This document discusses the classification of planktonic organisms. It defines plankton as diverse microscopic and small organisms that live in water bodies but cannot swim against currents. Plankton are classified into phytoplankton and zooplankton. Phytoplankton include algae and cyanobacteria that photosynthesize, while zooplankton feed on other plankton. Both groups are further divided based on size into bacterio, nano, micro, macro, and meg plankton. The document provides examples for different classifications.

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.

9. 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.

10. • 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.

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

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

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

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

16. 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.

17. Euphasia superba (Antartic krill)

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