EE Lecture 22: Carbon

Question 1

when did life begin (in terms of RNA)

Answer 1

when self replicating C-N molecules like RNA began to use energy for homeostasis

Question 2

what does carbon recycling mean

Answer 2

returned to inorganic from by respiration

Question 3

what is carbon flux

Answer 3

rate of carbon transfer between pools

Question 4

name some carbon sources

Answer 4

fossil fuel burning
respiration
deforestation - slash and burn
decomposition

Question 5

name some carbon sinks

Answer 5

biomass - peat formation in bogs

sediments

Question 6

what is carbon fixation balanced by

Answer 6

respiration

Question 7

why is carbon at equilibrium in biomass

Answer 7

because biomass s neither a sink nor source - fixation is balanced by respiration

Question 8

name some inorganic carbon pools

Answer 8

rocks
sediments
gases
water 
clathrates

Question 9

how many orders of magintude difference of C between litho- hydro- and atmosphere

Answer 9

2 orders of magnitude difference between each component

Question 10

where are clathrates found

Answer 10

worldwide

Question 11

what are clathrates associated with

Answer 11

onshore and off shore permafrost

Question 12

what can clathrates trigger? why/how

Answer 12

clathrates lie beneath submarine slopes and can contribute to landslides when seabed temp rises

Question 13

what are clathrates

Answer 13

solid chemical lattice - traps methane >10^19 gC

Question 14

what potential use is there for clathrates

Answer 14

potential fuel source

Question 15

what hazard do clathrates pose

Answer 15

major hazard for global warming

Question 16

how many molecules of methane does each clathrate cage typically contain

Answer 16

1 molecule of methane per clathrate cage

Question 17

what is the clathrate gun hypothesis

Answer 17

1. energy gun is loaded as clathrates build up during cold periods
2. the gun is fired to cause rapid greenhouse warming (positive feedback)
3. process occurs on different timescales and magnitudes
4. produces a well documented saw tooth pattern of temp change

Question 18

how many MYA was the latest paleocene thermal max

what was it to do with

Answer 18

55MYA

rapid warming of sea due to 2x10^8 methane transferred from clathrates to ocean

Question 19

in the clathrate gun hypothesis what is the gun

Answer 19

gun gets loaded during cold periods by clathrate build uip

Question 20

what are units of carbon in carbon cycle`

Answer 20

petagrams

Question 21

what are the main carbon flows in the carbon cycle

Answer 21

ocean to atmosphere
photosynthesis and respiration
deocmposition

Question 22

outline main steps of carbon cycle

Answer 22

fixation
respiration
litter fall
herbivory
root dynamics
C input to streams (allochthonous)
C fixed in steams (autochthonous)
sedimentation in lake
export open system

Question 23

what does allochthonous mean

Answer 23

C input into streams

Question 24

what does autochthonous mean

Answer 24

C fization in streams

Question 25

what are the consequences of increased CO2 due to

Answer 25

immediate increase in photosynth in C3 plants often disappears under long exposure increase biomass and food production root shoot ratios increase N fixers benefit more than other plants

Question 26

what consequences does an increase CO2 in C3 plants have

Answer 26

immediate increase in photosynth in C3 plants often disappears under long exposure, suggesting homeostasis

Question 27

what consequences does an increase CO2 on root shoot raitos have

Answer 27

root shoot ratios increase when increase CO2

Question 28

which type of plants benefit more from an increased CO2 conc

Answer 28

N fixers

Question 29

what is tau - τ

Answer 29

mean residence time

Question 30

what is the symbol for mean residence time

Answer 30

tau

Question 31

what is eqtn for tau

Answer 31

tau = mass/flux

Question 32

what does mass/flux equal

Answer 32

mean residence time - tau

Question 33

what does tau help you work out

Answer 33

how much an increase in respiration would lag photosynthesis by in response to linear folding tau is measured in years

Question 34

what is tau measured in?

Answer 34

yrs/unit of time

Question 35

If t was 40yrs, for a 2Gt per year terrestrial sink, what would global NPP be going up by? what would rate of global CO2 increase per year be

Answer 35

2/40 = 0.05Gt per year

Question 36

write formular for measuring C sink from tau

Answer 36

C sink = ΔNPP x τ

Question 37

what does tau measure

Answer 37

rate of global CO2 increase per year/unit of time

Question 38

what is the most parsimonious explanation for increasing forest growth

Answer 38

forest have more net C sink, more CO2 resource causing an increase NPP

Question 39

how do C and N pollutants interact

Answer 39

fertilizer effects increase biomass pools of both nutrients