Transcript Biomes - Choteau

Chapter 3
Communities and Biomes
Section 2, Part 1
Aquatic Biomes
Biomes
A large group of ecosystems that
share the same type of climax
community.
Aquatic Biomes
• Approx. 75% of Earth is covered by water.
• 3 Main Aquatic Biomes
– Marine Biomes
– Estuaries – Mixed Waters
– Freshwater Biomes
Marine Biomes – Open Oceans
• Differ in abiotic factors, such as:
– Salinity, depth, light, and temperature
• Large amounts of biomass.
– Mostly extremely small to microscopic organisms,
which larger organisms depend on.
– Plankton
• Small organisms that drift and float.
• Include autotrophs, diatoms, eggs, and juvenile stages
of marine animals.
• Serve as the base of all aquatic food chains.
Zones
• Photic Zone
– Shallow enough for sunlight to penetrate.
– Exist along coastlines.
– Include bays, rocky shores, sandy beaches,
mud flats, estuaries, and coral reefs.
Zones
• Aphotic Zone
– Deeper water that never receives sunlight.
Estuaries
• Coastal body of water, partially
surrounded by land, in which freshwater
and saltwater mix.
• Salinity changes with the tides and the
amount of freshwater brought in by rivers.
• Because of salinity changes, a wide range
of organisms can live in estuaries.
Salt Marsh Ecosystems
• Dominated by salt-tolerant smooth
cordgrass, salt marsh hay, or eelgrasses.
– Grasses grow so thick that their stems and
roots form a tangled mat that traps food and
provides a “nursery” habitat for small
developing snails, crabs, and shrimp.
• These organisms feed on suspended decaying
material.
• Attract predators, such as birds.
Intertidal Zones
• The portion of the shoreline that lies
between the high and low tide lines.
• Size of the zone depends upon the slope
of the land and the difference between
high and low tides.
• Intertidal ecosystems have high levels of
sunlight, nutrients, and oxygen.
Intertidal Zones
• Differs in rockiness and wave action.
– Rocky
• Waves constantly threaten to wash organisms into
deeper waters.
– Organisms such as snails and sea stars have adaptations
that act by suction to hold onto rocks.
– Barnacles secrete a strong glue which helps them stay
anchored.
– Sandy
– Clams, worms, snails, and crabs survive by burrowing in
the sand.
Tide Pools
• Pools of water left when the water is a t
low tide.
– Can isolate organisms that live in the intertidal
zone until the next high tide.
– Can vary in nutrient and oxygen levels from
one time of day to another.
Marine Biomes
• As you move into deeper water, the ocean
bottom is less affected by waves and
tides.
• Nutrients washed from land by rainfall and
runoff contribute to the abundant life and
high productivity.
Coral Reefs
• One of the most diverse ecosystems.
• Formed over long periods of time from the
calcium carbonate shells secreted by
corals.
• Very fragile ecosystem.
Freshwater Biomes
• Rivers and Streams
– Quicker flowing streams and rivers have
higher oxygen content.
– Higher nutrients and plant life exist in slower
moving parts.
Lakes and Ponds
– Organisms
• Cattails, tadpoles, aquatic insects, turtles, worms,
crayfish, insect larvae, whirligig beetles,
dragonflies, and fish.
– Temperature
• Decreases with depth.
– Sunlight
• Decreases with depth.
Wetlands
• Marshes and Swamps
– Found inland and in coastal regions.
– Highly productive and are the source of food for
many migratory birds.
– Have flowing water.
– Swamps have trees. Marshes do not.
• Bogs
– Get their water supply form rain.
– No flowing water.