Nitrogen Cycle

Flashcards about the nitrogen cycle, including sources, sinks, reservoirs, and human impacts.

What are the sources in the nitrogen cycle?

Things or processes that release nitrogen into the atmosphere.

What are sinks in the nitrogen cycle?

Things or processes that take in increasing amounts of nitrogen.

How does the nitrogen cycle differ from the carbon cycle?

Nitrogen reservoirs generally hold nitrogen for a relatively short period, unlike carbon reservoirs like fossil fuels.

What is the biggest reservoir of nitrogen?

The atmosphere, which is about 78% nitrogen.

What form does most of the nitrogen in the atmosphere exist in?

N2 gas, which is not usable by plants or animals.

Why is nitrogen a key limiting nutrient for plants and animals?

All living things need nitrogen to make DNA and amino acids.

What is nitrogen fixation and why is it important?

The process of converting nitrogen gas from the atmosphere into biologically usable forms (ammonia or nitrate), critical for life on Earth.

Name two ways natural nitrogen fixation can occur?

By nitrogen-fixing bacteria or by lightning storms.

What role do legumes play in nitrogen fixation?

Legumes have root nodules where bacteria live and fix nitrogen for the plants in exchange for amino acids.

What is synthetic nitrogen fixation?

Humans combust fossil fuels to fix nitrogen gas from the atmosphere into nitrates for synthetic fertilizers.

What is assimilation in the nitrogen cycle?

The process of plants and animals taking in nitrogen and incorporating it into their bodies.

How do plants and animals assimilate nitrogen?

Plants take in nitrates or ammonia from the soil, while animals eat plants or other animals that have eaten plants.

What is ammonification?

Soil bacteria, microbes, and decomposers converting waste and dead biomass back into ammonia that returns to the soil.

What is nitrification?

The process where ammonium is converted into nitrite and then into nitrate by soil bacteria.

What is denitrification?

The conversion of soil nitrogen (nitrate) back into a gas form (nitrous oxide) by bacteria, which is released into the atmosphere.

How do humans impact the climate through the nitrogen cycle?

By the release of nitrous oxide, a greenhouse gas, from agricultural soils.

What is ammonia volatilization?

Excess fertilizer leading to ammonia gas entering the atmosphere, causing acid precipitation and respiratory issues.

What are leaching and eutrophication?

Leaching is when rainwater carries nitrates out of the soil, leading to agricultural runoff entering water bodies and causing eutrophication (aggressive algae growth).