Material Cycles

These flashcards cover key concepts related to material cycles, including biogeochemical cycles, the hydrologic cycle, carbon cycle, nitrogen cycle, and phosphorus cycle.

What is the difference between material cycles and energy movement in ecosystems?

Energy moves linearly through an ecosystem, while materials cycle back and forth.

What are the four major biogeochemical cycles?

Global cycles: Hydrologic, Carbon, Nitrogen; Local cycle: Phosphorous.

What drives the hydrologic cycle?

Solar energy drives the hydrologic cycle through evaporation and condensation.

What is transpiration?

Transpiration is the process by which plants release water into the atmosphere.

What is the carbon cycle?

The movement of carbon from the atmosphere into organisms and back again.

What are carbon sinks?

Parts of the carbon cycle that remove carbon dioxide from the atmosphere.

What human activity contributes to excess carbon dioxide in the atmosphere?

The burning of fossil fuels.

What is nitrogen fixation?

The process by which certain bacteria convert atmospheric nitrogen (N2) into ammonia (NH3) or ammonium (NH4+).

What is the process of nitrification?

The conversion of ammonia (NH3) or ammonium (NH4+) into nitrate (NO3-) or nitrite (NO2-) by bacteria.

What is denitrification?

The process of converting nitrate (NO3-) back to nitrogen gas (N2) by anaerobic bacteria.

What is the significance of the phosphorus cycle in ecosystems?

Phosphorus is needed to make DNA, ATP, and other important biological molecules.

What is the main storehouse for phosphorus?

The earth's crust.

How is phosphorus returned to the environment?

Through waste excretion and decomposition of dead organisms.

What is eutrophication?

The enrichment of nutrients in aquatic systems that can lead to increased algae growth and reduced oxygen levels.

Why is phosphorus considered a limiting nutrient in aquatic ecosystems?

Because its availability can restrict the growth of plant and algae populations in the water.