APES Unit 1 Terms

Cultural eutrophication

When excess nutrients (often from fertilizers or sewage) enter a body of water due to human activity, causing algal blooms, oxygen depletion, and harm to aquatic life.

Primary consumers

Organisms that eat producers (plants or algae); also called herbivores.

Secondary consumers

Organisms that eat primary consumers; usually carnivores or omnivores.

Tertiary consumers

Predators that feed on secondary consumers at the top of the food chain.

Herbivores

Animals that eat plants or other producers only.

Carnivores

Animals that eat other animals only.

Omnivores

Animals that eat both plants and animals.

Decomposers

Break down dead organisms into simpler substances (e.g., fungi, bacteria).

Detritivores

Feed on dead matter and waste (e.g., earthworms, crabs).

Biomass

The total mass of living matter in a given area or trophic level.

Heterotroph

An organism that must consume other organisms for energy (consumers).

Autotroph

An organism that makes its own food, usually through photosynthesis or chemosynthesis (producers).

Producers

Autotrophs at the base of food chains that capture energy to make organic molecules.

Biosphere

All parts of Earth where life exists, including land, water, and atmosphere.

Hydrosphere

All of Earth's water, in liquid, ice, or vapor form.

Geosphere

Earth's solid parts: rocks, soil, and landforms.

Atmosphere

The layers of gases surrounding Earth.

Natural capital

Earth's stock of natural resources and ecosystem services that provide value to humans.

Pelagic zone

Open ocean area away from the coast and sea floor.

Benthos

Organisms that live on or in the ocean floor.

Nekton

Strong-swimming aquatic animals such as fish, whales, and squid.

Phytoplankton

Microscopic photosynthetic organisms in water, base of aquatic food chains.

Zooplankton

Tiny floating animals or protozoans that feed on phytoplankton.

Estuary

Area where freshwater from rivers mixes with saltwater from the ocean, high in productivity.

Bays

Coastal water bodies partially enclosed by land, often connected to the ocean.

Inlet marshes

Wetlands along tidal inlets where saltwater and freshwater mix.

Coastal wetland

Land along coasts flooded by saltwater or brackish water (e.g., mangroves, marshes).

Delta

Landform at a river mouth where sediments are deposited into an ocean or lake.

Intertidal zone

Coastal area between high and low tide, alternately submerged and exposed.

Runoff

Water that flows over land into rivers, lakes, or oceans, often carrying pollutants.

Watershed

The land area that drains into a particular river, lake, or body of water.

Turbidity

The cloudiness of water caused by suspended sediments or particles.

Upwelling

The upward movement of cold, nutrient-rich water from the deep ocean, supporting high productivity.

Oligotrophic lake

A nutrient-poor, clear-water lake with low productivity.

Mesotrophic lake

A moderately nutrient-rich lake with medium productivity.

Eutrophic lake

A nutrient-rich lake with high productivity and often low oxygen levels.

Tragedy of the commons

Overuse of shared resources because individuals act in their own self-interest.

Sustainable yield

The maximum rate at which a resource can be used without depleting it long-term.