Zooplankton are small aquatic animals that drift or float in water and rely on currents for movement. Without environmental controls, the entire world could be covered by a 3-foot thick layer of zooplankton in just 130 days. Zooplankton are classified based on size from femtoplankton to megaplankton. They also have holoplankton that remain plankton their whole life and meroplankton that are partially planktonic. Common phyla include protozoa, cnidaria, chaetognatha, annelida, mollusca, arthropoda, and chordata.

1. By
G.Kantharajan
AEM-PA6-01
KANTHARAJAN G
AEM-PA6-01
ICAR-CIFE

2. ‘’Floating or weakly swimming
animals that rely on water currents
to move any great distance’’
Greek words:
"zoon -animal", "planktos -drifter"
Zooplankton

3. IS it???
Without environmental factors which keep reproduction of
some species of zooplankton (such as Filinia) under control,
entire world would be covered with 3-feet-thick layer of
zooplankton in 130 days.
(http://www.softschools.com/facts/organisms/zooplankton)

4. 1 st size classification of zooplankton was given by (schutt 1892)
CATEGORY SIZE RANGE DESCRIPTION
Femtoplankton 0.02-0.20 um marine viruses
Picoplankton 0.2-2 um
small eukaryotic protists; bacteria;
Chrysophyta
Nano plankton 2-20 um
Heterotrophic nanoflagellates
feeding on bacteria
Microplankton 20-200 um Protozoans like ciliates
Mesoplankton 0.2-20 mm Metazoans (Copepod, Medusa etc..)
Macroplankton 20-200 mm
Members of hydromedusae, mysids,
Siphonophores, scyphomedusae,
ctenophores, eel larvae
Megaplankton
> 200 mm (almost 8
inches)
Metazoans (Jelly fish)
Classification based on size

5. Based on developmental stages
Meroplankton only partially planktonic life cycle
(eg) crab zoea, snail veliger, Bipinnaria of
starfish etc…
Holoplankton remain plankton for their entire
life cycle (eg) pteropods , chaetognaths,
siphonophores, and copepods.

6. Phylum Sub groups Examples
Protozoa
Dinoflagellates Noctiluca
Foraminifera Globigerina
Radiolaria Radiolaria
Ciliates Favella
Cnidaria
Medusae Aruelia
Siphanophores Pyrosoma
Ctenophora Pleurobrachia
Chaetognatha Sagitta
Annelida Tomopteris
Mollusca
Limacina
Clione
Arthropoda
Cladocera Penilia avirostris
Copepods Calanus sp.
Euphausids Euphausia superpa
Chordata
Appendicularia Oikopleura dioica
Salps Salpa
Taxonomic groups of some marine holo zooplankton

7. Nanoplanktonic Flagellates
Characterized by either a long tail used for
swimming (flagellates) OR
by hair-like structures called cilia (Ciliates
Cnidaria
contains the colonial siphonophores and
the scyphozoans—also known as the true
jellyfish
Rotifers
 Most are non-motile, about 100 species are
holoplanktonic.
 Rotifers eat bacteria, detritus, other rotifers,
algae or protozoa.
 Rotifers are highly efficient reproducers

8. Chaetognatha
 Most macrozooplankton are copepods found in
marine and freshwater ecosystems.
 Swim using an antenna and frontal structures
• Arrowwormsare mostly holoplanktonicand are abundant worldwide.
• These transparent wormsare approximately3 cm long and have fins on
the sidesof their bodies.
Marine Gastropods
Copepods
larvae of benthic molluscs usually found in coastal
waters including heteropods or pteropods.

9. Polychaeta
class of annelid worms, generally marine.
Each body segment has a pair of fleshy
protrusions called parapodia that bear many
bristles, called chaetae, which are made of chitin
Cladocerans
planktonic crustaceans found in
coastal waters; swim using second
antenna
Insect Larvae
larvae of the midge Chaoborus is the only
widely known insect larvae classified as
plankton.

