1. Zooplankton
Dr. Jason Turner
MARE 444

2. Zooplankton Protozoans (Kingdom Protista)
Size varies from microns (μm) to meters (m)

3. They’re Heterotrophic
Herbivores –
Carnivores –
Detritivores –
Omnivores –
Planktivores -

4. Zooplankton Stenohaline - (limited to a narrow range of salinity)
found near mouth of estuary
Euryhaline - (more tolerant of salinity variation)
penetrating further up estuary
Estuarine - species confined to estuary
Freshwater - species normally found in freshwater

5. Planktonic Life Styles
Holoplankton –
Meroplankton -

6. Collecting Plankton

7. Collecting Plankton Horizontal tow Vertical tow Oblique tow Mesh size
Gear avoidance
Volume of water sampled
Fragile organisms

8. Flow Cam Images

9. Flow Cam Images

10. Protozoans
Single celled
Small (often overlooked)

11. Protozoans Dinoflagellates Zooflagellates Foraminiferans Radiolarians
Ciliates

12. Dinoflagellates Peduncle - a cytoplasmic extension used in phagotrophy
Half of dinos are heterotrophic

13. Dinoflagellates

14. Zooflagellates Strictly heterotrophic (microbial loop?)
Typically 2-5 m in length
High reproductive rates
20-80% of nanoplankton = food source

15. Zooflagellates

16. Foraminiferans Phylum Foraminifera
Amoeboid critters with a shell (test) made of calcium carbonate
Test can be used to ID species and reconstruct past environments
Rhizopods, feed on bacteria, phytos, zooplankton
Chalk, White Cliffs of Dover, ooze

17. Foraminiferans

18. Radiolarians Phylum Polycystina Amoeboid critters with silica shells
Shells are typically spherical with radiating spines
Pseudopodia
Common in cold waters
Some are deep-sea species
Siliceous ooze

19. Oozes

20. Radiolarians

21. Ciliates Phylum Ciliophora
Hair-like cilia used in locomotion and feeding
Specialized, advanced cells

22. Ciliates

23. Microbial Loop

24. Holoplanktonic metazoans
Most primitive are cnidarians
Jellyfish (medusae)
some are holoplanktonic, others are meroplanktonic
all are carnivorous
Siphonophores
colonial forms; Physalia
Box jellies: Chironex

25. Medusae

26. Siphonophores & Box jellies

27. Ctenophores Phylum Ctenophora
Look like jellyfish, but have 8 rows of fused cilia
Do not sting

28. Ctenophores

29. Chaetognaths Phylum Chaetognatha Arrow worms Carnivorous
Rapid swimmers – long trunk muscles

30. Chaetognaths

31. Polychaetes Phylum Annelida, Class Polychaeta
Tomopteris - a planktonic worm
40 species, all predators

32. Tomopteris

33. Holoplanktonic mollusks
swim by undulating a single fin
some have reduced, or absent shell
visual predators
warm, oceanic water

34. Heteropods

35. Pteropods Sink to bottom produce pteropod ooze Thecosomes
most have a shell
suspension feeders
Gymnosomes (naked pteropods)

36. Pteropods

37. Crustaceans Phylum Arthropoda Class Crustacea
Very common planktonic animals
Copepods are most common

38. Copepods Order Calanoida 1850 species ubiquitous
12 different stages of development from egg to adult - easy to study

39. A calanoid copepod

40. Copepod Life Cycle

41. Cyclopod copepods
Order Cyclopodia
250 planktonic species

42. A cyclopod copepod

43. Harpacticoid copepods
Coastal, or associated with the benthos
20 species are holoplanktonic
No distinct divisions between body regions
May be seasonally or locally abundant, but ecological importance is not great

44. An harpacticoid copepod

45. Euphausiids
Shrimp-like animals
86 species
Euphausia superba -

46. Euphausiid

47. Amphipods Laterally compressed body
Some are parasitic, others are carnivorous, etc.

48. Amphipods

49. Ostracods Unique, hinged bivalved exoskeleton Scavengers?
Usually small, deep-sea individuals can get big
Little work has been done on this group

50. Ostracods

51. Cladocera Mainly a freshwater group, 8 marine species
Daphnia - the water flea
Coastal and brackish water
Primitive group - capable of producing cloned offspring (parthogenesis)

52. Cladocera

53. Mysids
Spend most of the time on sea floor, rise in the water column to feed at night
Estuarine, nearshore waters
Harvested in Asia

54. Mysids

55. Decapods Omnivores or carnivores Active at night, vertical migrations
Important prey for tuna, dolphins, and whales

56. Shrimp

57. Chordates Phylum Chordata Appendicularians 70 marine species
also called larvaceans
make a mucus house
marine snow
filter feeders

58. Larvaceans

59. Salps
Asexual budding
Hermaphorditic
r-selected organism

60. Salps