Lecture Eight- Biogeochemical cycles II Flashcards
Draw a diagram of the carbon cycle.
What are the reservoirs, fluxes and energy sources in the carbon cycle?
Reservoirs:
Atmospheric CO2.
Oceanic carbon.
Biotic carbon.
Soils and sedimnts.
Fossil fuels.
Sedimentary rock.
Fluxes:
Photosynthesis and chemeosynthesis.
Respiration (consumption and decomposition).
Sedimentation.
Uplift and erosion.
Dissolution.
Energy:
Solar energy (photosynthesis).
Chemial energy (chemeosynthesis).
Consumers and decomposers get their energy by oxidising organic carbon (cellular respiration).
How does inductrial N fixation interact with the C cycle?
More nitrogen fixation increases photosynthesis.
The Harber/Bosch process:
Draw a diagram of the N cycle.
What are the reservoirs, fluxes and energy sources in the nitrogen cycle?
Reservoirs:
Atmospheric (n2).
Organic N.
Soils.
Ammonia.
Nitrate (NO3-).
Nitrite (NO2).
Nitrous oxide.
Fluxes:
Nitrogen fixation - lightning, biological and inductrial (harber/bosch).
Uptake or assimilation.
Decomposition.
Mineralization.
Energy:
Electricity (lightning).
Solar energy (biological).
Petroleum (inductrial).
Nitrification and denitrification are ways that bacteria harvest energy.
Define decomposition and mineralization.
Decomposition: Chemical breakdown of an organic compound into simpler compounds (susally by microorganisms).
Mineralization: Conversion of an element from an organic to an inorganic form as a result of microbially mediated decomposition processes.
Define fixation and uptake.
Fixation: Atmospheric N is converted (fixed) to mineralized N by bacteria or lightning.
Uptake: Conversion of mineralized N to organic N by plants - incorporation of the N in nitrate or ammonium into amino acids, nucleic acids.
What is the consequence of industrial nitrogen fixation?
It has doubled the natural rate of N fixation on Earth.
Depleated soils of other nutrients, as plants are growing more quickly and depleating the soils of other nutrients.
Reduced the biological diversity, as some plants can grow rapidly with the increased N, but some cannot and are therefore out competed.
Increased concentration of nitrous oxide in the atmoshere.
What are rhizobia?
Rhizobia are a nitrogen-fixing bacterium that is common in the soil, especially in the root nodules of leguminous plants.
Draw a diagram of the sulfur cycle.
What are the reservoirs, fluxes and energy sources of the sulfur cycle.
Reservoirs:
Soil.
Plants.
Ocean.
Atmosphere.
Fossil fules.
Fluxes:
Industrial.
Atmospheric.
Biotic.
Sea.
Volcanoes.
Erosion.
Energy:
Industrial.
Coal.
Engines.
Volcanoes.
How are humans impacting the sulfur cycle?
Industrial sulfur dioxide production - burning coal and the internal combusion engine.
Sulfur dioxide:
Precipitate onto surfaces where it can be oxidezed to fulfate in the soil.
Oxidized to fulfate in the atmosphere as H2SO4 leading to acid rain.
How can the sulfur cycle be observed?
Winogradsky cycle:
Measuring cyliner containing freshwrer (or marine) sediments and cellulose power.
When incubated:
Cellulose acts as a C source for the system.
Various bacterial groups appear in distinct regions of the column, depending on their oxygen requirements.
