Chapter 10 and 11 (pgs 154 – 181)
Environmental Science
CHAPTER 10: FRESHWATER BIOMES
10.1 AQUATIC BIOMES
 Water covers 70% of Earth’s surface.
 Aquatic habitat: habitat in which organisms live on or
in water.
 Most important factors:
 1. Amount of dissolved salts.
 2. Depth
Salinity
 Salinity: amount of dissolved salts in a sample of water.
 Allows us to divide water into 2 groups:
 1. Saltwater-30 parts per thousand.
 2. Freshwater-0.5 parts per thousand.
 Brackish water-in the middle. Common where
freshwater meets the ocean.
Saltwater
Freshwater
Brackish water
Hypersaline Lakes
Depth
 Directly related to amount of sunlight that reaches the
bottom of body of water.
 Sunlight determines the plants that grow on the
bottom.
 Bodies of water can be divided into depth zones:
 Photic Zone
 Aphotic Zone
 Benthic Zone
Depth Zones Diagram
 Photic Zone: top layer of water that receives enough
sunlight for photosynthesis to occur.
 About 100 meters in open ocean.
 Aphotic Zone: below the photic zone. Sunlight never
reaches here. Only found in oceans and very deep
lakes.
 Benthic Zone: floor of a body of water.
CHECK FOR UNDERSTANDING:
What characteristic distinguishes the photic zone
from the aphotic zone?
2. How is salinity determined and measured?
3. Suppose a friend wants to set up an aquarium and
discovers that saltwater fish are more attractive, but
a freshwater aquarium is easier to maintain. Your
friend decides to set up a freshwater aquarium, but
buys some saltwater fish to place in it. Predict what
the result of this decision would be and why.
1.
10.2 STANDING-WATER ECOSYSTEMS
 Freshwater biomes:
 1. Standing-water ecosystems

Lakes and ponds, wetlands, bogs, swamps, marshes
 2. Flowing-water ecosystems
Lake
 Deepest standing
water; may have
aphotic zone; may be
fed by underground
aquifers.
 Main producers:
floating algae and
benthic plants along
shoreline.
Pond
 Light reaches benthic
zone; fed by rainfall;
may be seasonal.
 Main producers: plants
and algae that grow on
bottom.
Marsh
 Very shallow with land occasionally exposed; soil saturated;
very low oxygen in water; salinity may vary (Florida
Everglades)
 Plants: roots under water, leaves above water; grasses,
cattails, rushes; ducks, waterfowl, benthic animals
common.
Swamp
 Poor drainage (land soaked with water); along low
streambeds and flat land.
 Large trees and shrubs; plants grow in muddy, oxygenpoor soil; cypress trees, willow, dogwood.
Bog
 Inland wetland with little
inflow or outflow; soil
acidic; decay slow.
 Sphagnum moss
dominant; decayed moss
accumulates.
Standing-Water Organisms
 Upper level of water.
 Plankton: microorganisms that float on the surface of
the water.


