Transcript Marine Ecosystems

Marine
Ecosystems
Composition of Water on Earth
1. Saltwater: 97.5% of Earth’s
water
2. Freshwater: 2.5% of Earth’s
water
a. Greatest amount is found in
polar ice caps and glaciers
b. 0.01% available for use
The Oceans
1. The ocean is divided into 5 oceans (Southern Ocean was
added in 2000)
2. Pacific ocean is the largest; more than ½ of Earth’s water &
covers ⅓ of Earth’s surface
3. Oceans have changed over time due to plate tectonics
Aquatic Life Zones
1.
2.
3.
4.
Aquatic Life Zone: biomes of water
Saltwater versus Freshwater
Distribution of organisms is determined by salinity (Salt
content) of water
Saltwater (marine) life zones include:
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5.
Oceans & bays
Estuaries
Coastal wetlands
Shorelines
Coral reefs
Mangrove forests
Freshwater life zones include:
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Lakes and ponds
Rivers and streams
Inland wetlands
Organisms in the Life Zones
1. Plankton: weakly swimming,
free-floating
 Phytoplankton: algae
 Zooplankton: 1° consumers; eat
plankton & 2° consumers
zooplankton
 Ultraplankton: very small
photosynthetic plankton
 70% of primary productivity of
ocean
2. Nekton: strong swimming
consumers such as fish,
turtles, & whales
3. Benthos: bottom dwellers
(sessile); such as oysters &
sea stars
4. Decomposers (bacteria) break
down dead organic matter & waste
into nutrients
Abiotic Factors that Determine types and
Numbers of Organisms
1. Salinity (salt concentration)
2. Light penetrates to depth of 30 m (100 ft)
below water surface
3. Currents / waves: present or absent
4. Level of essential nutrients: upwelling
brings nitrates (NO3–) and phosphates
(PO43–) from ocean bottom to surface
Abiotic Factors that Determine
types and Numbers of Organisms
5. Dissolved oxygen (DO);
varies according to
temperature and number
of consumers
6. pH
7. Temperature;
decreases with water
depth
Marine Life Zones
1. 3 factors that divide the ocean into marine life zones
 sunlight
 distance from shore
 water depth
Turbidity: degree to which
the water loses its
transparency due to the
presence of suspended
particulates. The more
turbid, the less sunlight can
penetrate through and the
less photosynthesis
Coastal Zone
1. Characteristics:
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Warm, nutrient rich shallow
water
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Extends from high tide mark
on land to edge of continental
shelf
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Less than 10% of ocean area
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Contains 90% of all marine
species
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Site of most large commercial
fisheries
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High net primary productivity
from photosynthesis
2. Examples
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Estuaries
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Coastal marshes
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Mangrove forests
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Coral reefs
Estuaries: Where River Meets the Sea
Estuaries provide buffers against coastal storm impacts and
nursery areas for many commercial and recreational fish.
Ecosystem Services of Aquatic
Environments
1. Ecosystem services:
the benefits that
humans get from the
ecosystems where they
live and around the
world.
2. These are typically not
benefits that people pay
for directly; often we are
unaware that we are
getting anything at all.
Mangrove Forests
1. Mangroves: trees & shrubs that grow in intertidal zones of
estuaries, coastlines, and islands.
2. Form a forest in the tidal zone between land and sea.
3. Found in tropical and subtropical areas
4. Thrive in areas of high salinity
 Mangrove trees have aerial roots that filter salt out of saltwater
5. Rich in biodiversity! home to countless species of animals,
including fish, shrimp, crabs, mollusks, manatees, sea turtles,
fishing cats, monitor lizards and mud-skipper fish.
1. “Rainforest of the Sea”
2. Less than 0.1% of ocean
surface, but contain 25%
of all marine species
3. Zooxanthella are singlecelled algae that live in
the tissues of animals
such as corals
 Mutualistic
relationship between
algae (algae give food
& O2 for coral & coral
provide protected
environment & CO2 for
photosynthesis)
 represents a highly
efficient exchange of
nutrients in a nutrientpoor environment.
Coral Reefs
Ecosystem Services of Coral Reefs
Intertidal Zone
1. Adaptations of organisms living in Intertidal Zone:
 Organisms must be able to avoid being swept away (many are sessile) or
crushed by waves (hard exoskeleton)
 Must be able to survive being immersed in water in high tide and exposed to
air in low tide
 Must be able to survive changing salinity levels
Open Sea
1. Great increase in water
depth
2. Divided into 3 vertical zones
based on the penetration of
sunlight
3. Temperature decreases
with water depth
1. Characteristics of Euphotic Zone:
 Brightly lit upper zone
 Drifting phytoplankton carry out 40%
of world’s photosynthetic activity
 Low nutrient levels
 High levels of dissolved oxygen
 Organisms: large, fast swimming
fish such as swordfish, sharks, &
bluefin tuna
2. Upwelling: ocean currents driven
by differences in temperatures or
by coastal winds bring water up
from abyssal zone
 Brings nutrients from ocean bottom
to the upper levels
 Producers use nutrients
Euphotic
Zone
1. Characteristics of Bathyal
Zone
 Middle zone
 Receives little sunlight
 Zooplankton and smaller
fishes (may migrate to upper
surface to feed)
 Also contains squid, large
whales, and octopi
 The fish in this zone have
become very energy
efficient, since it is especially
hard to find nutrients.
