Transcript ch 6 ppt - Walton High School

Aquatic Biodiversity
Chapter 6
Chapter Overview Questions
What are the basic types of aquatic life
zones and what factors influence the
kinds of life they contain?
What are the major types of saltwater
life zones, and how do human activities
affect them?
What are the major types of freshwater
life zones, and how do human activities
affect them?
Aquatic Life Zones (Aquatic Biomes)
Characterized by amount of NaCl
dissolved in the water.
• Saltwater (marine) and freshwater
cover ~ 71% of the earth’s surface.
• Food chains and webs are more
complex and longer than terrestrial
ones.
•
AQUATIC ENVIRONMENTS
Figure 6-3
Organisms & Aquatic Life Zones
1. Plankton: free floating
- Phytoplankton: ex: algae
- Zooplankton: animal plankton.
ex: protozoans (amoeba, paramecia)
-Ultraplankton: autotrophic bacteria
2. Nekton: free-swimming. ex: fish, turtles, whales
3. Benthos: bottom dwellers. Ex: barnacles, lobsters
4. Decomposers: ex: bacteria, water molds
Limiting Factors
Life (numbers and diversity) in the surface, middle,
and bottom layers are determined by:
Temperature
Sunlight penetration (for photosynthesis):upper
layers or Euphotic zone
Amount of dissolved oxygen:  at lower levels
Nutrient availability (CO2, NO3-, PO43-):
shallow waters lots of nutrients
ocean-  nutrients, areas with upwelling have
 nutrients.
Marine Ecosystems
Scientists estimate
that marine
systems provide
$21 trillion in goods
and services per
year – 70% more
than terrestrial
ecosystems.
Figure 6-4
Oceans
• Largest of all ecosystems
• High biodiversity
• 2 zones:
1. Coastal- warm and nutrient rich area
90% of all marine species!  NPP
2. Open sea- cooler and less species
The Coastal Zone
Figure 6-5
Estuaries
• Enclosed body of water formed where
seawater mixes with freshwater from rivers &
streams.
• Called “ Marine nurseries”- habitats for many
juvenile fish species.
• Temperature and salinity vary due to the daily
tides and seasonal flow of freshwater
• Estuaries and coastal wetlands include inlets,
mangrove forest swamps, & salt marshes
Estuaries Con’t
• Extremely fertile due to constant movement
of water.
• Stressful conditions and abundant nutrients
result in low species diversity, but great
abundance of the species present.
• Helpful in filtering pollutants and sediments.
• Humans are constantly destroying and
degrading these ecosytems.
Estuaries and Coastal Wetlands:
Centers of Productivity
Estuaries and coastal marshes provide ecological
and economic services.
Filter toxic pollutants, excess plant nutrients,
sediments, and other pollutants.
Reduce storm damage by absorbing waves and
storing excess water produced by storms and
tsunamis.
Provide food, habitats and nursery sites for
many aquatic species.
Herring gulls
Peregrine falcon
Snowy
Egret
Cordgrass
Short-billed
Dowitcher
Marsh
Periwinkle
Phytoplankton
Smelt
Soft-shelled
clam
Zooplankton and
small crustaceans
Clamworm
Bacteria
Producer to
primary
consumer
Primary to
secondary
consumer
Secondary to
higher-level
consumer
All consumers
and producers
to decomposers
Fig. 6-7a, p. 131
Mangrove Forests
Are found
along about
70% of gently
sloping sandy
and silty
coastlines in
tropical and
subtropical
regions.
Figure 6-8
Intertidal Zone
• Where the ocean meets the land.
• Sometimes submerged and other times
exposed.
• Communities are constantly changing in this
area.
• Rocky shores- areas pounded by waves,
varieties of algae, snails, crabs, etc.
• Sandy shores- no plants or algae, but insects,
shorebirds, crabs, and worms found
Barrier Islands
• Long, narrow, offshore deposits of sand or
sediments that parallel the coast line.
• Aid in protecting mainland, estuaries, &
coastal wetlands.
• Found along eastern coasts and Gulf of
Mexico
• Lots of development
Ocean
Beach
Intensive
recreation,
no building
Primary
Dune
Trough
Secondary
Dune
No direct
No direct
Limited
passage
passage
recreation
or building and walkways or building
Back Dune
Most suitable
for development
Bay or
Lagoon
Intensive
recreation
Grasses
or shrubs
Bay shore
No filling
Taller shrubs
Taller shrubs and trees
Fig. 6-10, p. 133
Damage to barrier islands
A single home is left
standing among debris
from Hurricane Ike
September 14, 2008 in
Gilchrist, Texas.
Floodwaters from
Hurricane Ike were
reportedly as high as eight
feet in some areas causing
widespread damage across
the coast of Texas. (David
J. Phillip-Pool/Getty
Images)
Damage from
Hurricane Ike
Coral Reefs
• Structure that is formed by coral polyps
(small invertebrates that live in colonies).
• Typically found in warm coastal waters of the
tropics and subtropics.
• Coral polyps form a hard, stony, branching
structure made of limestone.
• New polyps attach to old coral and gradually
build the reef.
Coral Reefs Climate
• Usually found near land in shallow,
warm salt water.
