Download Types of Aquatic Life

Aquatic info
Saltwater: AKA marine. 3.5% salt +35 ppm
concentration.
Brackish water is less salty than marine, but too salty to
be freshwater. Places where fresh and salt water meet.
Coastal estuaries, seas, few lakes
Freshwater: less than 1% salt concentration. <35 ppm
Rivers, lakes, ponds, streams.
How have fish adapted to fresh and salt water?
OSMOSIS REVIEW!!!!!
• Aquatic Life - saltwater
Plankton: drifting or weakly swimming life forms.
– Phytoplankton: plant plankton, floating…important?
– Zooplankton: animal plankton, weak swimming
• Ultraplankton: photosynthetic bacteria,
•
•
•
microscopic. May be responsible for 70% of
primary productivity at ocean surface.
Nekton: strong swimming consumers.
Fish, turtles, whales
Benthos/Benthic: bottom dwellers.
Oysters, tube worms, lobsters, Crabs.
Decomposers: mostly bacteria that break
down dead organic matter.
Where do they fit?
Key Characteristics of Aquatic
Ecosystems
1. Less pronounced and fixed boundaries
than terrestrial ecosystems.
2. Longer, more complex food chains
3. Difficult to study and monitor because
of size and they are hidden from view.
4. Life is found in distinct zones or layers –
surface, middle, bottom
Limiting Factors for Life Under
water
1. Temperature – gets colder the deeper
the water
2. 2. Light – gets darker the deeper the
water
3. 3. Dissolved oxygen content
4. 4. Dissolved nutrients such as
C, P, and N
5. 5. pH
These are the basic measurements of water quality
Oxygen
Oxygen
a. Enters the system through atmosphere
and photosynthesizing organisms
b. Is depleted by respiration (fish gills)
c. Can vary within an ecosystem due to
temperature, number of producers,
number of decomposers, and circulation of
water
What about respiration rates of fish, DO and
temp?
Why do some fish seek cooler water?
• DO in relation
to depth
• What do you
think happens
to the
diversity of
critters with
depth?
DO vs Depth of a lake
DO vs time of the year. Is this
true for the whole earth?
Oxygen and Carbon Dioxide
Carbon dioxide
a. Enter through atmosphere and respiring
organisms.
b. Can be depleted by photosynthesizing
organisms, organisms using carbonate
ions to make shells skeletons, and through
sedimentation (rock formation).
c. Carbon sink
Where is the water and life at?
In the Zone! Its deep!
• •Euphotic zone: top layer that sunlight can
penetrate. Pollution, algae, etc, can reduce
depth of this zone. Photosynthesis usually
confined to this layer. Higher D.O. levels.
• •Bathyal Zone: second layer down, “twilight”
Typically between 200-1500m. Less animal life
than euphotic zone. These animals come to the
euphotic zone to feed
• •Abyssal zone: Extremely deep, below 1500m
Few life forms; little D.O. Strange looking
creatures!
Horizontal Zones
• Estuarine zone: places where freshwater
meets sea water. Salt concentrations will vary.
• Coastal Zones: teeming with life. Area above
the continental shelf.
• Open sea: area beyond the reach of the
continental shelf.
• Intertidal zones: area between high and low
tides.
Sun
Euphotic Zone
Photosynthesis
Estuarine
Zone
Continental
shelf
Open
Sea
Sea level
Bathyal Zone
Abyssal
Zone
Darkness
High tide Coasta
l Zone
Low tide
Found Nemo!! YUM!!!!
Nemo’s House
• Coral Reef: typically in warm, coastal marine
regions. Filled with life and biodiversity!
• More than Nemo lives here – 25% of all marine species,
66% of all marine fish species live here.
• Protect about 15% of coastline from erosion by slowing
incoming waves
• In danger: we’ve lost 25% of coral reefs because of
coastal development, pollution, overfishing, ocean
warming
Coral Reef
• Can only form in warm, tropical, shallow oceans with
stabile high salinity.
• Required temps: 18 – 30o C (64-86oF)
• Bleaching can occur at 31o C!
• Affected by: temperature increases, sedimentation,
pollution, floods, storms, predatory fish.
• Good news: a growing number of coral reefs are now
•
listed as preserves or protected.
Artificial reefs…restoration
Coastal reefs
The Great Barrier Reef Aus.
Atoll reefs Found in the South
Pacific Sea
Bleaching of coral
Nuke Testing on reefs!
Sunken ships
Navy Scraps ships and sinks???
Used tires
Estuaries and Coastal Wetlands:
They’re Productive!
• Estuaries include river
mouths, inlets, bays,
sounds, salt marshes
in temperate zones
and mangrove forests
in tropical zones.
Mangrove Forests
• Are found along
about 70% of
gently sloping
sandy and silty
coastlines in
tropical and
subtropical
regions.
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.
Rocky and Sandy Shores:
Living with the Tides
• Organisms experiencing daily low and high
tides have evolved a number of ways to
survive under harsh and changing conditions.
– Gravitational pull by moon and sun causes tides.
– Intertidal Zone: area of shoreline between low
and high tides.
Rocky and Sandy Shores:
Living with the Tides
• Organisms in
intertidal zone
develop specialized
niches to deal with
daily changes in:
– Temperature
– Salinity
– Wave action
Barrier Islands
Low, narrow, sandy islands that form offshore
from a coastline.
• Primary and secondary dunes on gently
sloping sandy barrier beaches protect land
from erosion by the sea.
Ocean
Beach
Intensive
recreation,
no building
Primary
Dune
Secondary
Dune
Trough
No direct
No direct
Limited
passage
passage
recreation
or building and walkways or building
Grasses
or shrubs
Back Dune
Most suitable
for development
Bay or
Lagoon
Intensive
recreation
Bay shore
Taller shrubs
No filling
Taller shrubs and trees
Productivity and Aquatic
Ecosystems
The more light and nutrients available in
an ecosystem the more productive
Shallow waters with lots of nutrient = high
productivity.
Open ocean = low productivity
What about deep ocean?