 Many organisms have slow
metabolic rates to conserve
energy.
Bathyal Zone
Abyssal Zone
1. Characteristics of the Abyssal Zone:
 Dark and very cold
 No photosynthesis
 Little dissolved oxygen
2. “Marine snow”: dead and decaying organisms that drift
down from upper levels
Freshwater
Ecosystems
Standing Water Life Zones
1. Also called lentic (Latin : lentus which means sluggish)
2. Form when precipitation, runoff, streams, rivers, &
groundwater seepage fill depressions in Earth’s surface
3. Vary in size, depth, & nutrient content
Zones of a Lake
Littoral Zone
1. Top zone near the shore
2. Consists of shallow, sunlit
waters to depth at which
rooted plants stop growing
3. High biodiversity because of
ample sunlight & nutrient
input from surrounding land
4. Organisms consists of:
rooted plants, turtles, frogs,
crayfish, bass, perch, and
carp
Limnetic Zone
1. Open, sunlit surface layer
away from the shore
2. Extends to depth
penetrated by sunlight
3. Main photosynthetic zone;
produces food and O2 that
support the consumers
4. Most abundant organisms
are phytoplankton &
zooplankton
5. Large species of fish live
here
Profundal Zone
1. Layer of deep, open water where it is too dark for
photosynthesis
2. Cell Respiration occurs in all layers; this is a layer of
oxygen consumption; O2 levels low
3. Fish are adapted to cooler, darker water
Benthic Zone
1. Bottom layer
2. Decomposers, detritus feeders & some benthos fish live
here
3. Nutrients come from dead organic matter from littoral &
limnetic zones & sediments washed into lake
Oligotrophic Lakes
1. "Oligo" means very little; have very
little nutrients (N & P)
2. Deep and has steep banks
3. Glaciers & mountain streams
supply water
4. Not much sediment brought into
lake
5. Clear water; not much algae
6. Rocky or sandy bottom
7. Fish include small mouth bass and
trout
8. Little photosynthesis so low
primary productivity
Eutrophic Lake
1. Truly nutrient rich (N & P)
2. Shallow and have murky water and
mucky, soft bottoms.
3. Also have a lot of plants and algae
4. Nutrients support high densities of
algae, fish and other aquatic
organisms
5. With all of the biomass, there is a lot
of decomposition occurring at the
bottom which uses up O2
6. decomposition uses up O2 causing
the bottom of the lake to become
anoxic (depleted of O2 ) causing
fish kills
Mesotrophic Lake
1. Meso means middle; medium
amount of nutrients (N & P)
2. Algae carry out photosynthesis;
supply O2 for fish
3. Fish include sport fish such as
walleye, perch, and smallmouth
bass
Lake Turnover
Water is densest
at 4° C
Winter: coldest
H2O lies just
below surface ice;
water
progressively
warmer at deeper
levels, resulting in
thermal
stratification
Spring:
Ice melts, &
surface water
warms to 4°C &
sinks, eliminating
temperature
differences.
Winds mix water,
brings O2 to
bottom &
nutrients to top.
Summer:
Lake regains
thermal
stratification, with
warm surface
H2O separated
from cold bottom
water by narrow
zone of rapid
temp change
(thermocline)
Autumn:
Surface water
cools & sinks
below underlying
layers, remixes
the water until the
surface begins to
freeze & winter
temperature
profile is reestablished
Zones of a Stream
Source Zone
1. Headwaters or highland streams
2. Shallow, cold, clear, & swiftly
flowing
3. Water tumbles downward over
rocks, waterfalls, rapids & picks up
O2 from air
4. Not much photosynthesis; low
primary productivity
5. Nutrients come from organic matter
(leaves, branches, & bodies of
living and dead insects)
6. Fish: cold water such as trout that
need a lot of dissolved O2
Transition Zone
1. Streams merge and form wider,
deeper, and warmer streams
2. Flow down gentler slopes with
fewer obstacles
3. Can be more turbid from
sediment, slower flowing, and
have less DO than headwaters
Floodplain Zone
1. Streams join into wider and
deeper rivers that flow across
broad, flat valleys.
2. Water is warmer and has less DO
than source and transitional zones
3. Water tends to be very turbid with
suspended sediment
4. San Jacinto River in the Humble /
Atascocita area is in the floodplain
zone
Riparian Zone
1. Areas that surround water bodies in the watershed, composed of
moist to saturated soils, water-loving plant species & their
associated ecosystems.
2. Transition areas that connect the water with the land
3. Complex interactions among the water, soil, microorganisms,
plants and animals
4. Corridors for wildlife to travel between ecosystems
Ecosystem Services of Riparian Zones
1. Healthy riparian zones filter and purify water for drinking,
irrigation and recreation
2. Vegetation and soils in riparian zones soak up and store
water during high rainfall events
3. Stream corridor vegetation gives stability to stream
banks and prevent erosion
4. Help to regulate greenhouse gases by producing large
volumes of trees that remove CO2 from atmosphere
5. Complex interrelationships between microorganisms,
plants and nutrients in riparian areas help to break down
contaminants that we discharge into the environment