Zooplankton Session i

7/22/2019 Zooplankton Session i

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Zooplankton

htt : www.microsco -uk.or .uk


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m

Objectives

Be able to define zooplankton

Be familiar with the major groups of

zooplankton and their characteristics Explain the benefits of zooplankton

Explain how certain zooplankton can

gauge reproductive success


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Zooplankton

Zooplankton are the animal-likemembers of the plankton

Permanent and temporary planktonicforms

Most groups are multicellular and

categorized by mouth parts and/orappendages

Most groups feed as heterotrophic

consumers


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Planktos: drifts in greek

Their distribution depends on currentsand gyres

Certain zooplankton can swim well, butdistribution controlled by currentpatterns

Zooplankton: all heterotrophic planktonexcept bacteria and viruses; size range from 2

m (heterotrophic flagellates, protists) up toseveral meters (jellyfish)


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Major Groups ofZooplankton

Protozoa Ciliates, Amoebae

Rotifera Copepods

Gelatinous Zooplankton

Invertebrate and Vertebrate Larvae


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Protozoa

Single cell organisms

Primarily feed on

bacteria andphytoplankton

Capable ofreproducing rapidlydue to small size

Most species capableof forming cysts

Microzooflagellates,


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Ciliates and Amoebae


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Rotifera

Typically referred toas Rotifers

sloppy feeders onphytoplankton andother zooplankton

recycle nutrient viafeeding and fecalpellets

parthenogenic eggs


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Rotifers


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Copepods

Sloppy feeder onphytoplankton and

other zooplankton Major source of

food for larval fish

Recycles nutrientsvia feeding andfecal pellets


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Copepods


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Gelatinous Zooplankton

Commonly referredto as jellyfish

Most have stingingcells calledcnidocytes butsome are filter

feeders May be permanent

of temporary

members of thelankton


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Ctenophores

Cteno means comb:sometimes calledcomb jellies

Gelatinous filterfeeding organisms-no stinging cells

May bebioluminescent

Common in the Bayin the early Spring


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Comb Jellies


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Cnidarians Stinging cells

Chrysaoraquinequecirrha

Stinging and feedingtentacles

Male and female

forms jelly is the sexual

stage of the life cycleand is called the

medusa stage


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Other CnidariansHydromedusa, Portugese Man-o-war


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Larvae of Invertebrate and

Vertebrate Animals Temporary

members of the

plankton Invertebrates are

animals withoutbackbones: worms,

oysters, crabs Vertebrates are

animals with

backbones: fish


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Nutritional modes in zooplankton

Herbivores: feed primarily on phytoplankton

Carnivores: feed primarily on other

zooplankton (animals)

Detrivores: feed primarily on dead organicmatter (detritus)

Omnivores: feed on mixed diet of plants andanimals and detritus


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Feeding modes in Zooplankton

Filter feeders

Predators catch individual particles


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Filter Feeder

Copepod


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Fil F d


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Filter FeederCtenophore

P d t


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PredatorChaetognathArrow Worm


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Life cycles in Zooplankton

Holoplankton: spend entire life in thewater column (pelagic)

Meroplankton: spend only part of theirlife in the pelagic environment, mostlylarval forms of invertebrates and fish

Ichthyoplankton:fish eggs and fish

larvae


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M l kt


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Meroplankton

Nauplius larvahtt : www.microsco -uk.or .uk


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Barnacles:benthic sessile crustacean

http://science.whoi.edu/labs/pinedalab/


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Meroplankton

htt : www.microsco -uk.or .ukCypris larva


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Cypris larva and metamorphosed juveniles


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Cypris larva and metamorphosed juveniles



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Barnacle population regulation

http://www.larvalbase.org/


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GadidaeGadus morhua

Ichthyoplankton
http://www.larvalbase.org/http://www.larvalbase.org/


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GadidaeGadus morhua

Ichthyoplankton

Gadidae
http://www.larvalbase.org/http://www.larvalbase.org/http://www.larvalbase.org/


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GadidaeGadus morhua

Ichthyoplankton
http://www.larvalbase.org/http://www.larvalbase.org/http://www.larvalbase.org/http://www.larvalbase.org/http://www.larvalbase.org/


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GadidaeAtlantic codGadus morhua

Demersal Adult

l


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Mollusca:clams and snails produce shelled veligerlarvae; ciliated velum serves for locomotion andfood collection

