Structuring the biosphere: biogeography Flashcards
what processes turn atoms to life and life to atoms
atoms to life: photosynthesis
life to atoms:
respiration
in what form is carbon in plants
it is fixed by the plant into a reduced form
what two sources can energy for life come from
photosynthesis and chemosynthesis
what element is the basis of all macromolecules that form life on earth?
carbon
through which processes do dead biomass and living biomass exchange carbon
assimilation and senescence
where is nearly all CO2 sequestered
sedimentary rocks
what is the only net sink on earth for CO2
the ocean, this makes it an important control
how is the nitrogen cycle stable?
balance between processes of nitrogen fixation and denitrification
what is homeostasis
self-regulating process by which biological systems tend to maintain stability while adjusting to conditions
describe the main steps of the calcium cycle
- released from minerals by weathering
- resides mils of years in the ocean
- biomineralisation- used by organisms to form shells
- shells-> limestone, sequesters the calcium
- uplift-> calcium weathered and becomes part of soil
- passed onto plants and animals
where is sulphur released from
volcanic eruptions
how does sulphur increase the albedo
sulphur joins with aerosols to whiten the atmosphere
what is soil
a weathered rock material altered by the presence of living and decaying organisms so it can support life
what are the smallest parts of soil called
colloids
what determines soil texture
the relative proportions of different materials in the soil: clay, silt, sand, gravel particles, humus
what distinguishes soil from sediment
living organisms
what is soil fertility
the ability of soil to provide essential nutrients to plants, like phosphorus, potassium and nitrogen
describe how soil holds onto nutrients
most of components dissolved in water are cations. clay particles are anions, so they hold onto the nutrients
what factor influences the solubility of nutrients
pH, the hydrogen ion activity
provide a few examples of how humans are impacting on biogeochemical cycles
artificial fertilisers control the nitrogen cycle,
deforestation and fossil fuel burning releases sequestered carbon, production of cement,
releasing sulphur leads to acidification of rain
name 10 terrestrial biomes
tundra, boreal forest, temperate rainforest, temperate deciduous forest, tropical rainforest, tropical deciduous forest, savanna, chaparral (mediterranean), grassland, desert
name 3 aquatic biomes
marine, freshwater, transitional
