Nitrogen and Phosphorus Cycles
True or False: Organisms can readily use nitrogen gas.
False - organisms cannot use nitrogen gas - the nitrogen has to be in a more usable form
NH3
ammonia
What nitrogen compound is toxic to plants?
ammonia
the process that happens as organisms are decomposed - releasing ammonia or ammonium ions back into the soil
ammonification
NH4+
ammonium
a nitrogen compound that only some plants can use
ammonium
process where plants use nitrogen to build proteins, DNA and chlorophyll
assimilation
process by which bacteria convert nitrate back into nitrogen gas
denitrification
what are 4 ways phosphorus is released back into the environment?
during decomposition, weathering of apatite rocks and bird droppings (guano), erosion, leaching
What happens to ammonia automatically in the soil as it reacts with water?
it converts into ammonium
NO3
nitrate
nitrogen compound that most plants use
nitrate
the two-part process by which bacteria convert ammonia into nitrite and then nitrate
nitrification
NO2
nitrite
process by which bacteria convert nitrogen gas into ammonia
nitrogen fixation
N2
nitrogen gas
PO4
phosphate salt
What are two things that make the phosphorus cycle different from the other cycles?
phosphorus is not found in a gaseous state and therefore the atmosphere doesn't play a role, it is the slowest cycle
how are phosphate salts absorbed and transferred?
plants take it in from the soil / water, animals eat the plants
What is the largest reservoir of nitrogen?
the atmosphere