1. Phytoplankton: plankton that carry out photosynthesis.
(producers)
2. Zooplankton: plankton that do not carry out
photosynthesis. (consumers)
 Benthic level
 Scavengers
 Food chain: phytoplanktonzooplanktonsmall fish
large fish
Wetlands
 Wetlands: ecosystems in which the roots of plants are
submerged under water at least part of the year.
 Examples: marshes, swamps, bogs.
 Soil soaked with water; low in oxygen.
 Water may be fresh, brackish, salt water, or flowing.
 Detoxify chemicals in the water that passes through
them.
 Breeding, feeding, resting grounds for waterfowl.
 Flood protection
 Refill aquifers
 Human Activity
 Destroy because we don’t like the animals there.
 It is not attractive to us.
 Like waterfront view.
The Florida Everglades
 Used to span 160 km from Lake Okeechobee to tip of
Florida.
 Maximum water depth 2 meters.
 Wet season from May-October.
 Much drained to create farmland.
Map of Florida Everglades…
CHECK FOR UNDERSTANDING:
Where would you be likely to find benthic organisms
in an aquatic ecosystem?
2. What is the difference between the role of
phytoplankton and the role of zooplankton in an
aquatic food web?
1.
10.3 FLOWING-WATER ECOSYSTEMS
Stream Organisms
 Adapted to living in flowing-water.
 Insects have hooks to grab hold of plants.
 Fish “smell” chemicals in the water to return to old
breeding grounds.
Stream Flow
 Flow to ocean because of gravity.
 Source (head) of stream: where stream begins.
 Headwater- water near the stream source.
 Sediments: small particles that settle to the bottom of
a body of water.
 Accumulate on bottom; provide place for plant roots to
grow.
 Slow flow of water.
 Cause stream to change course over time.
CHECK FOR UNDERSTANDING:
What condition encourages sediments to settle out of
the flowing water in a stream?
2. Why are there fewer organisms in the headwater of a
stream than further downstream?
1.
CHAPTER 11: THE MARINE BIOME
11.1 THE WORLD OCEAN
 The water between the continents.
 All oceans are connected.
 Zones based on depth:
 Photic zone
 Aphotic zone
 Benthic zone
 Zones based on distance from shore:
 Intertidal zone
 Neritic zone
 Oceanic zone
Zones of the ocean diagram:
The Oceanic Zone
 Oceanic Zone: open ocean; the largest zone, making up
more than 90% of the surface area of the world ocean.
 500 – 11,000 meters below ocean surface.
 Not much sunlight.
 Photic Zone
 Phytoplankton are main producers.
 Aphotic Zone
 Many organisms feed on what drifts down.
 Detritus: tiny pieces of dead organic material that are food for
organisms at the base of the aquatic food web.
Ocean Water
 Near equator
 Warmer, more saline, higher mineral content.
 Near poles
 Less salty, denser.
 Ocean currents: characteristic patterns the water flows
in.
 Driven by wind.
CHECK FOR UNDERSTANDING:
What is detritus made of, and why is it important to
deep sea organisms?
2. Why does the oceanic zone have no plants? What are
the producers of the open ocean?
1.
11.2 NERITIC ZONES
 Continental Shelf: shallow border that surrounds the
continents.
 Area between the shore and about 500 meters below the
surface of the water.
 Neritic Zone: region between the continental shelf and
the surface of the water.
 In the photic zone.
 Reefs and estuaries.
Coral Reefs
 Reef: natural structure built on a continental shelf.
 Made from products of reef organisms.
 In warm, tropical waters.
 Breeding and feeding grounds for many fish.
 Protect shoreline from erosion.
 VERY diverse.
 Reef made of:
 Calcium carbonate skeletons of corals.
 Symbiotic relationship between coral and alga inside
tissue of coral. Coral have polyp-shaped bodies and
stinging cells.
 Humans harm reefs:
 Blast with dynamite.
 Harvested and sold for jewelry.
 Fish used in aquariums.
 Water pollution
Picture of a coral
Estuaries
 Estuary: region of water in which a freshwater source,
usually the mouth of a river, meets salt water from the
ocean.
 Brackish water.
Picture of estuary
Neritic Zone Productivity
 Factors:
 Availability of sunlight allows photosynthesis.
 High in mineral nutrients.
 Tides
CHECK FOR UNDERSTANDING:
Where in the ocean does the neritic zone begin and
end?
2. Some types of ecosystems recover from damage more
quickly than others. Would you expect coral reefs to
recover quickly from the types of damage described in
this section? Why or why not?
1.
11.3 INTERTIDAL ZONES
 Intertidal zone: along the shoreline; alternates
between periods of exposure and periods of
submersion twice a day.
 Organisms must survive: submersion, exposure,
pounding by surf.
 Surrounded by wetlands.
Salt Marshes
 Flat, muddy wetlands that often surround estuaries,




bays and lagoons.
Influenced by tides.
Support migratory bird populations.
Support ocean ecosystem.
Form when streams flow into waters of estuaries or
other shallow, neritic waters.
 Slowing of waters cause sediments to be deposited in
mouth of stream. Sediments build up over time,
forming a delta.
 Subsidence: delta sinks under the water due to the
weight of the accumulated sediments.
Mangrove Swamps
 Coastal wetlands that occurs only in warm climates.
 Mangrove-woody plant that is either a tree or a shrub.
 Roots that emerge from water.
 Very little dissolved oxygen.
CHECK FOR UNDERSTANDING:
1.
Why are salt marshes considered part of the intertidal
zone?