1. Dynamics of Zooplankton Community in Maryland Coastal Bays and Their Driving Mechanisms CREST Teacher Development Workshop July 17, Paulinus Chigbu, Ph.D. University of Maryland Eastern Shore

2. Goal 1: Study, understand, model & predict the impacts of land use & climate variability
Subproject 1: Water quality dynamics in relation to land use and climate variability (Project Leaders: Eric May & Ali Ishaque)
Subproject 2: Understand the dynamics of phytoplankton and macroalgae species including HABs in MCBs (Project Leaders: Madhumi Mitra & Chunlei Fan)
Subproject 3: Dynamics of zooplankton community structure and the driving mechanisms (Project Leaders: Paulinus Chigbu & Kam Tang)
Subproject 4: Physiological effects of hypoxia and environmental contaminants on Atlantic croaker (Project Leader: Andrea Johnson)
Subproject 5: Effects of environmental factors on blue crab and its relation to infection by Hematodinium sp. (Project Leaders: Joseph Pitula & Sook Chung)

3. Interrelationships Among the Subprojects
Zooplankton Community
Structure & Dynamics
Theme 3
HABs Occurrence
& Dynamics
Theme 2
Distributional &
Physiological
Effects of water quality on Fish
Theme 4
Effects of water quality on Hamatodinium-
Blue crab relationships
Theme 5
Water
Quality
Dynamics
Theme 1
Climate Variability
Weather
Land Use

4. What are Plankton? What are Zooplankton?

5. Plankton Two sub-divisions of plankton:
Aquatic organisms that have limited powers of locomotion & therefore can not swim independent of water movement
Two sub-divisions of plankton:
Phytoplankton: Free-floating organisms capable of photosynthesis
Zooplankton: Free-floating animals & animal-like protists
Bacterioplankton (bacteria)

6. Phytoplankton

7. Zooplankton

8. Animal Phyla & Animal-like Protists
Protozoan Groups
Sponges: Phylum Porifera
Radiate Animals: Phylum Cnidaria & Phylum Ctenophora
Acoelomate Bilateral Animals: e.g. Flatworms (Phylum Platyhelminthes)
Pseudocoelomate Animals (e.g. Phylum Rotifera)
Molluscs (Phylum Mollusca)
Segmented Worms (Phylum Annelida)
Arthropods (Phylum Arthropoda)
Echinoderms (Phylum Echinodermata)
Chordates (Phylum Chordata)

9. Classification of Plankton by Size
Net Plankton:
Megaplankton (> 20 cm)
Macroplankton (2 – 20 cm)
Mesoplankton (0.2 – 20 mm)
Microplankton (20 – 200 micron)
Nanoplankton: (2 – 20 micron)
Picoplankton: (0.2 – 2 micron)-> bacteria & cyanobacteria
Femtoplankton: (0.02 – 0.2 micron)

10. Classification of Zooplankton based on Life History Characteristics
Holoplankton: Spend their entire lives in the water column as plankton
Meroplankton: Spend part of their lives in the water column

11. Planktonic as a larva (live in the water column)
Planktonic as a larva (live in the water column)
Benthic as adult (live on the bottom)
Benthic as adult (live on the bottom)

12. Life cycle of a squid, a meroplankton

13. Diversity of Zooplankton
Zooplankton consist of a host of larval & adult forms that represent most of the animal & many of the protistan phyla.
In the marine environment, the dominant net zooplankton are the copepods (subclass: Copepoda; subphylum: Crustacea; Phylum: Arthropoda)

14. Copepods May be free-living, planktonic, benthic or parasitic
Free-living planktonic forms swim weakly, using their jointed thoracic limbs & have a characteristic jerky movement
Use their large antennae to slow their rate of sinking

15. Copepods

16. Reproduction in Copepods
Sexes are separate
Sperm packaged in spermatophores is transferred to the female
Eggs are fertilized & enclosed in a sac attached to the female’s body
Eggs hatch into nauplius larvae which pass through many naupliar stages, copepodid stages and finally adult stage

17. Cladocerans, Ostracods, Mysids, Amphipods, Euphausids
*Most are small filter feeders straining algae out of water
*Some (e.g.) mysids are also active predators

18. Other Zooplankton Kingdom: Protista Phylum: Sarcomastigophora
Order: Foraminiferida (forams)
Order: Radiolaria
*Important grazers in the marine environments
*Net plankton, Holoplankton
*Radiolarians & foraminiferans are single-celled organisms that produce skeletons of CaCO3 and SiO2 (glass), respectively
*Thick layers of their skeletal remains occur on the ocean floor as foraminiferan and radiolarian ooze

19. Radiolarians

20. Radiolarians contd.

21. Foraminifers

22. Other Zooplankton contd.
Other important grazers include: ciliates (Phylum Ciliophora) and small flagellates (Phylum Sarcomastigophora)
Are nanoplankton
Are major grazers of the nanophytoplankton

23. Examples of some plankton members of the Kingdom Protista (a) Foraminiferan (b) Radiolarian (c) Ciliate (d) Flagellate (e) Flagellate

24. Holoplanktonic Members of the Phylum: Cnidaria
Includes:
Jellyfishes of the classes Hydrozoa and Scyphozoa and
Complex hydrozoan colonies known as siphonophores
*Scyphozoan jellyfishes are among the largest planktonic organisms and may occasionally be found in large numbers