Cirripedia:barnacles produce nauplii, which turnto cypris

Echinodermata:sea urchins, starfish and seacucumber produce pluteus larvae of different

shapes, which turn into brachiolaria larvae(starfish); metamorphosis to adult is very complex

Polychaeta:brittle worms and other wormsproduce trochophora larvae, mostly barrel- shaped

with several bands of cilia

Common Meroplankton


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Decapoda:shrimps and crabs produce zoalarvae; they turn into megalopa larvae in crabsbefore settling to the sea floor

Pisces:fish eggs and larvae referred to asichthyoplankton; fish larvae retain part of the eggyolk in a sack below their body until mouth and

stomach are fully developed

Common Meroplankton


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Meroplankton


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Meroplanktonic Larvae

Planktotrophic Feeding larvae Longer Planktonic Duration Times

High dispersal potential

Lecithotrophic (non-feeding)

Non-feeding larvae Shorter planktonic Duration Times

Low dispersal potential

Molluscs:


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http://www.pbs.org/wgbh/nova/sharks/island/images/veliger.jpeg

MolluscsMeroplankonic Veliger larvaePLANKTOTROPHIC


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Protists: Protozooplankton Dinoflagellates:heterotrophic relatives to the

phototrophic Dinophyceae; naked and thecate forms.Noctiluca miliarisup to 1 mm or bigger,bioluminescence, prey on fish egg & zooplankton

Zooflagellates: heterotrophic nanoflagellates (HNF):taxonomically mixed group of small, naked flagellates,feed on bacteria and small phytoplankton;choanoflagellates: collar around flagella

Foraminifera:relatives of amoeba with calcareousshell, which is composed of a series of chambers;contribute to ooze sediments; 30 m to 1-2 mm,bacteriovores; most abundant 40N 40S


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DinoflagellatesNoctiluca miliaris

C l i l h fl ll t


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http://www.nsf.gov/pubs/1999/nsf98106/98106htm/ht-015.gif

Colonial choanoflagellatesBacteriofages (Ross Sea)


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Foraminifera (calcareous all latitudes)


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Radiolaria:spherical, amoeboid cells with silicacapsule; 50 m to several mm; contribute to silicaooze sediments, feed on bacteria, small phyto- and

zooplankton; cold water and deep-sea

Ciliates:feed on bacteria, phytoplankton, HNF;naked forms more abundant but hard to study

(delicate!); tintinnids: sub-group of ciliates withvase-like external shell made of protein;herbivores

Protists: Protozooplankton


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Figure 3.21b

Radiolarians (siliceous low latitudes)


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http://www.jochemnet.de/fiu/


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https://reader009.{domain}/reader009/html5/0308/5a

Live Radiolarian

H l l k


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Holoplankton

CopepodsPlanktonic crustaceans

I b H l l k


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Cnidaria:primitive group of metazoans; some

holoplanktonic, others have benthis stages;carnivorous (crustaceans, fish); long tentaclescarry nematocysts used to inject venoms intoprey; box jellyfish of Australia kills humans withinminutes

Medusae: single organisms, few mm to severalmeters Siphonophores: colonies of animals with

specialization: feeding polyps, reproductivepolyps, swimming polyps; Physalia physalis(Portuguese man-of-war), common in tropicalwaters, Gulf of Mexico, drifted by the wind andbelong to the pleuston (live on top of watersurface)

Invertebrate Holoplankton


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Cnidaria (medusae)

C id i ( d )


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Cnidaria (medusae)

Cnidaria (siphonophora)


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p p


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Ctenophores:separate phylum, do not belong toCnidaria; transparent organisms, swimm with fusedcilia; no nematocysts; prey on zooplankton, fish

eggs, sometimes small fish; important to fisheriesdue to grazing on fish eggs and competition forfish food

Chaetognaths: arrow worms, carnivorous,


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Ctenophora (comb jellies)



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I t b t H l l kt


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Invertebrate Holoplankton

Mollusca: Heteropods: small group of pelagicrelatives of snails, snail footdeveloped into a single fin; good

eyes, visual predators Pteropods: snail foot developed into

paired wings; suspension feeder produce large mucous nets tocapture prey; carbonate shellsproduce pteropod ooze on sea floor


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Heteropod (Predates on Ctenophores)


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Pteropod http://www.mbari.org/expeditions/


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Protochordate Holoplankton

Appendicularia: group of Chordata, live ingelatinous balloons (house) that are periodicallyabandoned; empty houses provide valuable carbonsource for bacteria and help to form marine snow;filter feeders of nanoplankton

