All Flashcards
What are the steps of nitrogen fixation?
Atmospheric N2 converted to ammonia (NH3) or nitrate (NO3) by biotic (bacteria) or abiotic (lightning) processes.
What are the steps of nitrification?
Ammonia (NH3) converted to nitrite (NO2-) and then to nitrate (NO3-) by bacteria.
What are the steps of mineralization?
Decomposers break down dead organisms, converting organic nitrogen to ammonium (NH4+).
What are the steps of denitrification?
Nitrate (NO3-) converted back into nitrogen gas (N2) and nitrous oxide (N2O) by specialized bacteria.
What are the environmental consequences of fertilizer overuse?
Eutrophication (algal blooms, oxygen depletion) and reduced species richness.
How does excess nitrogen runoff affect aquatic ecosystems?
Leads to algal blooms, which deplete oxygen and harm aquatic life (eutrophication).
What is the effect of fossil fuel combustion on the nitrogen cycle?
Can convert N2 directly into NO3, contributing to atmospheric deposition and acid rain.
Why is nitrogen important for life?
It's a key component of proteins, DNA, and other vital biomolecules, essential for all living things.
What makes nitrogen a limiting nutrient?
It's essential for life but often in short supply, restricting growth and productivity.
What role do bacteria play in the nitrogen cycle?
Bacteria are involved in nitrogen fixation, nitrification, and denitrification; decomposers (some bacteria) perform mineralization.
Why is nitrogen fixation important?
It converts atmospheric nitrogen into forms usable by plants and other organisms.
Why is denitrification important?
It returns nitrogen to the atmosphere, completing the cycle and preventing excess nitrogen accumulation.
How do plants obtain nitrogen?
Plants absorb usable nitrogen (mostly nitrate) through their roots and assimilate it into their tissues.
What is the role of decomposers in the nitrogen cycle?
Decomposers break down dead organisms and waste, converting organic nitrogen back into inorganic ammonium.
What is the main reservoir of nitrogen?
The atmosphere, which is composed of approximately 78% nitrogen gas (N2).
What is the role of assimilation in the nitrogen cycle?
It's the process where plants incorporate nitrogen into their tissues, forming proteins and other biomolecules.
Why is the nitrogen cycle important for maintaining ecosystem health?
It ensures the continuous supply of nitrogen, a crucial element for plant growth and overall ecosystem productivity.