3. Two types of Plankton
1. PHYTOPLANKTON
- singled-celled autotrophs
- Foundation of the aquatic food
web as it is the primary source of
energy for the next trophic level
- include the dinoflagellates,
diatoms, coccolithoporids, and
cyanobacteria
2. ZOOPLANKTON
- Heterotrophic organisms
- Capable of movement, but not
capable of making their way
against a current.
- E.g. copepods, fish larvae,
medusae, chaetognaths, etc.
11. A comparison of food chains
in three different marine
habitats.
The organisms representing
each trophic level are only
selected examples of the
many marine species that
could be present in that level.
(Organisms not to scale.)
12. TYPES OF PHYTOPLANKTON
• Unicellular algae that occur mostly as single cells
but some species are colonies
• All species have an external skeleton, called
frustule, made of silica; this glassy shell or frustule
consist of 2-tightly fitting halves
• Major group of algae, and are among the most
common types of phytoplankton
• Cell size ranging from about 2 µm to over 1000 µm
• Two types of diatoms are recognized: Pennate and
Centric forms.
1. DIATOMS
Pleurosigma sp.
Achnanthes sp.
Chaetoceros
diversus
Coscinodiscus
sp..
Centric forms
Pennate forms
13.
14. TYPES OF PHYTOPLANKTON
• 2nd most abundant phytoplankton group following the
diatom
• Possess two flagella, or whip-like appendages and are
therefore motile
• Dinoflagellates may be Autotrophic, Heterotrophic and both
(Mixotrophic)
• Theca plates (thick cellulose)
• Some common unarmored “naked” representatives:
Gymnodinium, Cystidinium, and Glenodinium
• Some are armored (thecate) species: Peridinium, Ceratium,
Dinophysis, and Gonyaulax
2. DINOFLAGELLATES
15. 3. COCOLITHOPHORIDS
• Unicellular algae common in warm tropical waters
• External shell composed of a large number of
calcareous plates called coccoliths.
• Possess two flagella, although they may have a
life cycle which includes an alternation with a
non-motile stage lacking flagella.
• There deposits were formed from coccoliths that
sank to the bottom of warm, shallow seas during
the Cretaceous geological period. It became the
largest reservoir of carbon on Earth.
TYPES OF PHYTOPLANKTON
16. 4. SILICOFLAGELLATES
• Best known marine forms of the Chrysophyceae, or
golden-brown algae
• with an internal skeleton formed of siliceous
spicules
• Uniflagellate organisms are small (10-250 µm) and
contain very numerous yellow-brown chloroplasts.
• Most abundant in colder waters.
TYPES OF PHYTOPLANKTON
17. 5. CYANOBACTERIA
• Blue-green algae or blue-green bacteria
• Single long filaments formed by chains of cells
• Capable of utilizing and fixing dissolved gaseous
nitrogen (N2),
• Occurs abundantly in the euphotic zone of both
coastal and oceanic waters of temperate and
tropical oceans.
TYPES OF PHYTOPLANKTON
27. Plankton Counting
• A ratio system has been developed to estimate the
total number of plankton in given volume of water.
This technique is called Cell Counting and is done with
a device called Haemocytometer.
• With this device a sample of water is placed on the
slide that has a very small grid on it.
