Topic 2: Nutrient Cycles

Question 1

IMPORTANCE OF DECOMPOSERS

• All organisms contain C, N, P and Ca
• When organisms die, Decomposers are able to recycle these elements back into the community
• The Decomposers release the trapped inorganic elements back into the soil/air to be taken up by producers
• Matter is therefore recycled through ecosystems

Answer 1

THE CARBON CYCLE

• We are carbon based, so carbon is important for carbohydrates, proteins, lipids and nucleic acid
• Consumers release carbon into the atmosphere as CO2 through the process of respiration
• The CO2 is taken up by plants for photosynthesis and stored in plant tissues, it is then taken up by consumers, who feed on plants
• When organisms die, Decomposers breakdown the dead material, taking in carbon and releasing CO2 into the atmosphere
• DIAGRAM*

Question 2

NITROGEN CYCLE

• Nitrogen is important for proteins and nucleic acid (ATP), it is also the most common element in the atmosphere
• Many bacteria are able to convert atmospheric nitrogen to ammonia which can then be converted to nitrates in the soil which are taken up by plants and then ingested by consumers
• Dead organisms are decomposed by bacteria to also produce ammonia which can be converted back to nitrates
• Many bacteria can act opposite to this, taking nitrates and releasing atmospheric nitrogen to complete the cycle
• DIAGRAM*

Answer 2

PHOSPHORUS CYCLE

• Important for nucleic acids (DNA/RNA), phospholipid membranes and ATP/ADP
• Phosphate gets eroded from rocks and washed into streams and soil
• Plants can the absorb the phosphorus as phosphate ions and consumers can ingest the phosphate from plants
• Mycorrhiza (fungi) is in close association with the roots of many plants as it allow for greater uptake of this element
• Decomposers can release the phosphate back into the soil from dead material
• DIAGRAM*