WHAT IS PLANKTON?
• Animals and plants that
either float passively in the
water, or possess such
limited powers of swimming
that they are carried from
place to place by the
• “ Plankton ” is not a single
species but a large group of
The word plankton comes from the
Greek word planktos, which means
‘wandering’ or ‘drifting’.
Types of Plankton -
plants and bacteria.
Phytoplankton are photosynthetic
autotrophs, who begin all marine food
• Produce 50-90% of all atmospheric
oxygen, and are critical biomass.
• They are adapted to a floating lifestyle.
• Phytoplankton don’t have roots , stems
or leaves. But like land plants , they are
able to capture sunlight and convert it
• Each phytoplankton is a single cell or a
chain of cells.
• Phytoplankton live near the surface of the
ocean close to the sun because they need
sunlight to make food.
• The shape of the phytoplankton keep them
from sinking to far below the surface of
Some important types of phytoplankton &
where they found
•Diatoms: temperate and polar waters, silica case or
•Dinoflagellates : tropical and subtropical waters....
also summer in temperate
•Coccolithophores : tropical, calcium carbonate shells
•Silicoflagellates : silica internal skeleton... found
world wide, particularly in Antarctic
•Cyanobacteria (blue-green algae): not true algae,
often in brackish nearshore waters and warm water
•Green Algae: not common except in lagoons and
The primary consumers,
in food webs.
• They are the smallest
and most numerous
• Their population density
depends on the
which they graze.
How are phytoplankton different from
• Single cells or chains of
including the smallest
plankton – picoplankton
• Remain near the surface
• Consumers (including
• Include microscopic
• May vertically migrate
(to a depth of 200m)
during the day for
resurface at night to
• Important part of global
• Food source (basis of the
• Producer of oxygen
Why are plankton important?
Where are plankton found?
Plankton dominates the well-lit
surface layers of the world's oceans.
How are plankton studied?
• Collected with special
and sampling bottles
• Underwater cameras
Bongo nets may be towed over the side of the ship to collect
Plankton are an energy source for marine ecosystems
• Many plankton are primary producers
• Over 90% of marine primary production (energy
produced) is from phytoplankton . The rest is
from marine plants and other sources.
• This map shows
productivity in the
• Red and yellow are most
productive, followed by
green and blue.
Black is least productive.
Accessed: November 2010
Satellites can also help scientists study plankton
• Satellites equipped with
colour scanners measure
the concentration of
chlorophyll in the ocean
• Red and orange indicate
higher concentration of
chlorophyll, while blue
and green represent
• Chlorophyll is an indicator
of plankton and can be
used to study plankton
populations Satellite image of the Gulf of Maine,
Photo: NASA Earth Observatory Collection,
These are the primary food for most of the
aquatic animals, e.g.:- whale
They autotrophic help in CO2 fixation means
help in the carbon fixation,
Because of these activity our oceans called as a
They make there food by the photosynthesis,
They produce oxygen 50-90%,
Small but important player of the earth
A bongo net is a metal frame with two paired mesh nets attached (see photo on slide). They are named “bongo nets” because they look somewhat like bongo drum. For more information, see: http://www.whoi.edu/page.do?cid=11254&pid=8415&tid=282; Accessed: November 2010.
A video plankton recorder is a form of underwater microscope that takes images of plankton for study while a boat is moving. The advantage is the ability to sample plankton quickly over a large area. For more information see: http://www.whoi.edu/instruments/viewInstrument.do?id=1007; Accessed: November 2010.
NOAA Photo Library
Image ID: fish1014, NOAA's Fisheries Collection Photo Date: 1987Photographer: Captain Robert A. Pawlowski, NOAA Corps