Section 3: Aquatic Ecosystems Aquatic ecosystems are grouped based on abiotic factors such as water flow, depth, distance from shore, salinity, and latitude. K What I Know W What I Want to Find Out L What I Learned

Essential Questions What are the major abiotic factors that determine the aquatic ecosystems? What are transitional aquatic ecosystems and why are they important? What are the zones of marine ecosystems? Copyright © McGraw-Hill Education Aquatic Ecosystems

Vocabulary Review New continued New salinity wetlands estuary sediment littoral zone limnetic zone plankton profundal zone New continued wetlands estuary intertidal zone photic zone aphotic zone benthic zone abyssal zone Aquatic Ecosystems Copyright © McGraw-Hill Education

The Water on Earth Aquatic environments are divided into freshwater and marine ecosystems. Only about 2.5 percent of the water on Earth is freshwater. Copyright © McGraw-Hill Education Aquatic Ecosystems

Freshwater Ecosystems Rivers and streams Water in rivers and streams flow in one direction. The slope of the landscape determines the direction and speed of the water. Sediment is the material that is deposited by water, wind, or glaciers. Copyright © McGraw-Hill Education Aquatic Ecosystems

Freshwater Ecosystems Rivers and streams Interactions between land and water result in differences in erosion, nutrient availability, and species composition and diversity along the course of the water. Fast moving water: less sediment and organic matter; fewer species Slow moving water: sediment is deposited as mud, silt, and sand; supports a diversity of plant and animal species Copyright © McGraw-Hill Education Aquatic Ecosystems

Freshwater Ecosystems Lakes and ponds An inland body of standing water is called a lake or pond. The temperature of lakes and ponds varies depending on the season. Turnover in lake water circulates nutrients and oxygen between water depths Copyright © McGraw-Hill Education Aquatic Ecosystems

Freshwater Ecosystems Lakes and ponds Lakes and ponds are divided into three zones based on the amount of sunlight that penetrates the water. The littoral zone is closest to shore, shallow, and sunlight reaches the bottom. The littoral zone is a highly productive area, with numerous producers. Copyright © McGraw-Hill Education Aquatic Ecosystems

Freshwater Ecosystems Lakes and ponds The limnetic zone is an open water area that is well lit. Production is dominated by phytoplankton, free-floating autotrophs Home to many freshwater fish Copyright © McGraw-Hill Education Aquatic Ecosystems

Freshwater Ecosystems Lakes and ponds The profundal zone is the deepest part of a lake or pond. Little light penetrates through the limnetic layer Colder and lower in oxygen Copyright © McGraw-Hill Education Aquatic Ecosystems

Transitional Aquatic Ecosystems Wetlands Areas of land such as marshes, swamps, and bogs that are saturated with water and that support aquatic plants are called wetlands. Wetlands have high levels of species diversity. Copyright © McGraw-Hill Education Aquatic Ecosystems

Transitional Aquatic Ecosystems Estuaries An estuary is where freshwater from a stream or river meets saltwater from the ocean. Estuaries can support a variety of habitats, such as mangrove forests or salt marshes. Copyright © McGraw-Hill Education Aquatic Ecosystems

Marine Ecosystems Intertidal zone The intertidal zone is a narrow band where the ocean meets land. Organisms must adapt to daily changes in tides and wave action. The intertidal zone is further divided into vertical zones. Copyright © McGraw-Hill Education Aquatic Ecosystems

Marine Ecosystems Open ocean ecosystems The open ocean is divided into three zones: pelagic, abyssal, and benthic. The pelagic zone is further divided into two zones The photic zone is shallow enough that sunlight is able to penetrate. The aphotic zone is an area that sunlight is unable to penetrate. Copyright © McGraw-Hill Education Aquatic Ecosystems

Marine Ecosystems Open ocean ecosystems The benthic zone is the area along the ocean floor. In shallow areas, the benthic zone receives sunlight, as depth increases, light and temperature decrease. Copyright © McGraw-Hill Education Aquatic Ecosystems

Marine Ecosystems Open ocean ecosystems The deepest region of the ocean is called the abyssal zone. Water is very cold, and there is no light penetration Organisms depend on food materials that sink from the surface Copyright © McGraw-Hill Education Aquatic Ecosystems

Marine Ecosystems Coastal ocean and coral reefs Coral reefs are one of the most diverse ecosystems on Earth. Widely distributed in warm shallow marine waters Copyright © McGraw-Hill Education Aquatic Ecosystems

Communities and Biomes Virtual Lab Aquatic Ecosystems Copyright © McGraw-Hill Education

Review Essential Questions Vocabulary What are the major abiotic factors that determine the aquatic ecosystems? What are transitional aquatic ecosystems and why are they important? What are the zones of marine ecosystems? Vocabulary sediment littoral zone limnetic zone plankton profundal zone wetlands estuary intertidal zone photic zone aphotic zone benthic zone abyssal zone Aquatic Ecosystems Copyright © McGraw-Hill Education