Plankton Communities Plankton are free floating and weak swimmers whose position is determined by...
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Transcript of Plankton Communities Plankton are free floating and weak swimmers whose position is determined by...
Plankton Communities
Plankton are free floating and weak swimmers whose position is determined by water movements- phytoplankton and zooplankton
Nekton are strong swimmers who are able to determine the position regardless of the water’s movements
Size Classification of PlanktonSize Classification of Plankton
• Femtoplantkon - < 0.2 μm
• Picoplankton - 0.2 to 2 μm
• Nanoplankton - 2 to 20 μm
• Microplankton - 20 to 200 μm
• Macroplankton - 200 to 2000 μm
• Megaplankton - > 2000 μm
Size Classification of PlanktonSize Classification of Plankton• Femtoplankton – mostly viruses
• Picoplankton
phototrophic bacteria and cyanobacteria
prochlorophytes
heterotrophic bacteria
chemoautotrophic bacteria
eukaryotic picoflagellates
• Nanoplankton
heterotrophic nanoflagellates (HNANs)
small prokaryotic and eukaryotic phytoplankton
• Microplankton
prokaryotic and eukaryotic phytoplankton
heterotrophic flagellates and ciliates
most small zooplankton and larvae
Note that the size relationship between bacteria and a ciliate is like krill is to a whale!
Plankton are usually separated into categories based on their size.
Community Composition
Come in all shapes and sizes (morphology and size limitations) single cells, chains, filaments
some are mixotrophic (both photo and heterotrophic)
Major Groups
Non-Motile Motile (flagella)
Cyanobacteria Chlorophytes PrasinophytesDiatoms Prymnesiophytes
CryptophytesDinoflagellates EuglenophytesChrysophytes (coccolithophorids
and silicoflagellates)
PhytoplanktonPhytoplankton
Diatoms have heavy silicified (pectin and amorphous silica) frustules
• Are heavy than water, sink rapidly
• Usually the most abundant group (>80% of biomass) in
estuarine and near-coastal waters
PhytoplanktonPhytoplankton
From Sverdrup et al. 2004
DiatomsDiatomsFrom Phytopia
Chaetoceros debilis
Chaetoceros socialis
Ditylum brightwellii
Thalassionema sp.
PhytoplanktonPhytoplankton
PhytoplanktonPhytoplankton
DinoflagellatesDinoflagellatesHave 2 flagellaMany species are mixotrophicMost harmful algal species are dinoflagellates
From Sverdrup et al. 2004
From Phytopia
PhytoplanktonPhytoplankton
DinoflagellatesDinoflagellates
Dinophysis sp.
Protoperidinim divergens
Paralytic Shellfish Poisoning
Neurotoxic Shellfish Poisoning
Brown Tide Blooms
Amnesic Shellfish Poisoning
Pseudonitszia
Harmful Algal Blooms
Pfiesteria piscicida
MicroflagellatesMicroflagellates
PhytoplanktonPhytoplankton
From Miller 2004
Chlorophyceae
Cryptophyceae
ChrysophyceaeHaptophyta
Prasinophyceae
PhytoplanktonPhytoplankton
PicoplanktonPicoplankton• Are some of the smallest primary producers (0.2 – 2 µm dia.)• Were not discovered until the early 1980’s• Important contributors to oceanic primary production• Are usually most abundant at the chlorophyll max in the open ocean• Major groups are…
Cyanobacteria (Synechococcus)Prochlorophytes (Prochlorococcus)
http://plantbio.berkeley.edu/~volkman/courses/MCB116Slides/Lec1Slide19.jpg
PicoplanktonPicoplankton
DAPI DNA stain
Epifluorescent Microscope
Under UV light
Particles contain DNA
DAPI DNA stain
Epifluorescent Microscope
Under blue light
Red cells are Prochlorococcus
Yellow cells are Synechococcus
Big yellow cell is a dinoflagellate
From Kaiser et al. 2005
Prochlorophytes
Very recently discovered, prochlorophytes are extremely small photosynthetic organisms that are the most abundant plants (by cell #) on earth.
These tend to live in deeper waters near the base of the sunlit layer.
Prochlorophytes
Cryptophytes
Chl a + ca-carotenePhycobilins
Chl a + bb-caroteneXanthophylls
• In most estuaries, Nanoplankton have the highest biomass and primary production
• In oligotrophic habitats, Picoplankton have the highest biomass and primary production
• Occasional blooms of microphytoplankton occur under nutrient enriched conditions
PhytoplanktonPhytoplankton
Benthic Microalgae (microphytobenthos)
• Production: up to 2kg C m-2 yr-1
• Very high biomass: 0.1(?) kg C m-2
• Turnover (P/B): ~20(?)
Dinoflagellates: Naked and Armored
Cell densities up to 104-106 l-1 (Blooms)
Coastal Phytoplankton
• Production: up to 0.5 kg C m-2 yr-1
• Low biomass: 0.02 kg C m-2
• HIGH Turnover (P/B): ~25
Chl a + cb-carotenexanthophylls (peridinin)
‘Blue-green algaeTrichodesmiumN2 fixation
Heterocyst
Cell densities up to 101-103 l-1 (Blooms)
Shelf-Oceanic Phytoplankton
• Production: up to 0.1 kg C m-2 yr-1
• Very low biomass: 0.003 kg C m-2
• VERY HIGH Turnover (P/B): ~40
Chl ab-carotenePhycobilins (phycocyanin)
23 Feb 1997
~50% Production trapped on the continental shelf
Abundances
General trends:
Phytoplankton most abundant near coasts, decreasing with distance
Where seasonal effects are important (higher attitudes), highest abundances in springtime
Trends with distance
Species composition varies with distance from land. Near-shore waters dominated by diatoms. Offshore waters have much higher percentages of dinoflagellates and coccolithophorids.
Note: This picture can change with season and conditions.
CoccolithophoresCaCO3
~50% spread over vast ocean