Salps or Tunicates:group of Chordata, mostlywarm water; typically barrel-form, filter feeders;occur in swarms, which can wipe the water clean of

nanoplankton; large fecal bands, transport ofnano- and picoplankton to deep-sea; single orcolonies

Appendicularia


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Appendicularia

Pelagic Salps


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Pelagic Salps

Arthropoda: crustacean zooplankton


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Cladocera (water fleas): six marine species (Podon

spp., Evadnespp.), one brackish water species in theBaltic Sea; fast reproduction by parthenogenesis(without males and egg fertilization) and pedogenesis(young embryos initiate parthenogenetic reproductionbefore hatching)

Amphipoda:less abundant in pelagic environment,common genus Themisto; frequently found onsiphonophores, medusae, ctenophores, salps

Euphausiida:krill; 15-100 mm, pronounced verticalmigration; not plankton sensu strictu; visual predators,fast swimmers, often undersampled because theyescape plankton nets; important as prey for commercialfish (herring, mackerel, salmon, tuna) and whales

(Antarctica)

Amphipoda


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Amphipoda (parasites of gelatinous plankton)


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http://www.imagequest3d.com/catalogue/deepsea/images/l038_jpg.jpg


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Euphasids (krill)

Importance of krill


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Importance of krillin Antarctic foodweb



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Arthropoda: crustacean zooplankton Copepoda:most abundant zooplankton in the oceans,

insects of the sea; herbivorous, carnivorous andomnivorous species

Calanoida:most of marine planktonic species Cyclopoida:most of freshwater planktonic species

Harpacticoida:mostly benthic/near-bottom species

Copepod development: first six larval stages = nauplius(pl. nauplii), followed by six copepodit stages (CI to

CVI)

Tropical species distinct by their long antennae andsetae on antennae and legs (podi)

C d


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Copepods


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http://www.jochemnet.de/fiu/

Herbivorous zooplankton: Grazers


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Herbivorous zooplankton: Grazers

Vertical Distribution


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Epipelagic: upper 200-300 m water column; high diversity, mostly smalland transparent organisms; many herbivores

Mesopelagic = 300 1000 m; larger than epipelagic relatives; largeforms of gelatinous zooplankton (jellyfish, appendicularians) due to lackof wave action; some larger species (krill) partly herbivorous withnightly migration into epipelagic regimes

Oxygen Minimum Zone: 400 800 m depth, accumulation of fecalmaterial due to density gradient, attract high bacterial growth, which inturn attracts many bacterial and larger grazers; strong respirationreduces O2 content from 4-6 mg l-1 to < 2 mg l-1

Bathypelagic: 1000 3000 m depth, many dark red colored, smaller eyes

Abyssopelagic: > 3000 m depth, low diversity and low abundance

Demersal or epibenthic: live near or temporarily on the seafloor; mostlycrustaceans (shrimp and mysids) and fish

Diel Vertical Migration


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Diel Vertical Migration DAILY (diel) vertical migrations over

distances of 800 m

Nocturnal:single daily ascent beginningat sunset, and single daily descent

beginning at sunrise

Twilight:two ascents and descents perday (one each assoc. with each twilight

period) Reversed:single ascent to surface

during day, and descent to max. depthduring night


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Scattering Layer


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g y

Horizontal distribution: patchiness


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Horizontal distribution: patchiness

Exotic Planktonic species


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Exot c Plankton c spec es

New England Ctenophore Black Sea


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Water Tank Ballast

HoloplanktonMeroplankton


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Black Sea Ballast Invasions


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Black Sea Ballast InvasionsMnemiopsis

Black Sea Ballast Invasions
http://www.oceanactions.com/wp-content/uploads/2008/07/mnemiopsis.png


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Black Sea Ballast InvasionsMnemiopsis

Beroe ovata

European Green Crab Carcinus maenas
http://www.imagequest3d.com/catalogue/ctenophores/index.htmhttp://www.oceanactions.com/wp-content/uploads/2008/07/mnemiopsis.png


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European Green rab arc nus maenas

References
http://upload.wikimedia.org/wikipedia/commons/a/ad/Carcinus_maenas_range.pnghttp://www.dfw.state.or.us/MRP/shellfish/crab/large_images/Green-crab_SG_large.gif


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References

http://www.bayjournal.com/95-03/zooplank.htm

http://faculty.washington.edu/cemills

Many links to each group when typinggroup name

Zooplankton Session i

Documents

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