Goal 1: 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

Zooplankton Community

Structure & DynamicsTheme 3

HABs Occurrence & Dynamics

Theme 2

Distributional & Physiological Effects of water quality on Fish

Theme 4

Effects of water quality on

Hamatodinium- Blue crab

relationshipsTheme 5

Climate Variability Weather

Land Use

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 & animal-like protists

– Bacterioplankton (bacteria)

Phytoplankton

Zooplankton

Animal Phyla & Animal-like ProtistsProtozoan GroupsSponges: Phylum PoriferaRadiate Animals: Phylum Cnidaria & Phylum

CtenophoraAcoelomate 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:– 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

http://www.bluecrab.info/lifecycle.html

Benthic as adult (live on the bottom) Benthic as adult (live on the bottom)

Planktonic as a larva (live in the water column) Planktonic as a larva (live in the water column)

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)

CopepodsMay 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

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

*Most are small filter feeders straining algae out of water*Some (e.g.) mysids are also active predators

Other ZooplanktonKingdom: Protista Phylum: SarcomastigophoraOrder: 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 (d) Flagellate (e) Flagellate

Holoplanktonic Members of the Phylum: Cnidaria

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

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

Ctenophore

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

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

Transmission of Pathogenic Bacteria

Harbor various types of pathogenic bacteria

Vibrio species Vibrio cholerae Vibrio vulnificus Vibrio parahaemolyticus Vibrio alginolyticus

Importance in Aquaculture

Brachionus plicatilis (Marine)

B. rotundiformis (Marine)

B. calyciflorus (freshwater)

Main Species of Rotifer Used Main Species of Rotifer Used for Rearing Larval Fishfor Rearing Larval Fish

RotifersRotifers

Fast growing and relatively easy to culture Still, too big for some marine fish larvae

Pictures: vivo.library.cornell.edu/ servlet/entity?home=...

Commonly used species: Brachionus plicatilis (~239 m) and B. rotundiformis (~160 m)

Used in the rearing of over 100 spp. of fish and crustaceans

Are too Big to be Consumed by Larvae of Some Marine Fish (e.g. Red Snapper).

– Large Strain (L) = 200 - 360 micron

– Small Strain (S) = 150 - 220 micron

– Super Small Strain (SS) = 94 - 163 micron

Problem in the Use of Problem in the Use of B. B. plicatilisplicatilis to Rear Larval Fish to Rear Larval Fish

Isolation and Culture of a Small Marine Isolation and Culture of a Small Marine Rotifer, Rotifer, ColurellaColurella dicentra dicentra

(Chigbu & Suchar 2006)(Chigbu & Suchar 2006)

CopepodsCopepods

Harpacticoid

Cyclopoid Calanoid

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...

Zooplankton of the MCBsMCBs 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

Mesozooplankton Community

Structure & Dynamics

Phytoplankton including HABs

Occurrence & Dynamics

Climate Variability Weather

Land UsePlanktivorous fish, Mysids

& Ctenophores

Microzooplankton

Community Structure & Dynamics

Maryland Coastal Lagoons

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.

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 WaterFlow meterRecord flow meter counts at the beginning & end

of the tow, and find the differenceTow for about 3 minutesEstimate distance (m) covered during the towDistance (m) = Diff. in counts X Rotor

Constant999999

Rotor Constant for flow meter (2030R) = 26,873

Vol. (m3) = Distance (m) X area of the mouth opening of the net

Thank You!