Transcript Lecture 10 – Apr 3

Cyanophyta and Flagellates
Lecture 10
OVERVIEW
Eubacteria & Protists
• Cyanophyta
• “Phytoplankton”
• Chlorophyta, Phaeophyta, Rhodophyta
Vascular Plants (Gymnosperms & Angiosperms)
• Seagrasses – Hydrocharitaceae & Potamogetonaceae
• Saltmarshes – Poaceae, Juncaceae, etc
• Mangroves – Rhizophoraceae, Avicenniaceae
• Beach & Dune plants
Fan-Shaped Phylogenetic Tree
Falkowski & Raven 2007
Algal pigments
“Endosymbiosis” Theory
• Eukaryotic cells captured and ingested
prokaryotic cells and “tamed” them to become
organelles (Chloroplasts, Mitochondria – have
own DNA).
• Chloroplasts from blue-green algal cells,
• Mitochondria from bacteria
• Flagellum (9+2 microtubules) from motile,
saprophytic prokaryote
• Rhodophyta ingested a Cyanobacteria
(chloroplast with phycobiliproteins)
Organelles and endosymbiosis
During the 1980s, Lynn Margulis proposed the theory of endosymbiosis
to explain the origin of mitochondria and chloroplasts from
permanent resident prokaryotes. According to this idea, a larger
prokaryote (or perhaps early eukaryote) engulfed or surrounded a
smaller prokaryote some 1.5 billion to 700 million years ago.
The basic events in endosymbiosis. Image from Purves et al., Life: The Science of
Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman
(www.whfreeman.com), used with permission.
Falkowski & Raven 2007
“Cyanophyta”
• = cyanobacteria or bluegreen algae
• Prokaryote Eubacteria–
organelles lacking
• Unicellular, colonial,
filamentous forms
• Chl a + Phycocyanin
(blue), Phycoerythrin
(red), Zeaxanthin
• Heterocysts & N-fixation
• http://wwwcyanosite.bio.purdue.edu
Heterocysts – N fixation
Triple layer cell wall:
glycolipid and polysaccharide
NH4
N2
• Differentiated cell that provides a low O2 environ for Nfixation (nitrogenase)
• Oxygen diffusion 100x lower than normal cell
• No photosystem II – no p’synth
• Higher respiration (uses up O2)
• Under genetic control – up regulated under low N, 1 in 10
cells become heterocysts, within 24 hrs, 600-1000 genes
involved.
http://biology.kenyon.edu/Microbial_Biorealm/bacteria/anabaena/anabaena.htm
http://www2.hawaii.edu/~scallaha/SMCsite/Research.html
Heterocysts – N fixation
Triple layer cell wall:
glycolipid and polysaccharide
NH4
N2
• Differentiated cell that provides a low O2 environ
for N-fixation (nitrogenase)
• Oxygen diffusion 100x lower than normal cell
• No photosystem II – no p’synth
• Higher respiration (uses up O2)
• Under genetic control – up regulated under low N,
1 in 10 cells become heterocysts, within 24 hrs,
600-1000 genes involved.
Cyanophyta
• Stromatolites –
Bermuda, Shark Bay
• 3.5 Bio – 600 Mio
• O2 production – red
bands (FeOx)
• Warm, low energy, low
grazing.
• http://stromatolites
.info/
Cyanophyta
• Stromatolites –
Bermuda, Shark Bay
• 3.5 Bio – 600 Mio
• O2 production – red
bands (FeOx)
• Warm, low energy, low
grazing.
• http://stromatolites
.info/
Cyanophyta
• Stromatolites –
Bermuda, Shark Bay
• Lyngbya
• Oscillatoria
• Scytonema
Cyanophyta
• Stromatolites –
Bermuda, Shark Bay
• Lyngbya
• Oscillatoria
• Nostoc
• Trichodesmium
Div Cyanophyta taxonomy
• Single class: Cyanophyceae.
• No flagellae, no organelles
• No sexual reproduction, use transformation and
conjugation (bacterial recombinant process)
• Mostly freshwater, some marine and terrestrial
habitats (including glaciers, hot springs, etc.)
• 150 genera, 2000 spp
• Prefer warm, quiescent water, often higher
salinities.
