Lecture 5 - Life Energy and Life

Question 1

Carbon Cycle

Answer 1

Overtime –> lost back to atmosphere or buried below earth (sediments)

Question 2

Carbon Cycle

Sediments

Answer 2

Old carbon
- Either incorporated into rocks (fossils)

or

-If conditions are right –> converted into fossil fuels –> non-renewable

Question 3

Carbon Cycle

Out of balance

Answer 3

-Humans accelerate release of CO2
-Rate of removal stays the same
-pH dropped –> 8.1 - 8.0
-Acidity increased by 25%

Question 4

Nitrogen Cycle

Answer 4

-Needed for many essential organic molecules
*Amino acids
* Peptides
*Nucleic acids

-Most abundant element in the atmosphere

Question 5

Nitrogen Cycle

Steps

Answer 5

1. Nitrogen Fixing Bacteria make usable for plants (atmosphere –> soil)
2. Organisms use it
   *die, shed parts or release bi-products
3. Denitrifying bacteria then break it down back into gas
4. Cycle is done

Question 6

Nitrogen Cycle

Problem

Answer 6

-Agriculture huge footprint
-Responsible for low-cost food
-Less farm land –> feed more people
-high soluble in water
-Low supply in aquatic ecosystems *who can grab nitrogen first
-When nitrogen increases –> algae and plants use it to grow quickly

Cynobacterial Algae Bloom

Question 7

Phosphorus Cycle

Answer 7

Becomes available to organisms after it is released from rocks

*highly used as preservative
*goes into rivers

Question 8

Phosphorus Cycle

Steps

Answer 8

1. P drained from rocks and minerals
2. Taken by producers, then consumers
3. Return to environment by decomposition
   *no atmospheric stage

Question 9

Phosphorus Cycle

Eutrophication

Answer 9

Phosphorus and nitrogen become deadly to plans, humans and animals

Harmful Algal Blooms (HABs) can become poisonous to water and suffocate organisms underneath

Cytotoxins

Eutrophying pollutants reach marine waters
-HABs –> brown and red ties
-Karenia Brevis –> potent toxin

Question 10

Sulfur Cycle

Answer 10

Essential component in proteins, vitamins and hormones

-in rocks or buried deep in ocean sediments

Question 11

Sulfur Cycle

Steps

Answer 11

1. Sulfur released from rocks or geological activity
2. Converted into sulfate as it reacts w the air
3. sulfate reducing bacteria convert sulfate -> sulfide
4. Used by plants -> animals -> up the food chain