Chapter 25 - Cycling Carbon Flashcards
What did Keeling notice about CO2 levels?
- CO2 concentration reached its annual high point in spring then declined by 6 ppm to a minimum in early fall
- However, summertime removal of CO2 did not balance winter increase - up to now it has increased more than 25%
What does 6 ppm mean in terms relative to CO2 levels?
Approximately 47 billion metric tons of CO2 were entering and leaving the atmosphere annually
What exactly the carbon cycle?
The intricately linked network of biological and physical processes that shuttles carbon among rocks, soil, oceans, air, and organisms.
What is the significance of the carbon cycle?
It provides a glimpse of the interactions that underpin ecology and promote biological diversity
What processes introduce CO2 to the atmosphere?
- geological inputs (volcanoes)
- biological inputs (respiration)
- human activities (burning of fossil fuels)
What processes remove CO2 from the atmosphere?
- geologic removal
2. biological removal (photosynthesis)
What is the role and function of photosynthesis?
Photosynthesis convert energy from the sun into ATP, which they use to reduce CO2 to sugar. Carbon is then transferred to carbohydrates and oxygen is given off as a byproduct.
6CO2+6H20–>C6H1206+6O2
What percent of annual CO2 does photosynthesis remove?
25%
What is the role and function of respiration?
It uses oxygen to oxidize organic molecules to CO2, converting chemical energy in the organic compounds to ATP for use in cellular processes. Can be summarized by:
C6H1206+6O2–>6CO2+6H20
Why does the Keeling curve demonstrate an upward increase in CO2?
Because of human burning of fossil fuels, which contributes a certain isotope of carbon
How much CO2 was in the atmosphere 1000 years ago and how can we test for that?
When glacial ice forms in Antarctica and Greenland, it traps tiny bubbles of air, accumulating in layers.
How can we tell that there is a causation between the industrial revolution and increased CO2 in the atmosphere?
Hans Suess measured relative abundances of 13C and 12C, which seemed to decrease, but 14C has increased, which indicates there is an increase due to fossil fuels.
We find that half of CO2 released by human activities did not end up in air - where does it go?
It’s stored in oceans in the form of ions and salts.
What is a primary producer and what are some examples?
Organisms that generate organic compounds that will provide food for other organisms in the local environment
Ex: plants, bacteria
What is a consumer and what are some examples?
Organisms that obtain the carbon they need for growth and reproduction from the foods they eat, and they also gain energy by respiring food molecules
Ex: insects eating leaves, ducks eating algae
What are decomposers and what are some examples?
Organisms that break down dead tissues
Ex: fungi, bacteria
What is the food chain?
The linear transfer of carbon from one organism to another
What is a food web?
An alternative to the food chain - showing the complexity of interactions and carbon consumers within the carbon cycle
What are trophic pyramids/how are they used?
They are diagrams that show the amount of energy available at each level to feed the next-
What is the pattern of trophic pyramids?
The higher the trophic level, the less available energy. This is because energy transfer is inefficient from level to level. Only 10-15% of levels are incorporated into biomass at the next level.
Why is there such photosynthetic organism diversity?
Organisms all live in different habitats, and each is specialized to its unique habitat. This reflects structural and physiological adaptations.
What can the carbon cycle tell us about evolution?
It changed the nature of Earth surface environments in ways that enabled new types of organisms to evolve
How did the present carbon cycle come to be?
When photosynthesis and respiration are in balance, the oxygen generated by photosynthesis is completely consumed by respiration, but oxygen production can also exceed oxygen consumption. It can facilitate an increase in oxygen levels which is why our world is oxygen-rich
