1. FRESHWATER BIOMES
Ecology
Chapter 10

2. Aquatic Biomes Water covers more than 70% of the Earth’s surface
Aquatic habitat: one in which organisms live in or on water
not grouped geographically
difficult to show on a map
often determined by depth rather than location

3. Land vs. Aquatic Biome
Temperature and rainfall are important factors when distinguishing one land biome from another.
Temperature in large bodies of water are relatively stable.
Rainfall has less effect on aquatic biomes because organisms are already underwater.

4. Important Factors
Salinity: The amount of dissolved salts in a sample of water. Measured in parts per thousand (# units of salt in a thousand units of water)
Aquatic biomes can be divided into two main groups
Saltwater (30 parts/1000)
Freshwater (0.5 parts/1000)
Brackish water > saline than fresh, < saline than ocean water

5. Important Factors
Depth – directly related to the amount of sunlight that reaches the bottom of the body of water.
Sunlight determines the types and amounts of plants that can grow. (Remember – plants are producers, and the base of the food web)

6. Photic zone: top layer of sunlight that receives enough sunlight for photosynthesis to occur.
Aphotic zone: below the photic zone. Sunlight does not reach this zone.
Benthic zone: the floor of a body of water

7. Question Break
What characteristic distinguishes the photic zone from the aphotic zone?
Sunlight
How is salinity measured?
Parts per thousand (# units salt/1000 units of water)

8. Standing-water Ecosystems
The most common types of standing-water ecosystems are lakes and ponds.
Also includes wetlands (bogs, swamps, etc.)
While there is no flow of water in and out of most standing-water ecosystems, there is a circulation of water throughout the system.
Review question: How does this circulation occur? What causes the circulation?

9. Types of Standing-Water Ecosystems
Abiotic Factors
Biotic Factors
Deepest type of standing water;
may have an aphotic zone; may be
fed by aquifers
Floating algae in the photic zone,
plants along shoreline, complex
food webs
Light reaches benthic zone; fed by
rainfall – may be seasonal
Main producers – plants and algae
that grow on bottom; food web
simpler than lakes
Plants have roots under water,
leaves above water; grasses,
cattails; ducks and waterfowl
Very shallow water, land occasion-
ally exposed; saturated soil; Florida
Everglades largest freshwater marsh
Land soaked due to poor drainage;
usually along low streambeds and
flat land
Large trees and shrubs; cypress
trees in south, willow and dogwood
in north
Inland wetland; soil is acidic; decay
is slow
Sphagnum moss dominant organ-
ism, partly decayed moss accumu-
lates as peat
Lake
Pond
Marsh
Swamp
Bog
Types of Standing-Water Ecosystems

10. Standing-Water Organisms
Several levels of habitat
Plankton community
Plankton: microorganisms that float on the surface of the water
Phytoplankton: carry out photosynthesis. Main producers in most aquatic biomes
Zooplankton: do not carry out photosynthesis. Include microscopic animals and protozoans. Consumers – feed on phytoplankton
Big fish feed on little fish, little fish feed on
plankton
Benthic community
Scavengers, depend upon a steady rain of organic material that drifts down from the top. Decomposers are also part of this community

11. Wetlands
Ecosystems in which the roots of plants are submerged under water at least part of the year. Soils are soaked with water, and very low in dissolved oxygen.
Marshes, swamps, bogs
Act as filters, detoxifying chemicals that passes through them
Can be used as part of a treatment system for waste water
Important breeding, feeding, and resting grounds for waterfowl.

12. Endangered Wetlands Wetlands are being destroyed by human activity.
Many do not find wetlands as attractive as other natural habitats
Land (especially in coastal areas) is developed for resorts and homes
Swamp Lands Act of 1849 encouraged the filling and draining of wetlands

13. Florida Everglades
Once a swampy marsh that covered 160 km from Lake Okeechobee to the tip of Florida.
Region has a wet season from May to October, followed by a dry season. Natural fires occur during the dry season, burning off dried plant material.
Home to a large number of organisms, that are adapted to the annual cycle of growth, drought, and fire.

14. In 1983, “Save Our Everglades” campaign was launched.
100,000 acres returned to wetland
Flow of water adjusted to provide a more natural water supply

15. Flowing-Water Ecosystems
Rivers, streams, creeks, brooks
All water that flows over land - to a scientist they are all streams
Water that flows underground is an aquifer
Stream Organisms
Adapted to the rate of the water’s movement
Hooks to grab hold of plants
Suckers that anchor to rocks

16. Stream Stages Youthful Old ________: _______: Rapids Waterfalls
Fast-moving water
Steep slope
_______:
Broad floodplain
Meanders
Oxbow lakes
Meander Scars

17. Important Definitions
River System
____________ – a stream and all its tributaries
________ – a smaller stream that empties into a larger stream
_________ – the land area drained by a river system
______ – a high point that separates river systems
Tributary
Watershed
Divide

19. ________ – the bends and curves of a stream
Meanders
________ – the bends and curves of a stream

21. Oxbow lake
deposition
erosion

24. ____________ – deposit formed when a stream spreads out onto a less steep area
Alluvial Fan

25. _____ – where a stream empties into a larger body of water
Delta
_____ – where a stream empties into a larger body of water

26. Ganges
River
Delta

27. Nile River Delta

29. Human Impact on Streams
Flow and course of streams has been changed by human activities
Dams create reservoirs and are used for hydroelectric plants
Dams and levees can be used to irrigate farmland
Dams and levees affect farmland by preventing sediments from being deposited on floodplains
Change of course damages or destroys the habitats of organisms
Areas that were once streambeds become the bottoms of deep lakes

30. Chapter 10 Review
To be considered fresh water, water must contain salt in a concentration
More than 30 parts per thousand
Less than 0.5 parts per million
More than 40 parts per million
Less than 0.5 parts per thousand

31. Brackish water is common in
Lakes
Oceans
Coastal marshes
aquifers

32. Sunlight reaches the benthic zone in
Ponds
Deep lakes
Oceans
Vents in the ocean floor

33. Organisms that live in the benthic zone of deep lakes are often
Producers
Plants
Scavengers
plankton

34. A type of standing-water habitat in which the soil is acidic and decay is slow is called a
Bog
Swamp
Marsh
pond

35. Phytoplankton are
Consumers
Decomposers
Producers
scavengers

36. Wetlands are Easy to define Have traditionally been protected by laws
Are nonproductive areas that could be better used for other purposes
Are important breeding grounds

37. Sediments tend to accumulate
In slow-moving parts of a stream
On the outer edge of a curve in a stream
In fast-moving parts of a stream
Near the beginning of the stream

38. Streams always flow South Toward the ocean Downhill
Toward the poles of Earth

39. Levees and dams are beneficial to farmlands because they
Prevent stream sediments from being deposited on the fields
Protect the fields from floods
Provide a source of irrigation
Help refill aquifers

40. Levees and dams are harmful to farm lands because they
Prevent stream sediments from being deposited on the fields
Protect the fields from floods
Provide a source of irrigation
Help refill aquifers