Transcript Phycology: The Study of Algae

Phycology: The Study of Algae
• Some restricted to marine environment
(reds and browns), some to freshwater
(our focus)
• Characterized by morphology,
biochemistry, pigments, reproductive
methods, food reserves
Photosynthetic Pigments
• Chlorophylls
– Chlorophyll a-found in all algae and
macrophytes; the primary pigment
• Absorbance spectrum 660-665 nm and 430 nm
– Chlorophyll b-only in chlorophyta,
euglenophyta and charophyta;
• Absorbs about 435 nm and 645 nm
– Chlorophyll c- accessory pigment
• Absorbs 630-635, 583-586, and 444-452 nm.
Accessory Pigments
• Carotenes- and  are most common
• Xanthophylls-derivatives of carotenes
– E.g., lutein, diatoxanthin, myxoxanthin,
peridinin
• Biliproteins-almost exclusively in
cyanophyta
– E.g., phycocyanin, phycoerethryin
Cyanophyta (Blue-green algae)
• are prokaryotic bacteria; date to 3.5 BYA
• ~55% are blue-green
• ~15% are never blue-green; others may be green, olive, red, purple,
black, or colorless
• Store food as glycogen (iodine negative)
• Never flagellate, but some can move (oscillate or glide)
• Reproduction
– Sexual-not known
– Vegetative-binary fission; fragmentation
– Asexual
• Akinete-germinates directly
• Heterocyst-may divide either directly to a trichome or to endospores which
‘germinate’ to a trichome
• Presence of pseudovacuoles; gas-filled; affect buoyancy; may
shade other species
Cyanophytes (continued)
• Nutrition:
– Mostly autotrophic, some saprophytic
– 40 different kinds are N-fixers; all of these
have heterocysts; do well in N-poor
environments
• Aphanizomenon Anabaena
Nostoc
• Distribution-highly successful; terrestrial,
aquatic, marine, epiphytic, on walls, soils,
parasitic, planktonic; some can live at 80oC.
• Economic importance
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Rice paddy nitrogen fixation
Nostoc balls
Odors and flavors-musty, moldy
Allergies
• Coloration of flamingoes and shrimp
Merismopedia
Nostoc balls
Oscillatoria
Spirulina
Microcystis
Rivularia
Lyngbia
Scytonema false branching