Review for Nitrogen and Carbon Cycles

A comprehensive set of flashcards covering key concepts of the nitrogen and carbon cycles important for exam preparation.

What is the major building block of all known life?

Carbon

What types of compounds does carbon form?

Organic and inorganic

What increases CO2 and CH4 levels in the atmosphere?

Human activities

What is the study of the global carbon cycle closely related to?

The study of climate change

How does CO2 flow change drastically in a 24/hr period?

Day and night cycles change the amount of CO2 released.

Human activities have increased atmospheric CO2 by what percentage in the last 200 years?

50%.

How is climate change distributed in the atmosphere?

Unevenly.

Where are the higher relative temperature increases located?

High latitudes.

What are the carbon sources?

Fossil fuel combustion, cement production, and land use changes.

What are the carbon sinks and their percent correlation?

45% in atmosphere, 30% in oceans, 25% in terrestrial ecosystems.

What are the two types of carbon subcycles?

Fast and slow carbon cycles.

What processes are included in the fast carbon cycle?

Photosynthesis, respiration/decomposition, ocean/atmospheric change, burning of biomass.

What processes are included in the slow carbon cycle?

Carbon burial, rock formation, weathering and erosion, volcanic activity.

Which carbon cycle fixes atmospheric carbon as glucose?

Fast carbon cycle.

What is the biological pump in the ocean?

The process where atmospheric CO2 is taken to depths of the ocean and is fixed as organic carbon.

What type of carbon sinks to the deep ocean?

Dissolved organic carbon or particulate carbon.

What fraction of organic carbon is deposited in marine sediments?

Fraction.

What is combustion?

A chemical process where substances react rapidly with oxygen and release heat and light.

What is carbon burial?

The process where organic and inorganic carbon are deposited and preserved in sediments of the Earth's crust.

What is the primary natural source of CO2?

Volcanoes.

What is silicate weathering?

The process where dissolved CO2 forms carbonic acid and reacts with silicate rocks.

What does silicate weathering do to the atmosphere?

Cools the atmosphere.

What type of feedback loop regulates atmospheric CO2 levels?

Negative feedback loop.

What occurs to CO2 if weathering increases?

Cooling effect.

What occurs to CO2 if weathering decreases?

Warming effect.

Why is nitrogen essential for life?

It is a main element in chlorophyll, proteins, DNA, and RNA.

What type of nutrient is nitrogen and what does it control?

Limiting nutrient that controls plant and phytoplankton growth.

How does fertilizer application and deforestation affect the nitrogen cycle?

Increases reactive nitrogen in the environment.

Where is the largest pool of nitrogen located on Earth?

The atmosphere.

What is the most abundant form of nitrogen?

N2.

What about N2 chemistry makes nitrogen a limiting factor?

The triple bond costs a lot of energy to break, making it inert to most organisms.

Where is the second largest amount of nitrogen stored?

Lithosphere (rocks and sediments) as mineral-bound nitrogen.

What is the biological, chemical and physically active form of nitrogen?

Nr, reactive nitrogen.

Unlike N2, what can be used by plants and microbes?

Nr.

What are the two main types of Nr?

Organic (dissolved organic) and inorganic.

What are the organic forms of nitrogen?

Urea, amines, amino acids, proteins.

What are the inorganic forms of nitrogen?

NH3 (ammonia), NH4 (ammonium), NO3 (nitrate), NO2 (nitrite), N2O (nitrous oxide).

What are the new inputs of nitrogen?

Biological nitrogen fixation, atmospheric deposition, human inputs, Haber-Bosch process.

What are the forms of internal cycling of nitrogen?

Mineralization, immobilization, nitrification, plant N uptake/litterfall.

What are small fluxes of nitrogen compared to internal cycling in the ecosystem?

Inputs and losses.

Where does the vast majority of nitrogen that supports GPP go?

Recycled in the ecosystem.

What conditions are required for denitrification?

Low oxygen, high nitrate, and supply of organic carbon.

In what type of environment does denitrification occur?

Heterogeneous environments.