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