Transcript Oceans Student Questions.ppt

Student Questions
about Oceans
What should you know about
corals?
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They are animals
Plants live inside of
them
Two kinds
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Soft corals
Hard corals (These build
reefs!)
They are made of tiny
polyps (which look like
upside-down jellyfish)
What does it mean to be a
coral?
Almost all corals are colonial organisms.
 This means that they are composed of
hundreds to hundreds of thousands of
individual animals, called polyps (Barnes, R.D.,
1987; Lalli and Parsons, 1995).
 Most corals feed at night (Barnes, 1987).
 Nematocyst-stinging cell (e.g. Jellyfish).
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A coral's prey ranges in size from nearly
microscopic animals called zooplankton to small
fish, depending on the size of the coral polyps.
Corals
Landlords of the Reefs
Soft Coral
Hard Coral
Hard Corals
The Reef Builders
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Polyps build hard
limestone cups around
their bases
The cups cement
together to make a
coral colony
Reefs are made of
hundreds of hard coral
colonies next to and on
top of each other
What’s a Polyp?
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Tentacles release
stinging cells when
something brushes by
them
Polyps make their own
limestone cup to hide in
during the day
At night, polyps come
out to catch plankton
floating by.
Anatomy of Coral
Zoo-what!?!
Algae, Coral Polyps’ Tenants
Inside polyps live zooxanthellae, which
are algae.
 Zooxanthellae give corals their color.
 Since algae are plants, they use
sunlight and CO2 to make food (the
process known as photosynthesis).
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Zooxanthellae
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Most reef-building corals contain
photosynthetic algae, called
zooxanthellae, that live in their tissues.
The corals and algae have a mutualistic
relationship.
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The coral provides the algae with a protected
environment and compounds they need for
photosynthesis.
In return, the algae produce oxygen and help
the coral to remove wastes.
Zooxanthellae
Zooxanthellae
The relationship between the algae and coral
polyp facilitates a tight recycling of nutrients in
nutrient-poor tropical waters.
 In fact, as much as 90 percent of the organic
material photosynthetically produced by the
zooxanthellae is transferred to the host coral
tissue (Sumich, 1996).
 This is the driving force behind the growth and
productivity of coral reefs (Barnes, 1987;
Levinton, 1995).
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Coral reproduction
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Asexual reproduction
(usually in branching
corals; often stormrelated)
Sexual reproduction
Hermaphroditic or gonochoristic
Self- or cross-fertilization
Internal or external fertilization
Brooders or broadcast spawners
Richard Fitzpatrick
Bette Willis in J.E.N. Veron
(1987) Corals of Australia
and the Indo-Pacific.
Hawaii University Press
Brooders
Eggs develop into larvae
internally and may be
brooded for several weeks
 Larvae are released, often
at night, often in response
to the lunar cycle
 Brooders may have up to 12
reproductive cycles per year
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R. Hays Cummins
Coral larvae (planulae)
Swim using tiny hairs (cilia)
 May already contain
zooxanthellae
 Swim for days to weeks before
they settle and
metamorphose
 Settlement may be in response
to chemical cues and may be
gregarious
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Bob Richmond
NOAA
Fringe Reefs: Diving anyone??
Growth on reefs are often limited by tidal
action.
Disease is another major factor limiting growth.
Here is an example of elkhorn coral (Acropora
palmata) infested by “white band disease.”
Barrier Reefs
An excellent example of a Pacific barrier
reef.
Barrier reef structure can be influenced by
spur and groove formations such as these.
The Great Barrier Reef
Atoll Reefs: Volcanic Left-overs!
Atoll Formation: Step by step
Reef Ecology: Edge effect again…
Food Webs: Same concept, more
complexity
Coral Fights??
Yes!
Just like other animals competing for space, coral attack
each other if they come into close contact.
Usually they just over grow one another, but some
actually poison the others out!
Again, we see that real estate is at a premium with
these soft corals. Soft corals are fast growers,
making them excellent competetors.
Harmony? Not really, most animals on reefs
compete daily for everything, from food to mating
opportunities.
Artificial vs. Natural Reefs
Status of coral reefs
Globally, coral reefs are generally in
decline
 Increasing human population
(especially in coastal areas) increases
the impacts on coral reefs
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Human impacts on coral reefs
 Overfishing
 Sedimentation
 Nutrient
enrichment
 Chemicals/oil
 Physical damage
(anchors, fishing,
groundings)
Overfishing
Changes trophic structure
 Many large predators are no
longer present
 Grazing fish species are
being collected as food fish
 May allow algal overgrowth
of corals
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NOAA
Without proper
light and temperature,
coral dies (bleaches).