• Important members of the picoplankton (0.2-2um)
• 5 Orders: Chroococcales, Pleurocapsales,
Oscillatoriales, Nostocales, Stigonematales
“Thallus” organization
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Unicells – Chroococales
Colonial – Pleurocapsales
Filamentous – Oscillatoriales, Nostocales
Simple parenchymatous – Stigonematales
• Two taxonomic systems:
• Geitler (1932) based on morphology
• Stanier (1977) based on axenic clonal culture
(bacteriological techniques)
http://tolweb.org/Cyanobacteria/2290
http://www-cyanosite.bio.purdue.edu/images/images.html
Or. Chroococales
Chroococcus
Microcystis
Or. Pleurocapsales
Cyanocystis
Pleurocapsa
Black bands on seashore rocks
Or. Oscillatoriales - Stromatolites
Lyngbya
Trichodesmium
Lyngbya
Oscillatoria
Microcoleus
Heterocysts
Or. Nostocales
Nostoc
Anabaena
Autofluorescence image
Or. Stigonematales
Fisherella
Microbial Mats
http://www.marine.unc.edu/Paerllab/sansalmo/index.htm
Cyanophyta summary
• Prokayotic Eubacteria
• Simplest photosynthesizers – stromatolites
and atmospheric oxygen
• N-fixation in heterocysts
• Oscillatoriales most important marine
order.
• Can form blooms: toxins, anoxia
• Microbial Mats important area of research
“Phytoplankton”
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Passive floating
Photic Zone (0-100m depth = 0.1% PAR)
Diurnal Vertical Migration (DVM)
Sampling – Plankton Net (mesh = 4076mm mesh size, silk or nylon).
• 30 yr N. Atl dataset - Continuous Plankton
Records (CPR): Plankton Atlas of the
North Atlantic Ocean (1958–1999). MEPS
Suppl. 3, 2004.
“Phytoplankton”
• Size: net- (40-80+mm), nanno- (2-20mm),
pico- (0.2-2mm), ultra- (<0.2mm)
• Filtering, microscopy cell counts.
• 47 Pigments: chls + accessory pigments
• Analysis by HPLC (High Performance
Liquid Chromatography)
• Pigments have potential use in Remote
Sensing of presence/concentration
“Phytoplankton”
• Unicells
• Filamentous
• Colonies – chains, or spheres
Flagellates
• Mixed bag taxonomically, includes
“picoplankton (<2mm)”
• “naked” – don’t preserve well, need to be
studied while living
• Size <1mm – 1mm
• >1x109 cells / Liter in blooms!
• Ubiquitous, poorly studied to date
Flagellates
Euglena
Flagellum
• 2 central + 9 axial
microtubules
• Single or paired
• Anterior, posterior
flagellum
• Smooth or “hairy”
• Basal body =
anchoring structure
Flagellum
• 2 central + 9 axial
microtubules
• Single or paired
• Anterior, posterior
flagellum
• Smooth or “hairy”
• Basal body =
anchoring structure
Flagellates
• Division Chlorophyta
• Class:
– Euglenophyceae
– Prasinophyceae
– Chlorophyceae Chlamydomonas
• Chl a + b
• Division Chromophyta
– Cryptophyceae
• Division Heterokontophyta
– Dinophyceae (naked
Dinoflagellates)
– Raphidophyceae
– Chrysophyceae
– Xanthophyceae
– Dictyochophyceae
– Prymnesiophyceae
• Chl a + accessory
pigments (carotenoids)
Class Euglenophyceae
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Can also be placed in Div. Euglenophyta
Chl a+b
Eyespot
Mainly FW, some marine
6 orders, 40 genera, 800 spp
Heterotrophy important
Class Euglenophyceae
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Single Class – Euglenophyceae
Chl a+b
Eyespot
Mainly FW, some marine
6 orders, 40 genera, 800 spp
Heterotrophy important
Class Prasinophyceae
• 4 Orders, 16 genera, 180 spp
• Cells with 1-8 flagellae
• Bathycoccus - picoplankton (0.5-2um), N.
Atlantic
• Pterosperma - large (100-800um) cystlike stages = phycomata. Fossil cysts from
1.2 Bya.
Class Prasinophyceae
• 4 Orders, 16 genera, 180 spp
• Cells with 1-8 flagellae
• Bathycoccus - picoplankton (0.5-2nm), N.
Atlantic
• Pterosperma - large (100-800nm) cystlike stages = phycomata. Fossil cysts from
1.2 Bya.
Class Chlorophyceae
• 4 orders, 355 genera, 2650 spp – only v few marine.
• Or Volvocales – unicell & colonial, Chlamydomonas,
Volvox
• Or Chlorococcales – unicell -> siphononous,
Chlorella (1-2um), endosymbiont in tropical foramifera,
Scenedesmus (brackish, eutrophic)
• Or Chaetophorales – no marine spp
• Or Oedogoniales – filamentous,
Oedogonium 400spp
Class Chlorophyceae
• 4 orders, 355 genera, 2650 spp – only v few marine.
