goal 1: goal 1: study, understand, model & predict the impacts of land use & climate...
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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!