1.
ASSIGNMENT PRESENTATION OF
LIMNOLOGY
TOPIC- PLANKTONIC ORGANISMS
AND
CLASSIFICATION

2.
PLANKTONIC ORGANISMS & CLASSIFICATION
• What are planktons?
• Diverse group of organisms living in large water
bodies.
• Unable to swim against water currents.
• They provide a crucial source of food to large aquatic
organisms.
• Includes bacteria ,algae, archaic, protozoans &
drifting or floating organisms.

3.
• Found in pelagic zone of water bodies.
• Essentially, they are defined by their ecological niche.
• They are of wide ranges of sizes, including some
microscopic organism & large organisms such as jelly
fishes.

4.
CLASSIFICATION
PLANKTONS are classified into following group on
The basis of their origin-
• PHYTOPLANKTON
• ZOOPLANKTON

5.
PHYTOPLANKTONS
• Derived from Greek word ‘python’ meaning plant.
• Commonly are algae.
• They are eukaryotic or prokaryotic algae.
• They live near water surface where there is sufficient
amount of light energy for photosynthesis.
• Among the more important groups are diatoms, cyan
bacteria, dinoflagellates and coccolithophores.
• Inhabit upper sunlit layers of water bodies called
euphotic zone.

6.
• They are coloured due to presence of chlorophyll &
acessory pigments such as phycobilliproteins &
xanthophylls.
• They are agents for "primary production” in aquatic
food web.
• Phytoplankton productivity is affected by changes in
the vertical stratification of the water column, the rate
of temperature-dependent biological reactions, and
the atmospheric supply of nutrients .

7.
PHYTOPLANKTONS AND
AQUACULTURE
• They are a key food item in aquaculture &
mariculture.
• Planktons are used as a food stock for the production
of rotifers which are in turn used to feed the
organisms.
• The production of phytoplankton under artificial
condition is itself a form of aquaculture.
• The majority of cultured plankton is marine.

8.
ZOOPLANKTONS
• They are hetrotrophic sometimes detritivorus
plankton.
• The word zooplankton is derived from the Greek
zoon meaning animals & planktons meaning
wanderer.
• Although they are transported by water
currents,many have locomotion, used to avoid
predators.
• They are both holoplanktons & meroplanktons.

9.
• Zooplanktons feed on bacterioplanktons or
phycoplanktons.
• They are found in surface water where food
resources are abundant.
• The physical factor that influences zooplankton
distribution the most is mixing of water column that
affects nutrient availibility & in turn phytoplankton
production.
• EXAMPLE
• Rotifers, krills , radiolarians & pteropods.

10.
CLASSIFICATION
• On the basis of their cell size they are classified into
following groups-
• Bacterioplanktons
• Nanoplanktons
• Microplanktons
• Macroplanktons

11.
BACTERIOPLANKTONS
• They are less than two microns.
• Smallest phytoplanktons are represented by this
group.
• Example-
• Bacillus , micrococus & bacterium.

12.
NANOPLANKTONS
• Size ranges from 2-20 microns.
• Smaller phytoplanktons belong to this group.
• They are flagellates.
• Example-
• Cocolithus & Gymnodium.

13.
MICROPLANKTONS
• Size ranges from 20 to 200 microns.
• Large phytoplanktons & small zooplanktons belong
to this group.
• Example
• Dinoflagellates- Ceratium & Dinophysis.
• Diatoms- Chaetocerus

14.
MACROPLANKTONS
• Size ranges from 200 to 2000 microns.
• Visible by naked eyes.
• They includes copepods.
• Example-
• Calamus , Euphasia Superba (Antartic krills)
• Antartic krills are food for whales.

15.
Euphasia superba (Antartic krill)

16.
MEGAPLANKTONS
• They are exceptionally large organisms.
• They are larger than 2000 microns.
• Body posses tentacles which are quite long
(15 m).
• Example
• Physalia