Plankton – Chapter 14 - planescience.weebly.com filePlankton are the basis for all fish life in...
Transcript of Plankton – Chapter 14 - planescience.weebly.com filePlankton are the basis for all fish life in...
2/12/14
1
Plankton – Chapter 14
Ø Phytoplankton Ø Zooplankton Ø Review food webs Ø Motivation for studying plankton Ø How plankton are collected
Review: What is plankton? • Plankton comes from the Greek word Planktos
that translates to “wanderer” or “drifter” • Plankton include plant-like organisms and
animals that float, drift, or have feeble swimming abilities (insufficient for horizontal migration against currents)
• Usually microscopic, but may be large drifting organisms, e.g., jellyfish
• Phytoplankton - kingdom Protista - autotrophs, primary producers, utilize photosynthesis for energy
• Zooplankton - kingdom animalia -heterotrophs (herbivores, carnivores and omnivores; primary and secondary consumers)
2/12/14
2
Three main phytoplankton groups
Diatoms
Dinoflagellates
Coccolithophorids
Diatoms compose the most abundant phytoplankton group in the oceans, they come in two general varieties:
Centric (pillbox shape) Pennate (elongate shape)
Diatoms use silicate to make hard cell walls called ‘frustules’
ET: epitheca
HT: hypotheca
Diatoms may form chains…
What happens to diatoms when they sink to the aphotic zone? What adaptations help them remain in the euphotic zone?
Diatoms may form spines or setae
2/12/14
3
© Jean-Marie Cavanihac 2001
Dinoflagellates are characterized by one or two whip-like flagella used to change orientation in the water (to increase light exposure).
Pyrocystis fusiformis
Dinoflagellates are often bioluminescent, for example:
Florida red tide organism: Karenia brevis
Dinoflagellates may cause red tides…
2/12/14
4
Satellite image of phytoplankton in region where Florida red tides occur
Source: http://www.whoi.edu/science/B/redtide/rtphotos/flaczcs.gif
Target Study Area
See red tide news
Coccolithophorids: use calcium carbonate to form white “shells”
coccolith
Emiliania huxleyi
Black Sea, 2000
Alaska, 1999 E. huxlei blooms: coccolithophore blooms turn the sea milky white
Newfoundland, 1997
2/12/14
5
(photo from SBI project, summer 2003)
In 1997, hundreds of thousands of Short-tailed Shearwaters died in the Bering Sea, probably due
to starvation. What happened?
Krill, food for the Short-tailed Shearwater
Zooplankton
2/12/14
6
Important zooplankton phyla���(Kingdom Animalia)
• Cnidaria - jellyfish, corals • Mollusca - clams, oysters, snails (plankton as
larval forms) • Arthropoda - copepods, crabs, shrimp (plankton as
larval and adult forms) • Echinodermata - starfish, sand dollars, sea urchins
(plankton as larval forms)
Two primary zooplankton categories: ���
1. Holoplankton - planktonic throughout their entire life cycle (e.g., krill, copepods, chaetognaths)
2. Meroplankton - planktonic for only a portion of their life cycle, invertebrate larvae (e.g., bivalves, starfish, barnacles); ichthyoplankton - fish eggs and larvae are also meroplankton
Photos courtesy of C. Guigand, RSMAS
Examples of holoplankton…
Farranula gracilis (copepod) with eggs
Eucalanus sp. female
Euphausiid (krill)
Chaetognath
2/12/14
7
Examples of meroplankton…
Starfish larvae (echinoderm larvae)
Bivalve pediveliger
Gastropod veliger Crab megalop stage
1000 g C
100 g C
10 g C
1g C
Plankton are the basis for all fish life in the oceans, it takes a lot of plankton at the bottom of the food chain to feed a fish at the top.
dinoflagellate
carnivore 2
carnivore 1
herbivore Gen
erat
ion
time
Size
µm mm cm dm - m
days
weeks
months
years Zooplankton lifetimes and sizes in the pelagic ocean
zooplankton
2/12/14
8
Copepods: crustaceans – usually the most abundant zooplankton (from Greek Kope=“oar”, Podos=“foot”, hence oar-footed, referring to their swimming legs) § Herbivores, carnivores and omnivores § Holoplanktonic: entire planktonic life cycle § Migrate vertically day-night (see next slide)
Side view
Mr. Plankton
Night sunrise
http://jaffeweb.ucsd.edu/pages/celeste/Animations/