Standing on the Shoulders

1
Standing on the Shoulders of Giants Plankton a
t the Base
of the Pyramid
2
(almost) All life depends on transfer of solar
energy
This is done by autotrophs (life that
makes its own food)
Autotroph plant!!
All animals are heterotrophs (life depends
on other life for its food)
Heterotroph YOU!
3
Todays focus plankton ( wanderers)
Plankton are floating, drifting organisms
4
Plankton refers to lifestyle, not a life form.
Phytoplankton group of planktonic
organisms that are AUTOTROPHS
Function like plants - photosynthesize
(or in a few cases, chemosynthesize)
What do plants need for photosynthesis?
5
Remember, chemical equation for photosynthesis
6 H20 6 CO2 solar energy-- C6H12O6 6 O2
Inorganic nutrients (P,Fe,S) - these are neede
d for the protein molecules that facilitate pho
tosynthesis in the cells.
6
Water lots of it in ocean!
Carbon dioxide lots of it because
highly soluble in water
Light this is tricky because it requires
certain wavelengths for photosynthesis
AND minimum intensities
look further at light.
7
Phytoplankton are found in the photic zone
in the upper part of the ocean.
8
Different wavelengths penetrate to different
depths
what we mean is that all wavelengths other than
blue
get absorbed in the water above 100 m
9
Why is this important?
10
Chlorophyll is the most common
chemical for photosynthesis and it appears
green
11
The red and violet wavelengths do not
penetrate very deep into the ocean
12
This means that most photosynthesis
takes place within the upper 100 m.
Some plants adapt by using xanthophyll,
a photosynthetic pigment that is brown
or yellow.
13
An additional complication phytoplankton are A
LIVE!
This means that they also USE energy.
Some of the sugar they make with
photosynthesis has to be used by
them to live.
14
Thus, light is only sufficient in upper 60 m of
ocean!
15
Put in notes
Only blue light penetrates into the
water more than 100 m, so most
photosynthesis takes place in the
shallowest part of the ocean where
there is sufficient red and violet light
for chlorophyll to work. Other
photosynthetic pigments will allow
photosynthesis to work up to 60-90
m (200-300 ft) depth, but the light is so
weak that phytoplankton use more sugar
than they make below depths of 60 m (200 ft).
16
Primary productivity in the ocean is a
surface feature.
This accounts for 40 of the carbohydrates made
by all primary
producers (autotrophs) each year.
Land 60 Ocean 40
Also, phytoplankton make 40
of oxygen each year!
17
Summary phytoplankton limited to
shallow waters of ocean.
If in shallow water, then enough water,
carbon dioxide, light. WHATS LEFT?
Inorganic nutrients!
Inorganic nutrients are the limiting
factor in the growth and distribution
of phytoplankton
18
Inorganic nutrients are depleted
rapidly by phytoplankton unless
they are replenished.
WHERE DO THEY GET REPLENISHED?
Regions of upwelling
Near continents
19
Regions of upwelling occur where the
thermocline is weak or nonexistent
Polar regions, esp. Antarctica!
20
Near continents because of greater light in sprin
g and runoff
21
Chlorophyll concentration in late spring
22
So, what exactly do phytoplankton look like?
Tiny!!
Diatomsmost common type
smaller than a period (0.1 mm)
shells made of SiO2 (same composition as glass)
silica is source of deep ocean sediment
23
Diatoms have to float in the upper
3 m of water (because they use lots
of red light), but they are making a
silica shell that is heavy.
How do they float?
Instead of saving the photosynthesis
products as sugar, they convert them
to fatty acids and oils.
Oil floats on water! (so the diatoms are buoyant)
.
24
Dinoflagellates -- another major type of
phytoplankton
they have little whips called flagella
to move and orient themselves
to maximize light
25
Dinoflagellates are bioluminescent
Video courtesy of MAR-ECO
26
Dinoflagellates are also responsible for red ti
des, a type
of harmful algal bloom.
These can produce a strong neurotoxin that kills
fish and shellfish (AND the people who eat th
em!)
27
Some plankton are primary consumers
(heterotrophs that eat primary producers)
These are called zooplankton (animal plankton)
28
The most important zooplankton is
krillsmall, thumb-sized arthropod
Primary food source in Antarctic oceans
for birds, fish, squids, whales --
LARGESTBIOMASS OF ANY ORGANISM!!
29
Baleen whales use filters to strain water
and mud for krill
One of the largest animals lives off one of the

smallest
30
However, YOU do not see much evidence
of the base of the food pyramid!
The more obvious evidence of primary
producers in the ocean (but only contributes
2-5)
31
Seaweed are algae!
Algae are mostly unicellular but seaweed is mul
ticellular.
Seaweed are green (chlorophytes) brown
(phaeophytes)
red (rhodophytes)
Kelp! Most common
Remember light penetration and pigments!
32
Mangrove trees can live in SALT water
33
Mangroves are very important because
they bind soil and provide habitat for
many other organisms
(Florida mangrove swamps)
34
Next time