• Lots of light
• Tropical temperatures, averaging 70°85° F
Importance of Coral Reefs
• High biodiversity- considered the most
diverse and productive
• Grow very slowly
• Complex relationships that exist between
many organisms.
• What are Coral Reefs?
Example of Food Chain
Damage to Coral Reefs
• Very sensitive to environmental changes.
• Natural disturbances: hurricanes or typhoons,
and predation by a large starfish-Acanthaster
• Anthropogenic disturbances (human)sediment run off, pollution, reef fishing,
bleaching…
• 300+ reefs are protected as reserves or
parks.
Effects of Human Activities on
Marine Systems: Red Alert
Human activities
are destroying or
degrading many
ecological and
economic
services provided
by the world’s
coastal areas.
Figure 6-13
Freshwater Life Zones
• Cover less than 1% of earth’s surface.
• Low salt concentration- < 1%
• Types:
Flowing (lotic) - streams, and rivers
Standing (lentic) - ponds, lakes, inland
wetlands
Natural Capital
Freshwater Systems
Ecological
Services
Economic
Services
Climate moderation
Food
Nutrient cycling
Drinking water
Waste treatment
Irrigation water
Flood control
Hydroelectricity
Groundwater
recharge
Transportation
corridors
Habitats for many
species
Recreation
Genetic resources
and biodiversity
Employment
Scientific
information
Fig. 6-14, p. 136
Lakes and Ponds Zones
• divided into four different “zones” determined by
depth and distance from the shoreline:
1. Littoral zone- top layer, shallow/near shore, 
biodiversity. aquatic plants, grazing snails, clams, insects,
crustaceans, fishes, and amphibians
2. Limnetic zone-sunlit water surface layer, main
photosynthetic layer. plankton, fishes
3. Profundal zone-cool and dark layer,  O2
4. Benthic zone-bottom layer, decomposers and
detritivores.
Lakes: Water-Filled
Depressions
During summer and winter in deep temperate zone
lakes the become stratified into temperature layers
and will overturn.
This equalizes the temperature at all depths.
Oxygen is brought from the surface to the lake
bottom and nutrients from the bottom are brought
to the top.
What causes this overturning?
Freshwater Life Zones
Standing water
Flowing water
Fig. 7-16 p. 139
Lake Classification
Classified by: nutrient content and primary
productivity
Oligotrophic
Newly formed
Poorly nourished
Little sediment
Deep water
Clear water color
Low net primary prod.
Trout, smallmouth bass
Eutrophic
Excess supply of nutrients
(Phosphates & nitrates)
Shallow water
Murky water color
High net prod.
Lots of plants, fish,
plankton
MESOTROPHIC LAKES- intermediate
between oligotrophic and eutrophic
Effects of Plant Nutrients on
Lakes:
Too Much of a Good Thing
Plant nutrients from a lake’s
environment affect the types and
numbers of organisms it can support.
Figure 6-16
Effects of Plant Nutrients on
Lakes:
Too Much of a Good Thing
Cultural eutrophication:
Human inputs of nutrients from the
atmosphere and urban and agricultural
areas can accelerate the eutrophication
process.
Eutrophication Super Simple
Terminology
Surface water- precipitation that does not
sink into ground or evaporate
Runoff- surface water that flows into
streams
Watershed (Drainage basin)- The region
draining into a river, river system, or other
body of water.
What is a Watershed?
Characteristics of Rivers and Streams
• bodies of flowing water moving in one
direction
• found everywhere—they get their start at
headwaters, which may be springs, snowmelt
or even lakes
• travel all the way to their mouths, usually
another water channel or the ocean
Zones of Down Hill Water Flow
•
Characteristics of river/stream change as
water moves through these zones.
1. Source zone- narrow headwaters. water moves
rapidly, clear water,  D.O.
2. Transition zone- wider and deeper. Slower and
warmer water, Lower D.O. than source zone
3. Floodplain zone- stream join into rivers. Warmer
water and lower D.O., muddy water
Freshwater Streams and Rivers:
From the Mountains to the Oceans
Water flowing from mountains to the sea
creates different aquatic conditions and
habitats.
Figure 6-17
Freshwater Inland Wetlands:
Vital Sponges
Inland wetlands
act like natural
sponges that
absorb and store
excess water
from storms and
provide a variety
of wildlife
habitats.
Figure 6-18
Freshwater Inland Wetlands
• Lands that are covered with fresh water year round
•
•
•
•
or seasonally and located away from coastal areas.
High biodiversity
Ex: Marshes, Swamps, Floodplains, and Artic tundra
(summers)
Vary in size- small to large
Important in filtering pollutants, absorbing excess
water from storms, & providing habitats
Impacts of Human Activities on
Freshwater Systems
Dams, cities, farmlands, and filled-in wetlands alter
and degrade freshwater habitats.
Dams, diversions and canals have fragmented about 40%
of the world’s 237 large rivers.
Flood control levees and dikes alter and destroy aquatic
habitats.
Cities and farmlands add pollutants and excess plant
nutrients to streams and rivers.
Many inland wetlands have been drained or filled for
agriculture or (sub)urban development.