Transcript Photic Pelagic Waters

Photic Pelagic Waters
I. Location
A. From surface to 200m (average)
B. Where photosynthesis takes
place
II. Environmental Characteristics
A. Sunlight
1. Plenty of sunlight
2. Where most oxygen for
planet is produced
3. Wide variety of
photosynthetic organisms
B. T
1. Much warmer than deep sea (for
the most part)
2. Changes from day to day
(sometimes within the day)
3. Has seasonal changes (warm
during summer, cooler during
winter)
4. Varies from place to place
C. Pressure
1. Upper photic – not much
2. Lower photic – bit more, but
nothing like the deep sea
D. O2 - #1 producers of oxygen, so
plenty
E. Food – Not a problem; more food
than anywhere else
F. Habitat
1. Surface water is in constant
motion – waves, tides and
currents
2. Really no place to hide or rest –
open water
3. Can’t rest for long – will be
eaten or starve
III. Importance of Photic Waters
A. All primary productivity for
ocean occurs here
B. Start of the basis of the
marine food chain
C. Place where humans like
D. Richest part of the ocean
IV. Types of Organisms
A. Plankton – organisms at the mercy
of the ocean; drifters
1. Phytoplankton – planktonic plants
plants at the mercy of the ocean
a) Basis of the marine food chain
b) Photosynthetic - #1 producers
Diatoms
of oxygen
c) Most microscopic
–
diatoms,
dinoflagellates
dinoflagellates; Protistas
d) Seaweed & kelp – true plants at
mercy of ocean
e) Without phytoplankton – NO LIFE
f) Produce more oxygen than
anything else
Where did the
phytoplankton
go!!?
2. Zooplankton – planktonic “animals”
Mola mola
a) Most microscopic – copepods,
larvae of many invertebrates
(crab, shrimp)
b) Some mega plankton –
jellyfish, sunfish (one of
largest fish in sea)
c) Second step in the marine
food chain
B. Nekton – directed swimmers,
NOT at the mercy of the ocean
1. Includes all vertebrae marine
life, fish, adult
invertebrates
2. Must have special adaptations
to live in “open” waters
3. Most nekton “hydrodynamic” –
streamlined to move through
water easily, fins
retractable, eyes flushed
with head, powerful tails
4. There is more nekton then any
other type of animals (except
insects)
V. Two Very Important Phytoplankton
and One Zooplankton
A. Diatoms – unicellular, microscopic
algae (phytoplankton)
1. Looks like a “petri dish”,
usually a golden-brown color
2. No means of locomotion
3. Made of silica -> makes
siliceous ooze
4. Feeds over half the marine life
5. Millions upon millions throughout
every ocean
6. Probably most important
organism on this planet
B. Dinoflagellates – unicellular,
microscopic algae; phytoplankton
1. Has locomotion – flagella ->
“whip like” projection
2. Causes red tides - a massive
killing of marine life
a) Dinoflagellates suddenly
multiply in large numbers –
millions & millions
b) They have a toxin that
poison and suffocates marine life
c) In such large numbers,
the dinoflagellates tint the water
red -> red tide
d) DO NOT EAT OYSTERS,
FISH, OR CLAMS DURING A
RED TIDE!!!
e) Have been known to harm humans
(Not attacked, but swallowed)
C. Copepods – microscopic, shrimp
like zooplankton
1. Feed on phytoplankton
2. Second step in marine food
chain
3. Filter feeders
4. Most have bioluminescence
5. Have adaptations to keep from
sinking into “Death Zone”,
below the light
VI. Adaptations of Photic Water
Organisms
A. Main goal is to stay in the
photic zone – fall below will
die (T, Pressure, no food)
B. Many have “projections” – fins,
hair, spines, etc
1) Increases surface volume
of “body”
2) Slows sinking rate
C. Body shape
1) Most are flat – easier to stay
afloat
2) Streamlined – move through
water fast;
3) Extra fat – blubber -> help
larger animals stay afloat
4) “Air” bladder – many fish,
allows them to stay
“suspended”
D. Coloring
1) Counter-shaded -> dark on
top, light on bottom, blends
in with environment
2) Striping – dark, light banded
– blends with wave action
3) Plankton – usually brownish
or clear (hard to see)
4) Some brightly colored – “coral
reef” blending
5) Nekton – generally silver, gray
E. Speed
1. Nekton – usually very fast, if
not will be eaten or starve
2. Plankton don’t have to worry
F. Defense
1. Being big or very small
2. “Swim in schools”
3. Being fast
4. Coloring - hard to see
VII. The Benthos Organisms
A. Benthos – organisms that live in
or on the bottom of the ocean
B. Includes – crabs, clams, sea
stars, barnacles, snails, octopus,
some fish, coral, etc…
C. Three Types
1) Epifauna – live on top of
the ocean floor
2) Infauna – lives in or
burrow into the sediments
of the ocean floor
3) Sessile – permanently
attached; like barnacles
D. Most benthos on continental shelf
E. Harsh environment
1) Constant changes in salinity
levels
2) Constant and heavy waves,
currents & tide action
3) Constant change in water T
4) “Home” constantly moving
(unless on rocks)
F. Adaptations
1) Excellent burrowers – can dig
in sediments very fast
2) Usually have a “shell” for
protection (keep from
getting crushed – waves,
seds)
3) Cryptic coloring – can change
or “patterned” after
sediments
4) Some have great “stick ‘um”
power – cling to rocks, etc,,
5) Special feeding lots of food in
this area; mostly tiny “particles”
a) filter feeders -> “rake in”
food particles (usually with
antenna or “hands”)
b) siphon feeders -> “siphon” in
water with food particles
c) detritus feeders – feed on
small particles of decaying
matter
VIII. Miscellaneous
A. The photic zone is a vast area
B. Includes many species of
organisms
C. Variety of adaptations, colors,
sizes, etc…
D. 99% of all studies in the ocean
are in the photic zone
E. Still many unanswered questions
F. Without the photic zone, there
would be NO LIFE!
IX. Importance of the photic waters
A. Start of food chain
1. primary productivity – energy
that comes from
photosynthesis
2. #1 producers of
photosynthesis –
phytoplankton
3. 20% of the phyto sink below
the photic zone & die
4. the sinking of dead organisms is
called detritus
5. 90% of food for benthic comes
from detritus
6. about 95% of all marine “food”
begins in the photic zone
7. Without phytoplankton = no life
B. Nutrients not found readily in
photic zone
1. Nutrients needed to help go
through photosynthesis
2. most nutrients found below
photic zone
3. need a nice mixing of waters
a. upwellings – a current that
brings nutrients from
the deep to the surface
b. winter mixing – surface
waters become colder & sink
1) this forces nutrients to
surface
2) excellent winter mixing in Gulf
of Mexico – very productive
3) the tropics & the polar regions
– not very good mixing
leads to poor primary
productivity – but clear
waters
C. Factors that affect primary
productivity
1. Types of organisms – more
phytoplankton = more “food”
2. Sunlight – needed for
photosynthesis
3. T & seasons – affects
amount of nutrients
4. Amount of nutrients – can’t
live on sunshine alone