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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)
Interrelationships Among the Subprojects
Land Use
Zooplankton
Community
Structure & Dynamics
Theme 3
Distributional &
Physiological
Effects of water
quality on Fish
Theme 4
Climate Variability
HABs Occurrence
& Dynamics
Theme 2
Effects of water
quality on
HamatodiniumBlue crab
relationships
Theme 5
Weather
What are Plankton?
What are Zooplankton?
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 & animallike protists
– Bacterioplankton (bacteria)
Phytoplankton
Zooplankton
Animal Phyla & Animal-like Protists
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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)
Classification of Plankton by Size
• Net Plankton:
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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)
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
Planktonic as a larva (live in the water column)
Benthic as adult (live on the bottom)
Planktonic as a larva (live in the water column)
http://www.bluecrab.info/lifecycle.html
Benthic as adult (live on the bottom)
Life cycle of a squid, a meroplankton
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)
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
Copepods
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
Cladocerans, Ostracods, Mysids,
Amphipods, Euphausids
*Most are small filter feeders straining algae out of water
*Some (e.g.) mysids are also active predators
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
Radiolarians
Radiolarians contd.
Foraminifers
Other Zooplankton contd.
 Other important grazers include: ciliates (Phylum
Ciliophora) and small flagellates (Phylum
Sarcomastigophora)
 Are nanoplankton
 Are major grazers of the nanophytoplankton
Examples of some plankton members of the
Kingdom Protista
(a) Foraminiferan (b) Radiolarian (c) Ciliate
Flagellate (e) Flagellate
(d)
Holoplanktonic Members of the Phylum:
Cnidaria
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Includes:
(a) Jellyfishes of the classes Hydrozoa and
Scyphozoa and
(b) Complex hydrozoan colonies known as
siphonophores
*Scyphozoan jellyfishes are among the largest
planktonic organisms and may occasionally be
found in large numbers
A Hydrozoan Jellyfish
(Crassota alba)
The large Scyphozoan Jellyfish (Pelagia colorata)
with juvenile cancer crabs
Jellyfish (scyphozoan) & Siphonophore
(Colonial hydrozoan; Physalia)
Ctenophore
Tomopteris
(A holopelagic polychaete)
Nekton active swimmers
Benthos bottom dwellers
• Epifauna
• Infauna
• Nektobenthos
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
Meroplankton. Examples from several phyla
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
Microbial Loop & Relationship to the “Classical”
Plankton Food Web
Guinea Worm (Dracunculus medinensis) Transmission in the Tropics
http://upload.wikimedia.org/wikipedia/commons/2/27/Drac_life_cycle.gif
Transmission of Pathogenic Bacteria
 Harbor various types of pathogenic bacteria
 Vibrio species
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Vibrio cholerae
Vibrio vulnificus
Vibrio parahaemolyticus
Vibrio alginolyticus
Importance in Aquaculture
Main Species of Rotifer Used
for Rearing Larval Fish
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Brachionus plicatilis (Marine)
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B. rotundiformis (Marine)
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B. calyciflorus (freshwater)
Rotifers
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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=...
Problem in the Use of B.
plicatilis to Rear Larval Fish
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Are too Big to be Consumed by Larvae of
Some Marine Fish (e.g. Red Snapper).
– Large Strain (L)
– Small Strain (S)
– Super Small Strain (SS)
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200 - 360 micron
150 - 220 micron
94 - 163 micron
Isolation and Culture of a Small Marine
Rotifer, Colurella dicentra
(Chigbu & Suchar 2006)
Copepods
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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:
www.woodbridge.tased.edu.au
/ mdc/Species%20Reg...
Harpacticoid
Cyclopoid
Calanoid
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
Some environmental factors that regulate the
abundance of zooplankton
Planktivorous fish,
Mysids
&
Ctenophores
Mesozooplankton
Community
Structure &
Dynamics
Land Use
Phytoplankton
including HABs
Occurrence
& Dynamics
Microzooplankton
Community
Structure &
Dynamics
Climate Variability
Weather
Maryland Coastal Lagoons
Examples of Negative Effects of HABs
(A. anophagefferens) on zooplankton
 Negative effect on growth of hard clam larvae
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(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.
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
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
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.
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)
Methods of Preserving Zooplankton
 Formalin (10% buffered)
 70% Ethanol
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
Thank You!