It only takes 1-2 degrees
in some cases.
How does climate change
effect this trend?
From this…
To this….
Temperature increases and competition from red algae have killed
much of this coral reef.
HAB’s/Red tides
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Blooms of “harmful algae”
Pfisteria
 Cause human health
problems
 Cause fish kills
 May be killing dolphins,
manatees
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Mote Marine Lab
FMRI
Effects of increased nutrients
on corals
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Cause decrease in coral
growth
Direct chemical
interference with skeleton
formation
 Result of overshading by
algae
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Jennifer M. Smith
The nutrient-calcification
mystery
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If zooxanthellae help corals calcify,
then why do enriched corals, which
contain more zooxanthellae, calcify
less?
Zooxanthellae are N-limited
 “Excess” photosynthate is given to coral
 If zooxanthellae grow, there is less
photosynthate to give to the corals
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But….
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There are more zooxanthellae per cm² of
coral, so the animal receives the same
amount of carbon…
=
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Is the type of carbon compound different
in enriched and control corals?
Chemicals/oil
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Non point-source pollution
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51% of the oil entering the oceans is from
runoff
5% is from big spills
19% is from routine maintenance
2% is from offshore drilling
13% is from burning fuels (e.g. car exhaust)
10% is from natural seeps
Physical damage
Thomas Heeger,
Philippines
Fishing techniques in the South Pacific
include dynamiting or poisoning reefs to
collect aquarium fish for export
 Boat anchors and boat/ship groundings
cause damage that can take thousands
of years to re-grow
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Natural impacts
Marine debris
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Suffocation risk
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Balloons/bags
Entanglement/entrapment
Fishing line/ropes
 Old nets
 Abandoned traps/pots
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What can you do?
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Reduce, reuse, recycle
Motor oil
 Fishing line
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Read and follow instructions
on chemicals, including
fertilizers
 Fix automotive leaks
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Fish
The most diverse and
successful vertebrates
20,000 spp.
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Agnatha:
jawless fish,
lampreys and
hagfish
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Condrichthyes:
cartilaginous fish,
sharks and rays
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Osteichthyes:
bony fish
Three Classes
of Fish
Lateral line system
Fluid filled canals along sides of fish that detect
movement and vibrations in water
Three Classes of Fish
Agnatha: jawless fish,
lampreys and hagfish
 Class Condrichthyes:
cartilaginous fish, sharks
and rays
 Osteichthyes: bony fish
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Agnathans:
jawless fish
Cartilage
skeleton
 Parasitic
bloodsuckers
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Lamprey
Sucker-like mouths
 Attach to another
fish, scrape away
flesh and then suck
blood.
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Slit-like, toothed
mouth
 Drills holes and
sucks blood of dead
or dying fish
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Ha
g
f
i
s
h
Chondrichthyes:
Cartilaginous fish
 Entire
skeleton is made of cartilage
 Living
fossils
 Include:
 Sharks
 Rays
 Skates
Sharks
Some (sharks) have internal fertilization.
There are three ways that sharks can be
born:
 eggs
are laid (like birds)
 eggs hatch inside the mother and
then are born
 Shark pups grow inside the mother
(like humans)
Shark Diversity
Shark Diversity
Megachasma pelagios
Squaliolus laticaudus
Pygmy shark
megamouth shark
Shark Diversity
Whale shark
Goblin shark
Mitsukurina owstoni
Rhincodon typus
Ampullae of Lorenzini
Sharks
Have been around for 400 million years
 Almost unchanged for 150 million years
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Bites prey, then
tears it apart by
tossing head back
and forth
 Rows of backup
teeth replace lost
ones
 May grow and use
20,000 teeth in a
lifetime
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Shark Teeth
5 Most Dangerous Sharks
Hammerhead
Great
White
Tiger
Mako
Bull
shark
Great White Shark
Up to 3000 teeth at one time
 Up to 23 feet in length
 Feed on sharks, sea lions, fish, rays, whales
 Account for 1/3 to ½ attacks on humans
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Tiger Shark
Will eat fish, turtles, crabs, clams, mammals, sea
birds, and other sharks. Occasionally Attack humans.
Hammerhead
Shark
From 12 – 20 feet long
 Unlike other sharks, they
form schools
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Mako Shark
The fastest shark, and among the fastest
fish
 Feed on schooling fish
 Dangerous, with many attacks on people
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Bull Shark
Because it is
aggressive and
swims in shallow
water, is frequent
attacker of people
 Swims close to
shore and can live
in fresh water
rivers and lakes for
awhile
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Largest sharks AND largest
fish
 Up to 46 feet long and 15
tons
 Filter feeders – eat mostly
plankton and krill
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Whale
Sharks
Senses
Over 2/3 of a shark’s brain is dedicated to smell
 Can feel vibrations in the water
 Sharks can
use smell to
follow a trail
of blood for
several km
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Rays
Flat bodies
 Broad pectoral fins on sides
 Glide by flapping fins
 Feed on mollusks and
crustaceans on ocean floor
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Offenses and defenses
Sharp spines with poison
glands.
