Bellringer 1. Name 6 biomes, including the one you live in. 2. Describe the characteristics of each. 3. Name 2 animals and 2 plants for each biome.

Freshwater Ecosystems Aquatic Ecosystems Chapter 7 p

Determining Organisms Salinity = the amount of dissolved salts the water contains Salinity = the amount of dissolved salts the water contains Two Divisions of Aquatic Ecosystems: Two Divisions of Aquatic Ecosystems: Freshwater – lakes, ponds, rivers, streams, wetlands = land periodically underwater Freshwater – lakes, ponds, rivers, streams, wetlands = land periodically underwater Marine – marshes, swamps, coral reefs, oceans Marine – marshes, swamps, coral reefs, oceans

Factors Affecting Variety of Organisms Temperature Temperature Sunlight Sunlight Oxygen Oxygen Nutrients Nutrients

Aquatic Organisms Plankton = organisms that float near the surface of the water Plankton = organisms that float near the surface of the water Phytoplankton (microscopic plants) Phytoplankton (microscopic plants) Zooplankton (microscopic animals) Zooplankton (microscopic animals) Nekton = free-swimming organisms (fish, turtles, whales) Nekton = free-swimming organisms (fish, turtles, whales)

Benthos = bottom-dwelling organisms (mussels, worms, barnacles) Benthos = bottom-dwelling organisms (mussels, worms, barnacles) Live attached to hard surfaces Live attached to hard surfaces Decomposers – organisms that break down dead organisms Decomposers – organisms that break down dead organisms

Lakes and Ponds Form naturally where groundwater reaches the Earth’s surface Form naturally where groundwater reaches the Earth’s surface Artificially created by beavers (damming rivers) and humans (damming rivers and streams for power, irrigation, water storage, and recreation) Artificially created by beavers (damming rivers) and humans (damming rivers and streams for power, irrigation, water storage, and recreation)

Lake Zones

Life in a Lake – Littoral Zone Nutrient-rich zone near the shore = diverse and abundant life Nutrient-rich zone near the shore = diverse and abundant life Cattails, pond lilies Cattails, pond lilies Life present depends on amount of available sunlight Life present depends on amount of available sunlight Photosynthesizing plants Photosynthesizing plants

Life in a Lake – Benthic Zone Too little light for photosynthesis Too little light for photosynthesis Bacteria help decompose dead plants and animals that drift down from above Bacteria help decompose dead plants and animals that drift down from above Fish adapted to environment live here Fish adapted to environment live here Dead and decaying organisms reach benthic zone = the bottom of a pond or lake inhabited by decomposers, insect larvae, and clams Dead and decaying organisms reach benthic zone = the bottom of a pond or lake inhabited by decomposers, insect larvae, and clams

Special Adaptations for Survival Water beetles – hairs under bodies to trap surface air to breathe during food dives Water beetles – hairs under bodies to trap surface air to breathe during food dives Catfish – whiskers help sense food while swimming over dark lake bottoms Catfish – whiskers help sense food while swimming over dark lake bottoms Amphibians – burrow into littoral mud to avoid freezing temperatures when lake partially freezes Amphibians – burrow into littoral mud to avoid freezing temperatures when lake partially freezes

How Nutrients Affect Lakes Eutrophication = an increase in the amount of nutrients in an aquatic ecosystem Eutrophication = an increase in the amount of nutrients in an aquatic ecosystem Figure 4: a lake that has a large amount of plant growth due to nutrients (eutrophic lake) Figure 4: a lake that has a large amount of plant growth due to nutrients (eutrophic lake) Increase in number of bacteria feeding on decaying organisms Increase in number of bacteria feeding on decaying organisms

Reduction in oxygen = killing of oxygen-loving organisms Reduction in oxygen = killing of oxygen-loving organisms Occurs naturally over time. However, can be accelerated by runoff (precipitation carrying serwage, fertilizers, or animal wastes) Occurs naturally over time. However, can be accelerated by runoff (precipitation carrying serwage, fertilizers, or animal wastes)

Eutrophication

Freshwater Wetlands Areas of land that are covered with fresh water for at least part of the year Areas of land that are covered with fresh water for at least part of the year Marshes – nonwoody plants (cattails) Marshes – nonwoody plants (cattails) Swamps – woody plants (trees and shrubs) Swamps – woody plants (trees and shrubs)

Marshes

Marshes Most located in southeastern U.S. Most located in southeastern U.S. Florida Everglades is largest Florida Everglades is largest occur on low, flat lands and have little water movement occur on low, flat lands and have little water movement Wetland that contains nonwoody plants Wetland that contains nonwoody plants Benthic zones are nutrient rich and contain plants, numerous types of decomposers, and scavengers Benthic zones are nutrient rich and contain plants, numerous types of decomposers, and scavengers

Types of Marshes Brackish marshes Brackish marshes Slightly salty water Slightly salty water Salt marshes Salt marshes Saltier water Saltier water

Swamps Occur on flat, poorly drained land, often near streams Occur on flat, poorly drained land, often near streams Woody shrubs or water-loving trees Woody shrubs or water-loving trees mangrove swamps – warm climates near the ocean (salty water) mangrove swamps – warm climates near the ocean (salty water) Freshwater swamps – ideal for many amphibians (frogs and salamanders) b/c of continuously moist environment Freshwater swamps – ideal for many amphibians (frogs and salamanders) b/c of continuously moist environment American alligator – dominant predator American alligator – dominant predator

Human Impact on Wetlands Used to be thought as wastelands ideal for breeding insects Used to be thought as wastelands ideal for breeding insects As result, many drained, filled and cleared for farms, residential or commercial development As result, many drained, filled and cleared for farms, residential or commercial development Law and federal government protect many wetlands and destruction is prohibited by many states Law and federal government protect many wetlands and destruction is prohibited by many states

Rivers Many originate from snow melting in mountains Many originate from snow melting in mountains At headwaters (beginning) water is cold, full of oxygen, and runs swiftly through a shallow riverbed At headwaters (beginning) water is cold, full of oxygen, and runs swiftly through a shallow riverbed Further down, river broadens, warms, is slower and decreases in oxygen concentration Further down, river broadens, warms, is slower and decreases in oxygen concentration Runoff affects growth and health of organisms in river further down Runoff affects growth and health of organisms in river further down

Life in a River Trout and minnows are adapted to cold, oxygen-rich headwaters and strong, swift current Trout and minnows are adapted to cold, oxygen-rich headwaters and strong, swift current Plankton float further downstream in warmer, calmer water Plankton float further downstream in warmer, calmer water

Rivers in Danger Used by industries for manufacturing processes and receptacles for waste Used by industries for manufacturing processes and receptacles for waste Practice of using for waste has polluted rivers with toxins, killing organisms and making river fish inedible Practice of using for waste has polluted rivers with toxins, killing organisms and making river fish inedible Runoff from lands puts pesticides and poisons into rivers and coats riverbeds with toxic sediments Runoff from lands puts pesticides and poisons into rivers and coats riverbeds with toxic sediments

Danger!!