Zooplankton

Textbook:

Biological Oceanography: An Introduction, C.M. Lalli, T.R. Parsons, Elsevier, Open University Oxford, 2000. Chapter 4

Basic ecological divisions of the sea

(Lalli & Parsons 1995)

Marine communities

Plankton: passively drifting, despite some smale scale movementsVirioplankton Bacterioplankton (Bacteria + Archaea)MycoplanktonPhytoplanktonProtozooplankton / Metazooplankton

Nekton: actively moving against currents

Benthos: living in the benthal.Phytobenthos, Zoobenthos, Bacteriobenthos (Bacteria,Archaea)

Holoplankton: entire life cycle as plankton

Meroplankton: only partially planktonic life cycle

Size classes of the plankton

(Sieburth 1978)

A marine pelagic food web

(Garrison 1999)

Classic food chain, microbial loop and viral loop

Phytoplankton Zooplankton Fish„herbivorous“ carnivorous

viruses

protozoans

dissolved organicmaterial

sinking Phytoplankton,

marine snow sinkingfecal pellets

heterotrophicbacteria

Microbial Loop

Abundances of groups of planktonic organisms

Copepods <20 L-1 <102 L-1

Cladocerans <60 L-1 <102 L-1

Rotifers <500 L-1 <103 L-1

Ciliates <100 mL-1 <105 L-1

Flagellates <1000 mL-1 <106 L-1

Algae <1000 mL-1 <106 L-1

Bacteria <1-10 Mio mL-1 <1010 L-1

Zooplankton sampling devices

Niskin bottles mounted on a CTD (conductivity, temperature, depth)

Zooplankton sampling devices

Common hand net Big net

Zooplankton sampling devices

Bongo net Multi-net

Major taxonomic groups of the zooplankton 1

Realm Protista

Phylum Flagellata

often mixotrophic(Euglenophyta, Dinophyta, Cryptophyta, Chromophyta)

Phylum Rhizopoda

Class Amoebina, naked Amoebae, mainly benthic, few planktonic forms.“ Testacea, mainly benthic, wenige few planktonic forms. “ Foraminifera, strictly marine, calcium carbonate frustule, mainly benthic but

several planktonic forms. “ Heliozoa, mainly limnetic“ Radiolaria, strictly marine, silicate frustule, mainly planktonic.

Phylum Ciliata

Besides flagellates most important group of the marine protozooplankton

Protozooplankton (Foraminifera)

Protozooplankton (Foraminifera)

Protozooplankton (Foraminifera)

Protozooplankton (radiolariens)

Protozooplankton (ciliates)Strombidium capitatum

Vorticella sp.

Major taxonomic groups of the zooplankton 2

Realm Animalia

Phylum Cnidaria

Class Hydrozoa, manly marine, planktonic stage (medusa, gellyfish), benthic stage (polyp), order Siphonophora strictly planktonic.

“ Scyphozoa, strictly marine.

Phylum Ctenophora, strictly marine.

Phylum Nemathelminthes

Class Rotatoria (rotifers), important limnetic group, very few marine forms, reproduction by parthenogenesis.

Phylum Chaetognata (arrow worm), strictly marine. predator

Phylum Mollusca

Class Gastropoda (snails), few holoplanktonic forms (Pteropoda). “ Cephalopoda (octopus), strictly marine, smallest forms are transient to the nekton.

Major taxonomic groups of the zooplankton 3

Realm Animalia ff

Phylum Annelida

Class Polychaeta, few marine planktonic forms.

Stamm Arthropoda

Class Crustacea Subclass Phyllopoda, mainly limnetic, important group of the limnetic

zooplankton, reproduction by parthenogenesis. “ Copepoda, important group of the zooplankton. “ Decapoda, important group of the marine zooplankton.

Euphausiacea (Krill), important order of the decapods.

Phylum ChordataSub-phylum Tunicata

Class Appendicularia, important group of the marine zooplankton. “ Thaliacea, important group of the marine zooplankton.

Major taxonomic groups of the zooplankton 4

Meroplanktonic Larvae of:

Benthic animals

(Trochophora-larvae of polychaetes, Nemertini, Sipunculidae, bryozoans) Veliger-larvae, of Bivalvia (shells), Gastropods (snails), Pluteus-arvae, of seeurchins, Bipinnaria-larvae, of starfish, Nauplii, Zoea, Megalopa of benthic crustaceans.

Insekts (Chaoborus)

Fish

Lalli & Parsons 1995

Meroplankton

Metazooplankton (hydrozoans)Polyorchis sp.

Eutonina sp.

Mitrocoma sp.

Cnidaria (syphonophores)

Lalli & Parsons 1995

Metazooplankton (hydrozoans)

Physophora sp.

Syphonophora

Ctenophora

Pleurobrachia sp.

Bolinopsis vitrea.

Hormiphora sp.

Chaetognath (arrow worm) (Sagitta elegans)

Lalli & Parsons 1995

Chaetognath

SyphonophoraStaatsqualle

Pteropoda

Corolla spectabilis

Polychaeta

Hirche 1995Lalli & Parsons 1995

Crustacea

Copepods

Hirche 1995

Crustacea (copepods)

Paraeuchaeta norvegica

Paraeuchaeta elongata

Copepoda

Eurytemora affinis

CyclopoideaPaired egg cluster

Calanoidea1 egg cluster

Pseudodiaptomus inopinus

Krill (Decapoda, Euphausiaceae)

Euphausia superba

Food web in the Southern Ocean

Lalli & Parsons 1995

Tunicata, Appendicularia

Oikopleura sp.

Oikopleura sp.

Tunicata, Appendicularia

Tunicata, Thaliaceae (salps)

Cyclosalpa affinis

Tunicata, Thaliaceae (salps)

Alternation of generationsIasis zonaria

Tunicata, Thaliaceae

Cyclosalpa bakeri Cyclosalpa affinis

Tunicata, Thaliaceae

Cyclosalpa sp.

Tunicata, pyrosomes

Pyrosoma tuberculata.

Diel vertical migration of the zooplankton

Lalli & Parsons 1995

Diel vertical migration of the zooplankton

Lalli & Parsons 1995

Diel vertical migration of the zooplankton

Lalli & Parsons 1995

Saisonal vertical migration of the zooplankton

Lalli & Parsons 1995

Trophic levels in food webs– unproductive regions

Lalli & Parsons 1995

6 levels Unproductive regionsPrimary producers: nano- and picophytoplankton.Many transfer steps with low size increments.

Trophic levels in food webs – continental shelf

Lalli & Parsons 1995

4 levels Continental shelf,Primary producers: microphytoplankton.Transfer steps with medium size increments.

Trophic levels in food webs – upwelling regions

Lalli & Parsons 1995

3 levels Upwelling regions, nutrient richPrimary producers: macrophytoplankton.Few transfer steps with large size increments.