APES Module 3-4

Freshwater Biomes

Categorized as streams and rivers, lakes and ponds, or freshwater wetlands.

Littoral Zone

The shallow zone of soil and water in lakes and ponds near the shore where most algae and emergent plants such as cattails grow.

Limnetic Zone

A zone of open water in lakes and ponds as deep as the sunlight can penetrate.

Phytoplankton

Floating algae.

Profundal Zone

A region of water where sunlight does not reach, below the limnetic zone in very deep lakes.

Benthic Zone

The muddy bottom of a lake, pond, or ocean beneath the limnetic and profundal zones.

Oligotrophic

Describes a lake with a low level of phytoplankton due to low amounts of nutrients in the water.

Mesotrophic

Describes a lake with a moderate level of fertility.

Eutrophic

Describes a lake with a high level of fertility.

Freshwater Wetland

An aquatic biome that is submerged or saturated by water for at least part of each year, but shallow enough to support emergent vegetation.

Estuary

An area along the coast where the fresh water of rivers mixes with salt water from the ocean.

Salt Marsh

Found along the coast in temperate climates, a marsh containing nonwoody emergent vegetation.

Mangrove Swamp

A swamp that occurs along tropical and subtropical coasts, and contains salt-tolerant trees with roots submerged in water.

Intertidal Zone

The narrow band of coastline that exists between the levels of high tide and low tide.

Coral Reef

Represents Earth’s most diverse marine biome, and are found in warm, shallow waters beyond the shoreline in tropical regions.

Coral Bleaching

A phenomenon in which algae inside corals die, causing the corals to turn white.

Open Ocean

Deep-ocean water, located away from the shoreline where sunlight can no longer reach the ocean bottom.

Photic Zone

The upper layer of ocean water in the ocean that receives enough sunlight for photosynthesis.

Aphotic Zone

The upper layer of ocean water in the ocean that receives enough sunlight for photosynthesis.

Chemosynthesis

A process used by some bacteria to generate energy with methane and hydrogen sulfide.

Biogeochemical cycle

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

Reservoirs

The components of the biogeochemical cycle 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 into forms of nitrogen that plants and algae can use.

Nitrification

The conversion of ammonia into nitrite and then into nitrate.

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.

Denitrification

The conversion of nitrate in a series of steps into the gases nitrous oxide and, eventually, nitrogen gas, 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.

Tundra

A cold and treeless biome with low-growing vegetation.

Taiga

A forest biome made up primarily of coniferous evergreen trees that can tolerate cold winters and short growing seasons. Also known as boreal forest.

Temperate Rainforest

A coastal biome typified by moderate temperatures and high precipitation.

Temperate Seasonal Forest

A biome with warm summers and cold winters with over 1 m (39 inches) of annual precipitation.

Shrubland

A biome characterized by hot, dry summers and mild, rainy winters. Also known as woodland.

Temperate Grassland

A biome characterized by cold, harsh winters, and hot, dry summers. Also known as cold desert.

Tropical Rainforest

A warm and wet biome found between 20° N and 20°S of the equator, with little seasonal temperature variation and high precipitation.

Savanna

A biome marked by warm temperatures and distinct wet and dry seasons. Also known as tropical seasonal forest.

Hot Desert

A biome located at roughly 30° N and 30° S, and characterized by hot temperatures, extremely dry conditions, and sparse vegetation.