• Or Volvocales – unicell & colonial, Chlamydomonas,
Volvox
• Or Chlorococcales – unicell -> siphononous,
Chlorella (1-2um), endosymbiont in tropical foramifera,
Scenedesmus (brackish, eutrophic)
• Or Chaetophorales – no marine spp
• Or Oedogoniales – filamentous,
Oedogonium 400spp
Flagellates
• Division Chlorophyta
• Class:
– Euglenophyceae
– Prasinophyceae
– Chlorophyceae Chlamydomonas
• Chl a + b
• Division Chromophyta
– Cryptophyceae
• Division Heterokontophyta
– Dinophyceae (naked
Dinoflagellates)
– Raphidophyceae
– Chrysophyceae
– Xanthophyceae
– Dictyochophyceae
– Prymnesiophyceae
• Chl a + accessory
pigments (carotenoids)
Class Cryptophyceae
• 12 genera, 200 spp, ½ marine
• Biflagellate, ventral gullet with trichocysts,
accessory pigments (phycobilins,
xanthophylls, carotenes)
• Dominate nannoplankton (2-20um) in
North Sea spring blooms – Cryptomonas
• Massive blooms of Mesodinium in
upwelling zones (Peru, Baja California)
Class Cryptophyceae
• Class Cryptophyceae – 12 genera, 200
spp, ½ marine
• Biflagellate,
ventral gullet with trichocysts,
Cryptomonas
accessory pigments (phycobilins,
xanthophylls, carotenes)
• Dominate nannoplankton (2-20um) in
North Sea spring blooms – Cryptomonas
• Massive blooms of Mesodinium in
upwelling zones (Peru, Baja California)
Class Raphidophyceae
• Heterokont = long tinsel flagellum anterior,
short smooth flag posterior
• 1. Class Raphidophyceae – 9 genera.
• Unicell flagellates, 2 flagellae, cells 50100um, curved dorsal side, flattened
ventral side with flagellar groove.
• FW and marine – form HABs in Japan, DE
• Chattonella, Fibrocapsa
Div Heterokontophyta
• Heterokont = long tinsel flagellum anterior,
short smooth flag posterior
• Class Raphidophyceae – 9 genera.
• Unicell flagellates, 2 flagellae, cells 50100um, curved dorsal side, flattened
ventral side with flagellar groove.
• FW and marine – form HABs in Japan, DE
• Chattonella, Fibrocapsa
Chattonella
Fibrocapsa
Class Chrysophyceae
• Unicell, amoeboid, coccoid, filamentous forms
• 2. Class Chrysophyceae, 3 orders, 200 genera,
1000 spp, v. few marine. Includes
Pelagoccocus (picoplankt) and Sarcinochrysis
(estuarine)
• 3. Class Xanthophyceae, 7 orders, 100 genera,
600 spp, few marine. Includes the mat forming
Vaucheria (50 spp) – siphonous construction
Class Xanthophyceae
• Unicell, amoeboid, coccoid, filamentous forms
• Class Chrysophyceae, 3 orders, 200 genera,
1000 spp, v. few marine. Includes
Pelagoccocus (picoplankt) and Sarcinochrysis
(estuarine)
• Class Xanthophyceae, 7 orders, 100 genera,
600 spp, few marine. Includes the mat forming
Vaucheria (50 spp) – siphonous construction
10 um
Pelagococcus
Vaucheria (from GCRL)
Class Dictychophyceae
• 4. Class Dictyochophyceae – 2 spp extant
• Single flagellum with mastigonemes
(hairs). Siliceous skeleton (fossilizes well),
120 Mya evolved (silicoflagellates)
• More prevalent cooler waters. Used to
estimate historic SST.
• Dictyocha fibula and D. speculum
Div Heterokontophyta
• Class Dictyochophyceae – 2 spp extant
• Single flagellum with mastigonemes
(hairs). Siliceous skeleton (fossilizes well),
120 Mya evolved (silicoflagellates)
• More prevalent cooler waters. Used to
estimate historic SST.
• Dictyocha fibula and D. speculum
Dictyocha
Summary
• Flagellates part of phytoplankton – often
picoplankton, poorly studied, don’t
preserve well, very small, hard to ID
• 2 groups – green pigments (Div
Chlorophyta), brown pigments (Div
Chromophyta / Heterokontophyta)
• Some groups prone to blooms and HABs