Bellringer
• Describe the different plants and animals in the
salt water aquarium show in the picture.
• What requirements do the fish in the aquarium
need to survive?
• What would happen if a fish from a local
Alabama river was added to this salt water
aquarium? WHY?
Aquatic Ecosystems
Chapter 7
Objectives:
1. Describe features of freshwater
and marine ecosystems.
2. Describe threats to freshwater
and marine ecosystems.
Aquatic Ecosystems
• How many aquatic ecosystems can you
name?
• What are the differences between them?
I. Freshwater Ecosystems
• Organisms are grouped by location and
adaptations:
– Plankton – float near the surface of the
water
• Phytoplankton – microscopic plants
• Zooplankton – microscopic animals
– Nekton – free-swimming (fish, turtles,
whales)
– Benthos – bottom-dwellers (mussels, worms,
barnacles)
A. Lakes and Ponds
• Littoral zone
– nutrient-rich area near shore
– variety of plant and animal life
• Benthic zone
– Bottom of a pond or lake
– Inhabited by decomposers, insect larvae, and clams
• Eutrophication –
– more nutrients = more plants = more decomposers
using oxygen = less oxygen for other organisms
– Can be caused by runoff of sewage, fertilizers,
animal waste
B. Wetlands
• Marshes (Ex: The Everglades)
– Contain non-woody plants (reeds, rushes,
cattails)
• Swamps (Ex: Louisiana swamps)
– Contain woody plants or water-loving trees
Functions of Wetlands
• Trap sediments, nutrients, and
pollutants, keeping them from lakes,
reservoirs, and oceans
• Buffer shorelines against erosion
• Protect against flooding
• Provide spawning grounds and habitats
• Recreational areas (fishing, birdwatching, hiking, canoeing, photography)
Human Impact on Wetlands
• Were drained and filled for farming and
residential and commercial development
• Pollution
C. Rivers
• Swift-moving
• Home to strong swimming fish and
organisms with adaptations to cling to
rocks
• Polluted by
– human sewage and garbage
– runoff from the land
• Drained by industries
#41 - Concept Map
1. Freshwater wetlands 2. Decomposers
3. Lakes
4. Phytoplankton
5. Littoral zone
6. Zooplankton
7. Freshwater ecosystems 8. Runoff
9. Eutrophication
10. Traps and filters pollutants
11. Benthic zone
12. Buffers shorelines
II. Marine Ecosystems
• Mainly in coastal areas and the open
ocean
A. Coastal Wetlands
•
Coastal areas covered by salt water at least
part of the time
1. Estuaries – where fresh river water and
salty ocean water mix
•
•
•
•
Constant source of fresh nutrients supplied by
the river
Nutrients fall to the bottom (“nutrient trap”)
Provide harbors protected from open ocean –
site of major ports
May be used as dumping sites for sewage,
industrial waste, and agricultural runoff
Coastal Wetlands (cont.)
2. Salt marshes
– Develop in estuaries
– Found along the Gulf Coast
Coastal Wetlands (cont.)
3. Mangrove swamps
– Found along the coast in tropical and
subtropical zones
– Dominated by mangrove trees
Coastal Wetlands (cont.)
4. Rocky and sandy shores
–
–
Rocky shores have more plants and
animals (Why?)
Barrier islands run parallel to the shore
and protect the mainland and coastal
wetlands.
Barrier
Islands
B. Coral Reefs
• Limestone ridges made of the skeletons of
animals called coral polyps
• Found in shallow, tropical seas with clear,
warm salt water and lots of light
• Disappearing coral reefs:
– Damaged by oil spills, sewage, and runoff
– Overfishing
– Damaged by anchors, divers, shipwrecks
C. Oceans
• Plankton on the ______; decomposers
and filter feeders on the ________.
• Threats to the ocean:
– Pollution from land activities
– Overfishing
• Arctic and Antarctic ecosystems:
– Nearly all food in the arctic ecosystem comes
from the ocean; land is frozen, so plants
don’t grow well.
Assignment 
•
Compare and contrast
1. Salt marshes (p.182) and freshwater
marshes (p.176)
2. Mangrove swamps (p.182) and freshwater
swamps (p.177)