Biogeochemical Cycles

Question 1

What is the biosphere?

Answer 1

The biosphere is defined as the layer around the earth containing all living organisms.

Question 2

What is lithosphere?

Answer 2

Solid layer of our planet so land.

Question 3

what is the hydrosphere?

Answer 3

liquid layer, oceans, lakes, rivers and puddles.

Question 4

carbon is the basic element in which complex molecules?

Answer 4

like protein, lipids (fats) and
carbohydrates.

Question 5

What is photosynthesis?

Answer 5

Photosynthesis: Plants use radiant energy to capture the carbon dioxide found in the
atmosphere or in water. The carbon dioxide is changed into oxygen which plants use for
energy to grow and develop.

Question 6

What is the steps in the carbon cycle?

Answer 6

1.Photosynthesis:
2. Ingestion:
3. Respiration:
4. Decomposition of waste:
6. Shells and skeletons: s.
7. carbonate rock:
8. Volcanic eruptions:
9. Fossil fuels:

Question 7

What happens in the respiration step of the carbon cycle?

Answer 7

Respiration: Living organisms exhale and return part of the carbon they have eaten
back to the atmosphere as carbon dioxide. The unbalanced equation for respiration is as
follows:

Question 8

What happens in the carbonate rock step of the carbon cycle?

Answer 8

Carbonate rock: The calcium carbonate from shells and skeletons falls at the bottom of
the ocean and accumulates in the sediment. It then changes and forms carbonate rock.
Because of the tectonic plates on Earth, these rocks are often transported back to the
surface.

Question 9

What happens in the shells and skeleton part of the carbon cycle?

Answer 9

Shells and skeletons: Part of the carbon dioxide dissolved in water reacts with water
and calcium to become calcium carbonate. This substance makes up the shells and
skeletons of marine organisms.

Question 10

Name the nitrogen cycle steps.

Answer 10

1. Nitrogen fixation:
2. Nitrification:
3. Nitrogen absorption by plants and animals:
4. Decomposition of waste:
5. Denitrification:

Question 11

What happens in the nitrification step of the Nitrogen cycle?

Answer 11

Nitrification: Bacteria oxidize ammonium to form nitrites. Bacteria oxidize nitrites into
nitrates.

Question 12

What happens in the Denitrification step of the Nitrogen cycle?

Answer 12

Denitrification: Bacteria convert nitrates into molecular nitrogen which returns to the
atmosphere.

Question 13

What happens in the Nitrogen fixation step of the Nitrogen cycle?

Answer 13

Nitrogen fixation: Bacteria in the soil take atmospheric nitrogen and change it into
ammonia. The ammonia reacts with hydrogen to form ammonium.

Question 14

What factors effect the nitrogen cycle?

Answer 14

Factors such as temperature, humidity, and pH can affect the nitrogen cycle. Famers apply
fertilizer rich in ammonia, ammonium and nitrates to their fields which affect the nitrogen cycle.
This cycle is also affected by nitrogen being discharged in the wastewater of factories. This
excess can lead to an imbalance in soil and interfere with plant growth.

Question 15

Name the steps in the phosphate cycle.

Answer 15

1. Erosion: Wind and rain erode rocks that contain phosphorous and it ends up in the soil in the form
   of phosphates PO4
   .
2. Plants absorb the phosphates from the ground and passes it up the food chain to herbivores and
   then carnivores.
3. Animals release phosphates back into the ground through feces and urine. They are also released
   into the soil when decomposers break down organic matter.
4. Phosphates find their way to the oceans and favor the growth of plankton. Some fall to the bottom
   of the ocean and after many, many years, solidify into rock.

Question 16

What happens in the Erosion step of the phosphorus cycle?

Answer 16

Erosion: Wind and rain erode rocks that contain phosphorous and it ends up in the soil in the form
of phosphates PO4.
.