Aquatic Ecosystems

Chapter 7

Key VocabularyWETLAND- an area where land is periodically under water

PLANKTON-organisms that float near the top or surface of water, two types:phytoplankton (microscopic plants) and zooplankton (microscopic animals)

NEKTON- free swimming organisms like fish, turtles, and whales

BENTHOS- bottom dwelling organisms such as mussels, worms and barnacles

LITTORAL ZONE- area near the shore of fresh water, nutrient rich, and abundant and diverse aquatic life

BENTHIC ZONE- bottom area of a pond or lake in fresh water, includes decomposers, insect larvae and clams

EUTROPHICATION- an increase in the amount of nutrients in an aquatic ecosystem, associated with a lot of plant life

ESTUARY- an area where fresh water from a river mixes with salt water from an ocean

SALT MARSH- develop in estuaries where rivers deposit mineral rich mud

MANGROVE SWAMP-swamps located along coastal areas of tropical and subtropical zones

BARRIER ISLANDS- long, thin islands that run parallel to the shore

CORAL REEFS- limestone ridges built by coral animals called coral polyps which secrete calcium carbonate, home to many different plants and animals

Freshwater EcosystemsObjectives 1-4

1. What factors determine where an organism lives in an aquatic

ecosystem?the types of organisms that live in aquatic systems is determined by the salinity of the water- amount of dissolved salts in the water

determining factors include temp., sunlight oxygen, and nutrients

types of organisms include plankton (plant and animal), nekton ( free swimmers), and benthos ( bottom dwellers)

Freshwater Ecosystems

LAKES

PONDS

RIVERS

WETLANDS

STREAMS

2. Littoral vs. Benthic Zones

lakes and ponds are divided into different

zones

Littoral Zonesnutrient rich

near the shore

contains rooted plants underwater with leaves emerged above water, floating leaves, submerged plants, algae, and bacteria

types of organisms present depends on amount of sunlight

BENTHIC ZONE

bottom area of lake or pond consisting of decomposers, larvae of insects, and clams

Freshwater Wetlands

areas of land covered by water for part of a year

2 types: marshes that contain nonwoody plants and swamps that contain woody plants

3. Importance of Freshwater Wetlands, see table 1 pg. 1751.serve as filters or sponges, absorbing and filtering pollutants which increases water quality

2. control flooding by absorbing extra water

3. serve as feeding and spawning ground for fish

4. provide habitats for wildlife & traps carbon

6.used to produce commercial products

Marshesmost U.S marshes in southeast , Florida Everglades is the larges U.S. marsh

occur on low flat land with little water movement

nutrient rich bottom sediment good for plants

marsh types characterized by salinity (brackish vs. salt)

Swamps

occur on flat, poorly drained land, commonly near streams

woody shrubs or water loving trees

mangrove swamps (salty) and freshwater swamps

fresh provide habitat for amphibians, waterfowl, and reptiles

Human Impact on Wetlandsonce considered wastelands

many have been drained, filled or cleared for farming and residential development

protected by government b/c of importance as habitats, purifiers , and flood prevention

RIVERSmany rivers originate from snow melt from mountains

headwaters cold & full of oxygen, running swiftly

as river flows downward, it can widen, get warmer, slower, and decrease in oxygen

changes with land and climate

river location & characteristics determine life that lives there

4. RIVERS IN DANGERindustries use river water for manufacturing and for waste deposits

people have used rivers for sewage and garbage

these uses lead to pollution that kills and makes fish in edible

run off from land puts pesticides and poisons into rivers

dams also alter ecosystems

Marine Ecosystems

-Coastal Wetlands-Oceans

Coastal Wetlandsinclude estuaries and coral reefs

provide habitats and nesting areas for fish and wildlife

absorb excess rain from flooding, filter pollutants, provide recreational areas

Estuariesarea where fresh water from river mixes with salt water from ocean

include horseshoe crabs, variety of plants, dolphin, manatee, seals, oysters, barnacles ( organisms must be able to tolerate variation in salinity)

major ports are built on estuaries, why?

threats include wastes from sewage, industrial waste with toxic chemicals, and agricultural run off

5. Why is an estuary a productive ecosystem?

They constantly receive nutrients from rivers and oceans

see page 179

6. Salt water marshes vs. mangrove swamps... salt marshes are

dominated by marsh grasses and develop in estuaries, common along Gulf of Mexico & Atlantic. coast

mangrove swamps are dominated by mangrove trees and develop in tropical and subtropical areas, dominated by salt tolerant trees

Rocky and Sandy Shores

Barrier Reefs-long thin island runs parallel to shore, protect mainland and coastal wetlands

rock shores have more species, why?

Coral Reefs

live in clear, warm, shallow salt water

limestone ridges built by coral polyps

home to thousands of species of plants and animals

7. Factors that can damage coral reefs...

water that is too cold or too hot can kill coral reefs

muddy waters kill algae or promote growth uncontrollably

human activities endanger 27% of reefs

oil spills, sewage, pesticides, silt run off destruct reefs

overfishing can disturb ecosystem balance

Plants and Animals of Oceans

Phytoplankton grow where there’s light for photosynthesis

Zooplankton that feed on phytoplankton, include jellyfish, tiny shrimp, fish larvae

Decomposers, filter feeders and organisms that feed on dead matter live in the bottom

8. How are animals of oceans threatened?

pollution from land activities ( run off from agriculture creates algal blooms), industrial wastes, sewage discharge

overfishing and fishing methods are destroying fish populations

Arctic & Antarctic Ecosystems

located at north and south poles

Depend on marine life for food

Supports plankton and huge diversity of fish

Arctic rich in nutrients from surrounding landmasses

Antarctic has never been colonized by humans