Dynamics of Zooplankton Community in Maryland Coastal Bays and Their Driving Mechanisms CREST Teacher Development Workshop July 17, 2012 Paulinus Chigbu, Ph.D. University of Maryland Eastern Shore

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 & 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

What are Plankton? What are Zooplankton?

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)

Phytoplankton

Zooplankton

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)

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

Planktonic as a larva (live in the water column) http://www.bluecrab.info/lifecycle.html Planktonic as a larva (live in the water column) Benthic as adult (live on the bottom) 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 (d) Flagellate (e) Flagellate

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

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 Vibrio cholerae Vibrio vulnificus Vibrio parahaemolyticus Vibrio alginolyticus

Importance in Aquaculture

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

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=...

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) = 200 - 360 micron Small Strain (S) = 150 - 220 micron Super Small Strain (SS) = 94 - 163 micron

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

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: 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 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

Maryland Coastal Lagoons

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.

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!