BIOL 1020 and BIOL 1021 - Lecture 12
- Cycling Carbon -
Assigned Readings in Textbook:
Chapter 25 (section 25.1) – The Short-Term Carbon Cycle (pages 510 to 515)
Chapter 25 (section 25.2) – The Long-Term Carbon Cycle (pages 515 to 520)
Chapter 25 (section 25.3) – The Carbon Cycle: Ecology, Biodiversity and Evolution (pages 521 to 523)
Use the following wireframe outline to make notes on the content presented in Lecture 12
Refer to Chapter 25 in your textbook and the Chapter 25 resources on LaunchPad to supplement
your notes and aid in studying this material.
1. What is the carbon cycle?
- Key process in ecology
- An intricately – linked network of biological, chemical and physical processes
- Moves carbon among lithosphere, hydrosphere, atmosphere
(a) What is a “biogeochemical cycle”? A carbon cycle
Reservoir – units of gigatons
Flux – units of gigatons
C/year
1
, (b) Rank the components of the carbon cycle from slowest to fastest.
BIOLOGY – FAST
CHEMICAL – SLOW
GEOLOGY – VERY SLOW
2. What are the key pathways for the short-term carbon cycle?
(a) What is involved in the biological component?
Photosynthesis and Respiration
(b) What short-term seasonal patterns have been observed?
1. CO2 levels in atmosphere show seasonal oscillations in northern hemisphere
photosynthesis is seasonal
respiration remains constant throughout year
seasonal oscillations are more significant in northern hemisphere
2. Results of study done by Charles Keeling:
Saw pattern of seasonal oscillation – spring high/fall low
Summer removal of CO2 does not balance winter addition leading to increase
Over period of monitoring, C02 levels have increased
(c) What is the cause? Why have CO2 levels increased?
Increase in atmospheric C02 levels started in 1800s
Coincides with onset of Industrial Revolution
Correlates with increased use of fossil fuels by humans
(d) What are the consequences?
Sustained increase in atmospheric CO2 levels since 1958
In 1960s – increase in 1 ppm per year
From 2001 t0 2010 – increase of 2 ppm per year
Levels of atmospheric CO2 are 25% higher than 50 years ago
Highest levels in last 650 000 years
Human activity = driving force behind climate change
(e) Are these trends unusual?
No considering all the pollutions humans contribute negatively
2
- Cycling Carbon -
Assigned Readings in Textbook:
Chapter 25 (section 25.1) – The Short-Term Carbon Cycle (pages 510 to 515)
Chapter 25 (section 25.2) – The Long-Term Carbon Cycle (pages 515 to 520)
Chapter 25 (section 25.3) – The Carbon Cycle: Ecology, Biodiversity and Evolution (pages 521 to 523)
Use the following wireframe outline to make notes on the content presented in Lecture 12
Refer to Chapter 25 in your textbook and the Chapter 25 resources on LaunchPad to supplement
your notes and aid in studying this material.
1. What is the carbon cycle?
- Key process in ecology
- An intricately – linked network of biological, chemical and physical processes
- Moves carbon among lithosphere, hydrosphere, atmosphere
(a) What is a “biogeochemical cycle”? A carbon cycle
Reservoir – units of gigatons
Flux – units of gigatons
C/year
1
, (b) Rank the components of the carbon cycle from slowest to fastest.
BIOLOGY – FAST
CHEMICAL – SLOW
GEOLOGY – VERY SLOW
2. What are the key pathways for the short-term carbon cycle?
(a) What is involved in the biological component?
Photosynthesis and Respiration
(b) What short-term seasonal patterns have been observed?
1. CO2 levels in atmosphere show seasonal oscillations in northern hemisphere
photosynthesis is seasonal
respiration remains constant throughout year
seasonal oscillations are more significant in northern hemisphere
2. Results of study done by Charles Keeling:
Saw pattern of seasonal oscillation – spring high/fall low
Summer removal of CO2 does not balance winter addition leading to increase
Over period of monitoring, C02 levels have increased
(c) What is the cause? Why have CO2 levels increased?
Increase in atmospheric C02 levels started in 1800s
Coincides with onset of Industrial Revolution
Correlates with increased use of fossil fuels by humans
(d) What are the consequences?
Sustained increase in atmospheric CO2 levels since 1958
In 1960s – increase in 1 ppm per year
From 2001 t0 2010 – increase of 2 ppm per year
Levels of atmospheric CO2 are 25% higher than 50 years ago
Highest levels in last 650 000 years
Human activity = driving force behind climate change
(e) Are these trends unusual?
No considering all the pollutions humans contribute negatively
2
