Aquatic Ecosystems Ch 7 Aquatic Ecosystems Temperature sunlight

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Aquatic Ecosystems Ch. 7

Aquatic Ecosystems Ch. 7

Aquatic Ecosystems • Temperature, sunlight, oxygen, nutrients determine where organisms live • 3 groups

Aquatic Ecosystems • Temperature, sunlight, oxygen, nutrients determine where organisms live • 3 groups of organisms • Plankton- drifters, can’t swim against current – base of the food chain (phytoplankton=plants that serve as base of food, jellyfish (zooplankton) • Nekton – free swimming organisms (fish, turtles, whales) • Benthos – bottom dwellers, usually attached to hard surfaces (mussels, worms, barnacles)

Section 7 -1: Freshwater: Lakes and Ponds • Low salinity (salt) in water •

Section 7 -1: Freshwater: Lakes and Ponds • Low salinity (salt) in water • Form naturally where groundwater reaches the surface or where men or beavers dam up streams and rivers • Littoral zone – near the shore, lots of sunlight, rich in nutrients, diverse and abundant life • Benthic zone – bottom, inhabited by decomposers, insect larvae, clams • Eutrophication – an increase in the amount of nutrients in a lake • Large amount of algae and plant growth • Decomposers (bacteria) use up the oxygen and kill out other organisms • Accelerated by runoff

Freshwater: Wetlands • Most are in the SE United States • Areas of land

Freshwater: Wetlands • Most are in the SE United States • Areas of land covered with freshwater at least part of the year • Marshes – non-woody plants • Swamps – trees and shrubs

Freshwater Wetland: Environmental Functions • Act as filters by absorbing and removing pollutants from

Freshwater Wetland: Environmental Functions • Act as filters by absorbing and removing pollutants from water, improving water quality downstream • Controls flooding by absorbing overflow from rivers • Spawning area for freshwater game • Habitat for native and migratory birds

Marshes • Florida Everglades – largest wetland in US • Occur in low flat

Marshes • Florida Everglades – largest wetland in US • Occur in low flat lands with little water movement • Plants root in rich bottom sediments and stick out above water • Benthic zones are very rich in nutrients • Salinity varies – some are brakish while others can be salty

Swamps • Occur on flat, poorly drained land, often near streams • Salinity varies

Swamps • Occur on flat, poorly drained land, often near streams • Salinity varies and determines which species live there • Ideal for amphibians, birds and reptiles

Human Impact on Wetlands • Once thought of as wastelands and breeding grounds for

Human Impact on Wetlands • Once thought of as wastelands and breeding grounds for insects • Many have been drained, filled and cleared for development • Florida Everglades once covered 8 million acres but now only covers 2 • Vital functions of wetlands now recognized • Government protects many wetlands

Freshwater: Rivers • Begin at headwaters – usually snowmelt in the mountains • Water

Freshwater: Rivers • Begin at headwaters – usually snowmelt in the mountains • Water flows fast and contains a lot of oxygen and is cold • Downstream it becomes warmer, wider, and slower with more vegetation and less oxygen • Life in a river – • Near headwaters – mosses anchor to rocks, trout and minnows • Downstream – plants root into the sediment, Catfish and carp in the calmer water

Section 7 -2: Marine Ecosystems • Coastal Wetlands – covered by salt water all

Section 7 -2: Marine Ecosystems • Coastal Wetlands – covered by salt water all or part of the year • Provide habitat and nesting for birds and wildlife • Protects from flooding by absorbing excess rain • Filter out pollutants and sediments • Provide recreational areas

Estuaries • Area in which fresh water from a river mixes with salt water

Estuaries • Area in which fresh water from a river mixes with salt water from the ocean • Nutrient traps – currents cause nutrients and mineralrich mud to fall to bottom • Producers use nutrients to grow in the mud • Always receiving fresh nutrients = super productive ecosystem

Plants and animals in estuaries • Ecosystems support many organisms • Lots of sunlight

Plants and animals in estuaries • Ecosystems support many organisms • Lots of sunlight for photosynthesis • Lots of nutrients from ocean and river • Shallow water • Organisms can tolerate variations in salinity because the salt varies with the mixing of ocean water and fresh water • Plants, plankton, fish, dolphins, manatees, otters, oysters, clams and barnacles

Threats to estuaries • 6 of the world’s 10 largest cities were built on

Threats to estuaries • 6 of the world’s 10 largest cities were built on estuaries • Protected harbor, access to ocean and river • Used as solid waste landfills then building sites • Pollution from sewage, industrial waste, and agricultural runoff • Estuaries cannot cope with excessive amounts of pollution caused by dense human populations

Types of estuaries • Salt marshes – estuaries where rivers deposit mineral mud •

Types of estuaries • Salt marshes – estuaries where rivers deposit mineral mud • Supports clams, fish, aquatic birds, young shrimps, crabs • Barrier Islands: run parallel to sandy shores and protect the mainland from storms and waves • Mangrove swamps – swamps with a lot of mangrove trees in them (trees that can grow in shallow salty water) – above ground roots • Protect shoreline from erosion and damage from storms • Over 2, 000 animal species • Tropical and sub-tropical areas

 • Using the picture, list the biotic and abiotic factors in this marine

• Using the picture, list the biotic and abiotic factors in this marine ecosystem. • Explain why an estuary is such a productive ecosystem.

Coral reefs • Limestone ridges built by tiny coral animals • One of the

Coral reefs • Limestone ridges built by tiny coral animals • One of the most diverse ecosystems in terms of the kinds of life there • Found in clear, shallow tropical seas because they need warm salt water with enough light for photosynthesis • Outer layer of reef contains living coral, inner layers are skeletons • Coral animals sting their prey as they float by

Dangers to the reef • Fragile ecosystem • Can be harmed by • Water

Dangers to the reef • Fragile ecosystem • Can be harmed by • Water temp that is too hot or too cold • Muddy, polluted, or nutrient rich water (not enough light for photosynthesis) • Coral bleaching – coral turns white when algae the live in the coral leave or die • Occurring often enough will lead to death of coral • 50% of today’s reefs are in danger of destruction • Reefs grow too slowly to repair themselves from damage

Oceans • Water absorbs sunlight down to about 100 m • Most of the

Oceans • Water absorbs sunlight down to about 100 m • Most of the life is in the shallow coastal waters where sunlight reaches bottom and river nutrients wash in • Ocean surface – plankton, nekton (swimmers) • Deep ocean – no sunlight, organisms depend on food that drifts down from above –Benthos (decomposers, filter feeders)

Threats to ocean • Runoff pollution • Sewage, city wastes, industrial wastes • Overfishing,

Threats to ocean • Runoff pollution • Sewage, city wastes, industrial wastes • Overfishing, fishing methods (nets that tangle animals)

Closure • Describe the abiotic and biotic factors of the coral reef and ocean

Closure • Describe the abiotic and biotic factors of the coral reef and ocean ecosystems. Explain how these ecosystems are threatened.