biogeochemical cycles Flashcards
what is a biogeochemical cycle?
-inter-linked processes that allow materials to be re-cycled and reused
why are biogeochemical cycles important?
-many elements have low availability to living organisms
•carbon- basic unit of organic life
•nitrogen- needed to make proteins
•phosphorus- used to make dna
where is carbon stored?
-carbon reservoir:
•atmosphere
•hydrosphere
•biosphere
•lithosphere
how does the carbon cycle show dynamic equilibrium?
-carbon moves back and forth between the atmosphere and living things (biomass)
-transfers cancel each other out, so the net effects is no change
-photosynthesis removes co2 from the atmosphere and converts it into plant leaves, stems and roots
-respiration returns co2 to the atmosphere by oxidising sugars
-photosynthesis and respiration are in balance
what are some human interferences with the carbon cycle?
-burning fossil fuels
-carbonic and acidification in oceans- leads yo ocean acidification
-deforestation + afforestation (not in equilibrium)
-anaerobic respiration environments disrupted e.g. marshlands, peat bogs
-soil- disruption through agriculture (plowing, livestock, crops)
what are some alternatives to fossil fuel use?
-solar power + other renewable energy resources
-nuclear power
how can we conserve peat bogs?
-turn land containing peat bogs into protected land/reserves - reduce human interaction with land
-preventing fires on the land (releases carbon)
how can we match afforestation to deformation?
-reducing deforestation while increasing the number of trees planted
how can we increase soil organic matter?
-use of organic fertilisers
-increase biodiversity of the plant and animal species
-encourage growth of microorganisms and decomposes
what are some human interferences of the nitrogen cycle?
-use of fertiliser in agriculture has reduced soil quality (by harming detrivores and leading to leaching of soil
-release of greenhouse gases (nitrous oxide) which impacts equilibrium
-lack of biodiversity/ less nitrogen fixing bacteria in the soil leading to use fertilisers
-haver process fixing nitrogen in ammonia, mainly to produce agricultural fertiliser
what is the phosphorus cycle?
-very different from the carbon and nitrogen cycle as the atmosphere isn’t involved
-phosphorus compounds are not very soluble and are often the limiting factor on plant growth
-especially so in deep oceans where there aren’t any rocks to release phosphates during weathering
what is the transfer process ‘root absorption’?
-plant roots absorb phosphorus to use in metabolic processes
-not effective at absorbing phosphates, so most plants have a symbiotic relationship with mycorrhizal fungi
-these have extensive networks of fungal hyphae in the soil which increase the surface
what is the transfer process ‘decomposition’?
-the breakdown of phosphorylated proteins in dead organic matter
-releases phosphates that are often made more soluble by soil microbes so they can be absorbed by plants
what is the transfer process ‘sedimentation’?
-phosphorus in organisms is hat die and become incorporated into sediments may no longer be available to other organisms such as planktonic organisms that die and sink to ocean floor
-this reduced the productivity of the surface waters of oceans because phosphorus availability is often a limiting factor
what is the transfer process ‘mountain building and weathering’?
-process that mobilise phosphorus and make it available to living organisms that are often slow
-the phosphorus in marine sediments may not become available again u til continental drift forms new mountain ranges and weathering of rocks releases the phosphates
