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.
Why is nitrogen important for living things?
Key component of proteins, DNA, and other vital biomolecules.
What role do bacteria play in the nitrogen cycle?
Bacteria perform nitrogen fixation, nitrification, and denitrification.
Why is nitrogen often a limiting nutrient?
It is essential but often in short supply in the environment.
What is the main form of nitrogen in the atmosphere?
Nitrogen gas (N2), which is unusable by most organisms.
How do plants obtain nitrogen?
By absorbing usable nitrogen (mostly nitrate) through their roots.
What is the role of decomposers in the nitrogen cycle?
They break down dead organisms and waste, converting organic nitrogen to ammonium.
How does fertilizer overuse affect species richness?
Plants that need more nitrogen outcompete others, decreasing the variety of species.
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.