25. A Hydrozoan Jellyfish (Crassota alba)

26. The large Scyphozoan Jellyfish (Pelagia colorata) with juvenile cancer crabs

27. Jellyfish (scyphozoan) & Siphonophore (Colonial hydrozoan; Physalia)

28. Ctenophore

29. Tomopteris (A holopelagic polychaete)

30. Nekton active swimmers

31. Benthos bottom dwellers
Epifauna
Infauna
Nektobenthos

32. Meroplankton
Larvae of meroplankton are derieved from virtually all animal phyla and from all different marine habitats
Larvae of Decapod crustaceans, Bryozoa, Phoronida, Echinodermata, Porifera, Nemertea, Mollusca and Annelida

33. Meroplankton. Examples from several phyla

34. Role of Zooplankton in Aquatic Ecosystems and Significance to Humans
Role in food webs
Role in disease transmission
Transmission of guinea worm in the tropics
Transmission of pathogenic bacteria
Importance in aquaculture

35. Microbial Loop & Relationship to the “Classical” Plankton Food Web

36. Guinea Worm (Dracunculus medinensis) Transmission in the Tropics

37. Transmission of Pathogenic Bacteria
Harbor various types of pathogenic bacteria
Vibrio species
Vibrio cholerae
Vibrio vulnificus
Vibrio parahaemolyticus
Vibrio alginolyticus

38. Importance in Aquaculture

39. Main Species of Rotifer Used for Rearing Larval Fish
Brachionus plicatilis (Marine)
B. rotundiformis (Marine)
B. calyciflorus (freshwater)

40. Rotifers
Commonly used species: Brachionus plicatilis (~239 mm) and B. rotundiformis (~160 mm)
Used in the rearing of over 100 spp. of fish and crustaceans
Fast growing and relatively easy to culture
Still, too big for some marine fish larvae
Pictures: vivo.library.cornell.edu/ servlet/entity?home=...

41. Problem in the Use of B. plicatilis to Rear Larval Fish
Are too Big to be Consumed by Larvae of Some Marine Fish (e.g. Red Snapper).
Large Strain (L) = micron
Small Strain (S) = micron
Super Small Strain (SS) = micron

42. Isolation and Culture of a Small Marine Rotifer, Colurella dicentra
(Chigbu & Suchar 2006)

43. Copepods Common in marine environments
Principal diet of many marine fish larvae in nature
High content in nutrients
Size: 0.5 – 50 mm
Difficult to mass culture (unpredictable yields)
Only few sp. (Tigriopus japonicus) successfully mass cultured
Pictures: mdc/Species%20Reg...
Harpacticoid
Cyclopoid Calanoid

44. Zooplankton of the MCBs
MCBs serve as nurseries for larvae and juveniles of many economically and ecologically important fish species
Zooplankton are important components of the aquatic food webs
Dynamics of zooplankton community in coastal aquatic ecosystems depend on many factors including climate variability, water quality & biotic interactions

45. Some environmental factors that regulate the abundance of zooplankton
Mesozooplankton Community
Structure & Dynamics
Phytoplankton including HABs Occurrence
& Dynamics
Water
Quality
Dynamics
Theme 1
Climate Variability
Weather
Land Use
Planktivorous fish, Mysids
&
Ctenophores
Microzooplankton Community
Structure & Dynamics

46. Maryland Coastal Lagoons

47. Examples of Negative Effects of HABs (A
Examples of Negative Effects of HABs (A. anophagefferens) on zooplankton
Negative effect on growth of hard clam larvae
(Padilla et al. 2006)
Inhibit growth of some ciliates, e.g. Strombidium sp. (Caron et al. 2004, Lonsdale et al. 1996)
Delay in copepod nauplii development; deterrence to grazing by copepod nauplii (Smith et al. 2008)
Poor survival of copepodites of Acartia hudsonica and nauplii of Coullana canadensis fed unialgal diet (Lonsdale et al. 1996).
Toxicity to copepod nauplii (Buskey & Hyatt 1995, Buskey et al. 2003) --- Aureoumbra lagunensis.
Decrease in copepod egg viability (Felipe et al. 2006) ---- Karlodinium sp.

48. Need for Zooplankton Studies in MCBs
As changes occur in the trophic state of the Coastal Bays, it is important to study and understand the impacts of such changes on zooplankton community.
Information on the dynamics of zooplankton in the MCBs is very limited
Monitoring of the mesozooplankton community

49. Objectives
Determine the assemblage/community structure of micro- and mesozooplankton in relation to water quality
Examine mesozooplankton mortality in situ, using a novel staining technique (Elliott & Tang 2009), under HAB and non-HAB conditions
Examine mesozooplankton feeding, growth rates and reproduction under HAB and non-HAB conditions

50. Objectives contd.
Quantify the size distribution, density and biomass of ctenophores Mnemiopsis leidyi relative to environmental factors
Examine using field studies and laboratory experiments whether ctenophores are having any significant effects on zooplankton community structure.

51. Methods of Collecting Zooplankton Samples
Plankton Nets (Horizontal vs Vertical/Oblique Tows)
Bongo Nets (Horizontal vs Vertical/Oblique Tows)
Pumps
Traps (e.g. Schindler-Patalas Trap)

52. Methods of Preserving Zooplankton
Formalin (10% buffered)
70% Ethanol

53. Estimating Zooplankton Densities in Water
Flow meter
Record flow meter counts at the beginning & end of the tow, and find the difference
Tow for about 3 minutes
Estimate distance (m) covered during the tow
Distance (m) = Diff. in counts X Rotor Constant
999999
Rotor Constant for flow meter (2030R) = 26,873
Vol. (m3) = Distance (m) X area of the mouth opening of the net

54. Thank You!