Transcript Aquatic Ecosystems

Aquatic Ecosystems
Ch 7 & more
Note: slides 1-27 apply to the
Freshwater Unit
28-48 are for the Marine Unit
Aquatic Ecosystem
Food Webs
• plankton: tiny
organisms that drift
with the currents
• basis of all aquatic
ecosystems
– Phytoplankton
• Autotrophs
• Algae
– Zooplankton
• Tiny animals or protozoa
• Heterotrophs
• Eat phytoplankton
http://www.lhup.edu/smarvel/Seminar/FALL_2000/Picking/Picking.htm
Aquatic Ecosystem Food Webs
• Nekton = Freeswimming organisms
– Fish, turtles, etc.
• Benthos = bottomdwelling organisms
– Mussels, worms,
barnacles, etc
– Often are attached to
bottom surfaces
• Decomposers
Freshwater vs. Saltwater
Salinity = the amount of salt in water
• Salt water = marine ecosystems
– Coastal ecosystems
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Estuaries
Salt marshes
Mangrove swamps
Barrier islands
– Coral reefs
– Open ocean
• Freshwater = no salt
– Ponds, lakes & rivers
– Marshes and wetlands
Ponds and lakes
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No current
Levels are divided horizontally
by amount of light
and proximity to shore
Littoral zone: (think light)
– Lots of life
– Near shore, rooted plants provide food
– Off shore, phytoplankton are base
http://environment.nationalgeographic.com/
environment/photos/freshwater-plantsanimals/#/mexican-waterlilly_289_600x450.jpg
• Benthic zone: Bottom
– Decomposers (bacteria)
– detrivores (eat small bits of organic matter on bottom)
– Filter feeders
• Shrimp, clams, sponges, crabs etc.
Threats to Ponds and Lakes
Eutrophication (review)
1. Excess nutrients
enter water
2. Algae bloom,
overcrowd and die
3. Bacteria decompose
algae, using up
oxygen
4. Other organisms die
for want of oxygen
http://www.waterencyclopedia.com/A-Bi/Algal-Blooms-in-Fresh-Water.html
Prevention of Eutrophication (review)
Agricultural:
• Buffer zones between farms and waterways
• Control of runoff in areas of high manure
concentration
• High tech fertilizer application (only as-needed)
Eutrophication Prevention
Domestic
• Lawn-free landscaping
Eutrophication Prevention
Domestic
• Buy phosphate-free products
Eutrophication Prevention
Domestic
• Repair leaky sewer and septic systems
Rivers
• Dissolved oxygen increases with current
• Dissolved oxygen decreases with temperature
Wastewater vs. Stormwater
Sources of wastewater:
• Dishwasher
• Washer
• Sink
• Shower
• bathtub
• Toilet
• In short, anything that goes down the drain
Wastewater goes down sewer lines to a
wastewater treatment plant
Wastewater vs. Stormwater
Stormwater
• Water that collects outdoors and gets sent
into storm drains
• Catch basins are design to collect this runoff
Runoff
Catch basins take much more than storm
water
• Oils from cars
• Industrial chemicals
• Soil from construction sites
• Nonpoint-source pollution – cannot be
traced back to any single source
• Point source pollution: can be traced to
a specific source
Stormwater runoff
• Most stormwater goes directly to a waterway
Combined Sewer
• Stormwater and wastewater use same system
of pipes and get run to water treatment plant
http://www.epa.ohio.gov/dsw/cso/csoindex.aspx
Combined Sewer Overflow
• It works…until it rains hard
• In heavy rains, the combined stormwater and
wastewater overflow and go directly to the
waterways, polluting them
• CSO = combined sewer overflow
Combined Sewer Overflow Treatment
• Extra waste water treatment plant at point
where CSO runoff gets to waterway
• Stop-gap
Better solution:
• Separate sewers and stormwater systems
Permeability
• The ability to allow substances flow through
• A permeable surface allows rain to percolate
(seep) into the ground.
– Examples:
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Grass or other plants
Gravel
Dirt
Ground cover like pine straw or wood chips
Permeability
• Rain washes/flows over an impermeable (or
impervious) surface and does not get
absorbed into the ground.
– Ex:
• Rooftops,
• roads,
• parking lots
Permeability
permeable
impermeable
The more impermeable surfaces we have, the more runoff goes straight into the
waterways and takes pollutants with it.
Wetlands
Areas of nearly constant moisture that contain great
biodiversity
http://bio1152.nicerweb.com/Locked/media/ch52/aquatic-estuary.html
Freshwater Wetlands
two main types
Marshes
• Mostly non-woody plants
such as grasses, reeds and
cattails
Swamps
• Dominated by trees and
shrubs
Benefits of Wetlands
1. Filter pollutants
2. Control flooding
– Act as giant sponge, absorbing and slowing water as it
flows through
3. Buffer shorelines against erosion (absorb impact)
4. Spawning grounds, migration stop and habitat
for:
– commercially important shellfish and fish
– Native species (some rare, endangered)
5. Recreation
Wetlands: Human Impact
• Less than ½ of original US wetlands remain
• Causes of destruction include
– Ports (remember, wetlands are usually in estuaries)
– Development (NYC, Miami, Shanghai, New Orleans…etc)
– Dams, levees, canals, channels
– Pollution from runoff and wastewater
– Non-native plants and animals
– Sanitary landfills
– Mosquito control (drainage, channelization, poisoning)
• Channelization: digging channels/canals to drain
land
Wetlands: Human Impact
• Draining wetlands results in:
– Loss of benefits stated earlier
– Subsidence: ground sinks due to drying out
– Salt water intrusion: as wetlands are drained,
saltwater seeps in from ocean
• This is also a cause of further destruction (positive
feedback loop)
Wetland Loss Solutions
• Mitigation program:
– Creating wetlands in new areas to replace their
destruction for development (1983)
– Mitigation bank: sells newly created wetlands to
developers who have to mitigate
• Disallow wetland destruction
for agriculture (1985)
Wetlands: Estuaries
• Wetlands are often found in
estuaries: “where rivers meet
the sea”
– Large mostly flat areas
– Salinity changes with tides
• As tide comes in (gets higher),
salinity ↑
• As tide goes out (gets lower),
salinity ↓
Estuaries
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Nutrient mixing with tides
Salt water is ______ than fresh water
Heavier/denser
Due to tides and salt/fresh water mixing, nutrients
get “trapped” in estuaries.
