Nutrient cycles Flashcards
(20 cards)
Nutrient cycles definition
the repeated pathway of particular nutrients or elements from the environment through one or more organisms back to the environment
e.g. carbon, nitrogen, phosphorus cycle
T or F- Living things don’t create new matter
T- they recycle nutrients from air, soil, water, other organisms and use solar energy to build and maintain themselves
T or F- Productivity of all ecosystems depends on nutrients cycling through the systems
T
What is 1 way human activity adds excess nutrients?
Artificial fertilisers running off into waterways
What is the effect of excess nutrients in waterways from fertilisers?
○ Once in water, excess nutrients encourage algae to grow- consuming dissolved oxygen in water
○ Leads to death of aquatic flora, fauna (process= eutrophication)
What is 1 way human activity decreases nutrients?
Land clearing (remove humus= key source of returning nutrients to soil)
Increases rate of nutrient leaching- process of rain ‘washing’ nutrients out of soil (loss of vegetation contributes to this)
Define nitrogen cycle
the movement of nitrogen between air, soil compounds and compounds in bodies of living organisms
Why is nitrogen essential to living organisms?
It’s used to make proteins
What % of air is nitrogen?
78%
Where do plants get nitrogen from?
Mostly from soil
What happens to excess protein (from nitrogen) in animals
Excreted as waste
What do decomposers (mainly soil bacteria) do with animal/plant waste?
Soil bacteria convert ammonium into nitrates. Some of this converts to nitrogen gas, released back into atmosphere.
Define phosphorus cycle
movement of phosphorus within and between the biosphere, hydrosphere and geosphere
Why is phosphorus important?
plays central role in transfer of energy within organisms, structure of genetic material, and composition of cell membranes, bones and teeth.
Is carbon, nitrogen, or phosphorus most essential for fertilisers?
Phosphorus
Is phosphorus a gas in the atmosphere?
No- found in Earth’s crust, especially in sedimentary rocks
How does the phosphorus cycle originate from rocks?
- As these rocks weather and erode, dissolved phosphates enter soil and travel via rivers to the ocean
- Primary producers in land and ocean absorb phosphate needed to produce organic compounds necessary for survival and growth of all organisms
T or F- Changes in ocean circulation patterns affect concentration and distribution of nutrients like phosphorus and nitrogen
T
Define carbon cycle
The processes and events involved in recycling carbon in the environment.
How does photosynthesis occur?
plants take in carbon dioxide and water, and turn it into glucose and oxygen