 Electricity to kill
predators and prey.
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Above: electric ray; Right, top:
stingray barb; right: barb in
foot
Skates
Skates
 Stocky tail with no stinging spine
 Two lobes on pelvic fin
 Thorn-like scales on midline of back
and tail
Rays
 long tail with stinging spine at midway
 Single lobes on pelvic fin
 No thorn-like scales
Osteichthyes –
Bony Fishes
The largest group (superclass)
 Skeleton is made of bone
 Three classes:
 lung fish
 Lobe-finned fish
 Ray-finned fish
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Lobe-finned
Fish
Only one species: the
coelacanth
 Fins adapted to
crawling
 Pre-cursor to
amphibians
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Coelacanth
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Scientists thought the coelacanth had gone extinct with the
dinosaurs.
1938: a specimen was found at a local fish market
Scientists now know that the coelacanth has remained alive,
and unchanged for 400 million years.
Ray-finned Fish
Fan shaped fins with stiff spines (rays)
 Fins adapted to swimming
 Huge diversity: Catfish, salmon, perch….
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Ray-finned fish that
can walk on land
Walking catfish
 Mudskipper
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Inflatable
Fish
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Porcupinefish:
When threatened, swell
by filling body with water
Become too large for the
predator to swallow.
Spiny covering is another
defense.
Pufferfish:
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Inflates when threatened
Large black spot near the
tail draws predator’s
attention away from the
its head and allows
Toxic Fish
The Beautiful
Lionfish:
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Sharp spines are coated
with a poisonous mucous
Capable of delivering a
painful sting.
The venom of some is
strong enough to kill a
man.
The Ugly Stonefish:
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stone-like appearance is
an excellent camouflage
Has sharp, venomous
spines that contain enough
poison to kill a man.
Sea Horses
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Male seahorses carry fertilized eggs in a special
abdominal pouch until they hatch.
each day a seahorse can consume up to 3,000 brine
shrimp
seahorses have no teeth and swallow their food whole
Dangerous Fish
Moray Eel:
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one of the largest eel species.
feed mainly on fish.
razor sharp teeth
can remove the fingers of
divers.
Electric Eels:
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Electric eels are not true eels.
They are related to catfish and
carp
found in South America.
Electric eels produce more
electricity than any other living
creature.
Can disable a cow, stun a man
or horse, light a neon lamp, or
drive a small motor.
Hidden Fish
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Leafy Sea Dragon:
species of seahorse
camouflaged by leafy extensions
which resemble seaweed.
feed mainly on small shrimps
Scorpionfishes:
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camouflaged by bizarre
appearance
Use camouflage to ambush prey
numerous venomous spines cover
their bodies.
Fish that ‘fish’
Frogfish:
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camouflaged by appearance.
modified dorsal spine with a
fleshy growth at the end.
lie motionless and use this spine
like a fishing rod.
curious fish are swallowed up by
large, powerful jaws.
Anglerfish:
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lives deep on the ocean floor
eats crustaceans and smaller
fishes.
uses a bioluminescent lure on
the end of its "fishing pole".
Lure resembles bioluminescent
bacteria which other fish eat.
Above: frogfish;
Left and below:
anglerfish
Flying Fish
Flying Gurnards
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large, wing-like pectoral fins.
do not actually fly.
Their large fins help them to swim low over the sand as
they search for food.
Atlantic Flying Fish
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large pectoral fins and long tail fin
"leap" or "glide" like flying squirrels over the water surface.
Deep Ocean
Fish
Angler fish, Hatchet fish,
viper fish
Pacific Bobtail squid
 Deep sea glass squid has
light organs on its eyes
and can roll into a ball
like a hedgehog when
threatened.
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Deep sea
Squid
Hydrothermal Vent Species
Some vent species feed on the
chemicals emitted. Others, like
the octopus, feed on small
creatures living near the vent.
Two tubeworm species;
hydrothermal vent octopus
Luminescence in
the Deep
-Bioluminescence is light
produced by a chemical
reaction which originates
in an organism.
-Very common in the
ocean
Warty Anglerfish with a
luminescent lure; Deep-sea
lizardfish with luminescent eyes
Orange Roughy
Live to be 150 years old
 Don’t reproduce until 25 or 30 years old
 Live up to one mile deep
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