nutrient cycling

Question 1

what are autotrophic organisms?

Answer 1

make their own food using solar energy or chemical energy

Question 2

what is the nitrogen cycle?

Answer 2

1. nitrogen in atmosphere (N2) is fixed in the soil by bacteria
2. N2 is converted to ammonium
3. ammonium undergoes nitrification by bacteria
4. ammonium becomes nitrites (NO2-)
5. nitrifying bacteria transforms nitrites into nitrates (NO3-)
6. nitrates are assimilated in plants to create amino/nucleic acids or they undergo denitrification (by bacteria) and go back in the atmosphere as N2
7. animals consume those plants
8. both plants and animals die and become nitrogen-containing organic compounds
9. decomposers do ammonification to create ammonium

Question 3

what is the Haber-Bosch process?

Answer 3

take N2 and turn it into ammonia that acts as a fertilizer

Question 4

what is Liebig’s Law of the Minimum?

Answer 4

biological growth is controled by the availability of the scarcest resource (limiting factor)

Question 5

what is are the two most common limiting factors in terrestrial systems?

Answer 5

water (stops photosynthesis) + nitrogen

Question 6

what is often the limiting factor in lakes?

Answer 6

phosphorus