APES Unit 1.3 Aquatic Biomes

Biome

A region defined by its average temperature and precipitation.

Biome Adaptations

Plant and animal species evolve traits to survive the specific temperature and precipitation of their biome.

Aquatic Biome

Biome defined by salinity, depth, and water flow instead of temperature/precipitation.

Salinity

Measure of dissolved salts in water (ppt)

Freshwater Salinity

Less than 0.5 ppt.

Brackish Salinity

Between 0.5 and 17 ppt.

Saltwater Salinity

Around 35 ppt.

Water Flow

Movement of water that increases oxygen diffusion and transports sediments and nutrients.

Energy Flow

Movement of energy through an ecosystem from producers → consumers → decomposers.

Depth

Measurement from water’s surface downward

Temperature (Aquatic)

Determines species distribution based on heat and kinetic energy levels.

Mangrove Adaptation

Mangrove plants pump excess salt out through specialized membranes or pores.

Freshwater Biomes

Streams, rivers, ponds, and lakes

Marine Biomes

Oceans, coral reefs, marshes, estuaries

Resource Distribution in Marine Biomes

Varies due to salinity, depth, turbidity, nutrients, and temperature.

River

Flowing freshwater system starting at high elevation and draining into larger bodies of water.

Lake Littoral Zone

Shallow near-shore area where sunlight reaches the bottom and plants grow.

Lake Limnetic Zone

Well-lit open water where photosynthesis occurs but plants cannot root.

Lake Profundal Zone

Deep, dark water with low oxygen

Benthic Zone

Bottom layer of a body of water

Benthos

Organisms living on or in the bottom sediments.

Littoral vs Limnetic

Shallow near shore and other is deeper water further from shore

Wetland

Area where water covers soil for part or all of the year.

Wetland Benefits

Filter pollutants, reduce flooding, and provide biodiversity habitats.

Estuary

Partially enclosed area where freshwater mixes with saltwater, creating brackish, nutrient-rich habitats.

Brackish Water

Mix of fresh and salt water found in estuaries.

Watershed

Land area where all water drains to a common outlet like a river or ocean.

Estuary Productivity

High productivity due to nutrient transport, tidal mixing, and diverse plant life.

Estuary Variable Factors

Temperature, salinity, and light levels constantly change.

Estuary Specialists

Species adapted to narrow environmental conditions.

Estuary Generalists

Species able to tolerate wide environmental variation.

Estuary Salinity Factors

Determined by precipitation and the hydrologic cycle.

Hydrologic Cycle

Continuous movement of water on, above, and below Earth’s surface.

Freshwater Wetlands

Saturated land like marshes and swamps that support unique plant and animal life.

Wetland Water Purification

Wetlands trap sediments, absorb nutrients, and break down pollutants.

Intertidal Zone

Coastal area between high and low tide with shifting salinity, temperature, and moisture.

Tide Pool

Depressions in rock that hold seawater and form stable microhabitats.

Wave Action

Movement of waves shaping coastlines through erosion, transport, and deposition.

Deposition

Process where materials settle from water or air onto Earth’s surface.

Coral Reef

Biodiverse marine ecosystem built by coral polyps in warm, shallow, clear water.

Coral Polyps

Tiny animals that secrete calcium carbonate to build reef structures.

Zooxanthellae

Symbiotic algae living in coral that provide food through photosynthesis.

Open Ocean

Largest marine biome with deep saltwater beyond the continental shelf.

Photic Zone

Sunlit top layer of ocean where photosynthesis occurs (top ~200 m).

Aphotic Zone

Deep ocean region with no sunlight and no photosynthesis.

Upwelling

Movement of cold, nutrient-rich water to the surface, increasing productivity.

Drinking Water Sources

Rivers, lakes, and freshwater wetlands.

Marine Biome Definition

Saltwater ecosystem including oceans, coral reefs, and coastal zones covering 70% of Earth.

Estuary Biome Definition

Where freshwater mixes with saltwater

Freshwater Wetland Definition

Land saturated with water part or all year, supporting marshes and swamps.

Wetland Plant Adaptations

Air spaces, flexible stems, and shallow roots for oxygen and stability.

Intertidal Zone Definition

Area covered at high tide and exposed at low tide with extreme environmental shifts.

Intertidal Organism Adaptations

Holding to rocks, closing shells, tolerating temp and salinity changes.