Plankton

Picoplankton: Viruses, archaea, bacteria

(Text Fig. 14-25, p. 422)

• • Fluorescent image of open-

ocean water sample showing marine viruses (small dots) and either bacteria or archaea (large dots).

• Most viruses are <0.2 µm.

• Picoplankton (which include cyanobacteria) may contribute up to 70% of photosynthetic activity in some ocean regions.

• So small that they were not even recognized by oceanographers until mid 1970’s.

The three main phytoplankton groups

(Text Fig. 14-10, p. 405)

1) Diatoms1) Diatoms (silica skeletons, non-swimming) (silica skeletons, non-swimming)

2) Dinoflagellates2) Dinoflagellates(cellulose skeletons,(cellulose skeletons,swim with flagella)swim with flagella)3) Coccoliths3) Coccoliths (calcareous skeletons, (calcareous skeletons,

non-swimming)non-swimming)

Diversity of protist phytoplanktonDinoflagellatesDinoflagellates (naked or cellulose skeletons) (naked or cellulose skeletons)

DiatomsDiatoms (silica skeletons) (silica skeletons)

CeratiumCeratium

NoctilucaNoctiluca: luminescent: luminescent

Deadly phytoplankton: Red-tide dinoflagellates

Gonyaulax: Produces “Red-tides”

“Red-tide” Cortes Island, BC

concentrated dinoflagellates in digestive gland

concentrated dinoflagellates in digestive gland

A “blood-oyster” following a red-tide in Cortes Island, BC (photos by Christian Gronau)

Diversity of protist zooplankton

foramforam Ostracod!Ostracod!

ForaminiferaForaminifera: chambered, mostly calcareous skeleton: chambered, mostly calcareous skeleton RadiolariaRadiolaria: radial, mostly silica skeleton: radial, mostly silica skeleton

spine-like axoopodsspine-like axoopods

Mostly from: Image Quest 3-D (Mostly from: Image Quest 3-D (http://imagequest3d.com))

HeliozoaHeliozoa

Mesozooplankton: Copepods- the most numerous animals on earth

prey captureprey capture

swimming & attack behaviorswimming & attack behavior

Animations:Animations:

(Text Fig. 15-5, p. 429)

mating pair

male

female

Copepods may be grazers (primary consumers) or

predators (secondary consumers)

female with eggs

Gelationous mesoplankton & macroplankton

(Text Fig. 15-8, p. 431)

CtenophoreCtenophore: : PleurobrachiaPleurobrachia

Colonial salps (Urochordata)Colonial salps (Urochordata): : SalpaSalpa

Macrozooplankton: Ctenophora (sea gooseberries)

(Roger Steene, “Coral Seas”, 1998)(Roger Steene, “Coral Seas”, 1998)Sea-butterfly, Sea-butterfly, OcyropsisOcyropsis

TheThevoraciousvoracious

predator, predator, BeroeBeroe; ; swallows other swallows other

ctenophores wholectenophores whole(Roger Steene, (Roger Steene,

“Coral Seas”, 1998)“Coral Seas”, 1998)

CestusCestusPleurobranchiaPleurobranchia

Unnamed Unnamed deep-sea deep-sea

speciesspeciesMnemiopsisMnemiopsis

(note 2 long, (note 2 long, branched tentacles)branched tentacles)

comb rowscomb rows

Other mesoplankton & macroplankton: Chaetognaths

(Text Fig. 15-9, p. 432)

ChaetognathaChaetognatha: arrow worm: arrow worm

Chaetognaths are major predators on small zooplankton.

Macrozooplankton: Krill (Crustacea)

Krill (euphausiid shrimp) are major primary consumers in the world’s Southern Oceans. They, in turn, are important prey for baleen whales because they may form swarms that are

kilometers across . . . visible from an airplane!

Adaptations to reduce sinking

(Text Fig. 13-9, p. 381)

A warm-water diatom that has a prominent marginal ring to increase its surface area and

reduce its rate of sinking

(Text Fig. 13-7, p. 380)

Characteristic forms of warm-water (left)and cold-water (right) copepods

end