http://www.wwu.edu/salishsea/estuary.shtml
swamps
Trees have “knees” or buttresses, probably for support in mushy ground
Saltwater swamps are mangroves
http://inchinapinch.com/hab_pgs/marine/mangro
ve/mangrove.htm
Freshwater swamp
Estuaries in Georgia
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Estuaries in Gulf of Mexico
Barrier Islands
• Protect mainland and coastal wetlands
http://geology.rockbandit.net/2008/09/15/how-barrier-islands-such-as-galveston-work/
Barrier islands take the brunt of storms
Tuesday, October 30, 2012
Superstorm Sandy: Tuesday
A Portion of Harvey Cedars on Long Beach Island, New Jersey is underwater Tuesday, Oct.
30, 2012, a day after Hurricane Sandy blew across the New Jersey barrier islands.
http://seattletimes.com/html/photogalleries/nationworld2019559529/
Coral
• Corals are invertebrate animals
– Heterotrophs
– Polyp = body of coral
– Stinging cells take in tiny organisms as they drift by
– Symbiotic relationship with algae called zooxanthellae
Corals and Energy
“autotroph” by day
• with help of zooxanthellae
Heterotroph by night
Because the corals rely on photosynthesis, they must live
in clear shallow waters
Corals – two types
• Soft Corals
– NOT reef building
– Include Sea fans and
feathers
• Hard Corals
– Reef building
– Add about ½ inch/year
– Uses calcium carbonate
from water
Coral Reefs
• Coral reefs are the limestone (Calcium Carbonate)
structures hard corals build
• Over thousands of years, each little animal’s
structure is added to the one below it
Coral Reefs: Locations
Concentrated in the tropical latitudes
Coral Reefs: Benefits
• On video
– Support wide biodiversity (40% of marine species)
• “tropical rain forest of the seas”
– Tourism & recreation
– Medicines and cancer drugs – still being explored
Coral Reefs: Threats
• On video
– Hurricanes (made worse by
– Boats
– Snorkelers/scuba divers touching corals
– Tropical fish pets
– Litter
– Water quality decreasing
• Pollution (bacteria, viruses, fungi causing diseases)
• Extra nutrients in water causing extra algae to grow,
blocking sunlight to zooxanthellae
– Changes in temperature due to global warming
– Ocean levels rising, blocking sunlight
Coral Bleaching
• Zooxanthellae provide the color in corals
• When the zooxanthellae get ejected from
corals, they are left colorless, “bleached”
Coral Reefs: Solutions
• On video
– Moorings for boats so that they don’t drop anchor
on reefs
– Education
• Instruct snorkelers and scuba divers on how NOT to
disturb reefs
• General Public awareness
– Beach cleanups
– Decrease burning fossil fuels
– Decrease use of fertilizers
– Decrease pollutants (litter & other)
– Repair and improve wastewater treatment
Ocean Acidification- cause and effects
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↑ CO2 in atmosphere
↑ CO2 diffuses into water
↑ water acidity
↓ available carbonate ions
↓ reef building and health of pteropods and
other shell-building organisms
• PS This happens in large lakes too.
http://www.pmel.noaa.gov/co2/story/Wh
at+is+Ocean+Acidification%3F
Ocean Acidification – bottom line
• Reefs are directly
affected by increased
CO2 in atmosphere
• Entire ocean food web
also in jeopardy due to
increased CO2
• ocean acidification film
clip: (21:35 minutes)
http://www.nrdc.org/oce
ans/acidification/aboutth
efilm.asp
http://theoceanproject.blogspot.com/2012/03/ocean-acidification-osteoporosis-of.html
Biological Pump
– Algae use CO2 in photosynthesis
– This ↓ CO2 in the water
– That ↑ amount of CO2 diffusing into the water
from the atmosphere
– Which ↓ the amount of CO2 in the atmosphere
– Win-win!
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CO2
Solubility Pump
• Which holds more CO2?
warm or
cold Coke?
• S.P. = The idea that warm water holds less
dissolved gas than cold water
• As ocean currents carry warm water to colder
regions, the water absorbs more CO2 from the
atmosphere
Other Threats to Oceans
• Overfishing
• Eutrophication
• Trash/litter
• Garbage TED talk (7:23 minutes)
• http://www.ted.com/talks/capt_charles_moore_on_
the_seas_of_plastic.html
• good Morning America ABC: (4:31 minutes)
• http://www.youtube.com/watch?v=WtewmJ78hzw