Mod 4+5: Ecological Cycles

biogeochemical cycle

the movements of matter within and between ecosystems involving cycles of biological, geological, and chemical processes

resevoirs

the components of the biogeochemical cycles that contain the matter, including air, water, and organisms

carbon cycle

the movement of carbon around the biosphere among reservoir sources and sinks

aerobic respiration

the process by which cells convert glucose and oxygen into energy, carbon dioxide, and water

steady state

when a system’s inputs equal outputs, so that the system is not changing over time

greenhouse gases

gases in Earth’s atmosphere that trap heat near the surface

global warming

the increase in global temperatures due to humans producing more greenhouse gases

limiting nutrient

a nutrient required for the growth of an organism but available in a lower quantity than other nutrients

nitrogen cycle

the movement of nitrogen around the biosphere among reservoir sources and sinks

nitrogen fixation

the process that converts nitrogen gas in the atmosphere (N₂) into forms of nitrogen that plants and algae can use

nitrification

the conversion of ammonia (NH₄⁺) into nitrite (NO₂^-) and then into nitrate (NO₃^-)

assimilation

a process by which plants and algae incorporate nitrogen into their tissues

mineralization

the process by which fungal and bacterial decomposers break down the organic matter found in dead bodies and waste products and convert these organic compounds back into inorganic compounds, such as inorganic ammonium (NH₄⁺). (also known as ammonification)

denitrification

the conversion of nitrate (NO₃^-) in a series of steps into the gases nitrous oxide (N₂O) and, eventually, nitrogen gas (N₂), which is emitted into the atmosphere

anaerobic

an environment that lacks oxygen

aerobic

an environment with abundant oxygen

leaching

a process in which dissolved molecules are transported through the soil via groundwater

phosphorus cycle

the movement of phosphorus around the biosphere among reservoir sources and sinks

algal bloom

a rapid increase in the algal population of a waterway

hypoxic

low in oxygen

dead zone

when oxygen concentrations become so lo that it kills fish and other aquatic animals

hydrologic cycle

the movement of water around the biosphere among reservoir sources and sinks

transpiration

the release of water from leaves into the atmosphere during photosynthesis

evapotranspiration

the combined amount of evaporation and transpiration

runoff

water that moves across the land surface and into streams and rivers