10. Tunicates
 classes Appendicularia and Thaliasia. Both
are filter feeders
 Appendicularia consumes small food
particles using a mucous filter.
 Other types of tunicates are benthic and are
only planktonic during their larval stages
 Classified under Euphausids
 found all over the world.
 can be 3 cm large and are an
important source of food for many
types of whales.
 Serves as an indicator organism for
the presence of baleen whales in the
polar waters.
krill

12. All the organisms living or inhabiting in the bottom regions of the aquatic environment
are termed benthos.
Macro benthos are organisms that are
larger than 1 mm
E.g. oysters, starfish, lobsters, sea
urchins,
Meio benthos are between 0.1 and 1 mm
E.g. ciliates, annelids
Micro benthos are very tiny organisms.
They are smaller than 0.1 mm E.g.
bacteria and ciliates
BENTHOS
CLASSIFICATION BASED ON SIZE…..

13. Endobenthic organisms are the
meiofaunal sized organisms which move
within the sediment by displacing particles
eg. Sand dollar
Mesobenthic organisms are the
meiofaunal organisms living and moving
within the interstitial spaces of the grains.
eg,. Sea cucumber
Epibenthic organisms are those that living
at the sediment-water interface
Eg. Rock Cod
CLASSIFICATION BASED ON LOCATION…..

14. Based on the mode of life
Epifaunal organisms : animals which
live on the substratum.
Infaunal organisms : are those that
animals live into the substratum.
Burrowers : Organisms that penetrate or
burrow into the unconsolidated bottom
sediments are called burrowers.
Borers : organisms those that penetrate
or bore the hard rock or substrate
materials are called borers.
Based on mobility
1. Sessile benthos
- do not have any mobility, attached
or fixed with the substratum - rely on
currents or other mechanisms to
bring food to them.
E.g. enthic algae, sea grasses ,corals
2. Vagrant benthos
- are those that have locomotory
powers and either they can move
rapidly or slowly.
E.g. Only animals are included under
this category.

15. Benthic plants

16. zoo benthos
Arthropods : The crabs and lobsters are the largest and fastest of the vagrant benthos. In
addition, they have some swimming ability, using either their tails and/or specially adapted legs.
Echinoderms : They have numerous appendages in the form of sucker feet or spines that are
used for locomotion.
The sea urchins live on hard substrates where they feed on debris.
Sand dollars have the poorest mobility but they can move slowly by the whisker-like feet that
surround their body.
Sedentary or Vagrant epifauna: They may live on rigid substrate, firm sand or
soft mud. While some move very slowly, others move very quickly.
Foraminifera: less than a millimetre in dia
with different shaped tests and most of
which are multi-chambered
Shelled invertebrates

17. Sessile epifauna
Many organisms are attached to the substrate throughout their
maturity and have no mobility at all. These include,
Brachiopods: attach with a stem like foot that extends from
near the hinge line that holds the shells together.
Mussels are about the same size and they attach themselves to
a hard surface with strong thread like structures, called byssus
threads which develop at the hinge line

18. INFAUNAL ORGANISMS
 includes various meiofaunal and macro fauna such as snails,
clams, worms, sea urchins, and crustaceans.
 Some groups are entirely infaunal, tusk shells
two different models of life
1. Some graze or plow through the sediment (sediment
destabilizers)
2. others construct extensive burrow complexes that they
occupy and in which they move about (sediment
stabilizers)

19. Nekton vs Plankton vs Benthos
o Nekton live throughout the water column whereas plankton live
closer to the water surface.
o Unlike nekton and planktons, benthos linked to the ocean floor.
o Unlike the planktons and benthos, nekton can propel themselves
either by swimming or other means.
o Many planktons are microscopic or small animals, when
compared to the other two types.
o Some benthos are free living, while others live attached to the
seabed. However, all the nekton are free living animals.

20. Reference
 http://marinebio.org/oceans/zooplankton/
 Lalli, C. and Parsons, T.R., 1997. Biological
oceanography: an introduction. Butterworth-Heinemann.
 http://www.elearnfish.net
 Schütt, F., 1892. aus: Biological Oceanography, An Early
History, 1870-1960.

21. MAY BE THROWN BY US…
A VIEW OF littersin VERSOVA BEACH DURING neap tide
THANKU