) the effect of initial stimulus
- Ocean CO2:
- Air T (^^^), Water T (^^^), CO2 solubility (vvv), CO2 in atm (^^^) BAD
- Water Vapor:
- Chlorophyll contains 4 nitrogen (and a Mg), these are usually limiting factors to growth
- Carotenoids contain long CH3 chains, which are abundant elements. (REMEMBER: they reflect yellow-red more)
ANSWER: When N becomes limiting, chlorophyll is broken down which
Steps of Photosynthesis
Light Dependent Reactions:
PS2 STEPS (Thylakoid Membrane)
- H2O (soil) and Light (sun) enter the thylakoid through chlorophyll -->
- PS2 accepts photons through an e- acceptor and excites e-(comes from H2O splitting into O2 and two protons) -->
e- (HIGH E) sent to e- transport chain
- H+ sent to thylakoid lumen (eventually turned into ATP)
Reactants: H2O, light
Products: O2, e- (HIGH E)
e- Transport Chain STEPS (Thylakoid Membrane + Lumen)
- e- (HIGH E) from PS2 is passed from protein to protein
- H+ is moved from the stroma to the thylakoid lumen because of the e- (HIGH E)
- e- (LOW E) is sent to PS
H+ is also pumped in by the actions of the e- transport chain (creating a proton gradient, more on inside of
thylakoid, creates need for ATP synthase)
Reactants: e- (HIGH E)
Products: H+, e- (LOW E)
ATP Synthase (Thylakoid Lumen --> Stroma)
- Connects high concentration H+ (inside lumen) to low concentration H+ (stroma)
Reactants: H+
Products: ATP
PS1 STEPS (Thylakoid Membrane)
- Chlorophyll absorbs light (sun) and causes an e- (HIGH E) to become excited -->
- NADP+ reductase receives e- and uses the energy to make NADPH -->
- The e- PS1 sends to reductase is replaced by low energy e- from e- transport chain
Reactants: Light, e- (LOW E)
Products: NADPH
Light Independent Reactions:
Calvin Cycle (Stroma) [3 Cycles]
STEP 1: Carbon Fixation
- 3 CO2 molecules+ 3 5C RuBP enzymes catalyzed --> 6 3-PGA molecules
STEP 2: Reduction
- 6 3-PGA + ATP/NADPH --> 6 G3P (3C)
STEP 3: Regeneration
- 1 G3P + glucogenesis --> 1/2 glucose
- 1 G3P + glucogenesis --> 1/2 glucose
- 5 G3P --> RuBP (continue cycle)
FULL CYCLE:
- 3 CO2 --> 6 3-PGA --> 6 G3P --> [1 G3P --> 1/2 glucose] + [5 G3P --> RuBP]
• THIS PROCESS REQUIRES 6 TURNS (3 ARE ACCOUNTED FOR IN THE EXAMPLE ABOVE)
So… 6 CO2 + 18 ATP + 12 NADPH --> 1 molecule Glucose
!!! YOU DON’T NEED TO KNOW THE EXACT NUMBERS FOR EACH, just know 1 G3P contains 3 Carbon (3 cycles) and 1
glucose contains 2 G3P (6 cycles)
Issues with Photosynthesis
H2O Loss
- Water is lose through stomata (about 100 H2O per 1 CO2 acquired)
Why is H2O needed?
- Replaces the e- PS2 donates to e- transport chain, leading to the production of ATP from the H+
Gives plants structure through Turgor pressure (pressure exerted by fluid in a cell that presses the membrane
against the cell wall, makes plants rigid)
Water Movement in plants is caused by?
- Transpiration: evaporation of water vapor from leaves through stomata
- Adhesion/Cohesion: water tends to bond to other surfaces and itself to creep up toward the top of plants.
- Water Potential: areas with more negative values attract water (top of plant)
Rubisco O2 Fixation
- Under hot, dry conditions, stomata close to prevent H2O loss -->
This causes a decrease in CO2 and the same amount of O2 being produced from light dependent reactions -->
- Rubisco fixes to O2 and wastes energy and carbon -->
- Photorespiration: Rubisco binds to O2 and wastes carbon, Calvin Cycle is not repeated
This leads to…
C3 vs. C4 vs. CAM
C
- No changes, photorespiration occurs, but overall growth in optimal conditions is much faster
C4 (bombs change a location)
- Location of C Cycle changes
Rubisco is kept in the bundle sheath cells so even if high concentrations of O2 are prevalent in the mesophyll,
photorespiration will not occur.
STEPS:
- CO2 enters the cytosol of mesophyll cells and is initially fixed by the enzyme PEP Carboxylase
- CO2 is fixed by a Oxaloacetate (4C molecule)
- Converted to malate (4C molecule)
- CO2 then enters the bundle sheath cell and goes through the C Cycle
CAM (cameras capture a moment in time)
- Timing of when CO2 is fixed changes
STEPS:
- At NIGHT the stomata open allowing CO2 in
- PEP carboxylase is used instead of Rubisco
