Post on 15-Dec-2015
Phycology: The Study of Algae
• Some restricted to marine environment (reds and browns), some to freshwater
• Characterized by morphology, biochemistry, pigments, reproductive methods, food reserves
Photosynthetic Pigments
• Chlorophylls– Chlorophyll -found in all algae and
macrophytes; the primary pigment• Absorbance spectrum 660-665 nm and 430 nm
– Chlorophyll -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– Rice paddy nitrogen fixation– Nostoc balls– Odors and flavors-musty, moldy– Allergies
• Coloration of flamingoes and shrimp
Merismopedia
Nostoc balls
SpirulinaOscillatoria
Lyngbia
MicrocystisRivularia
Scytonema false branching
Diatoms
Centrales: centric diatoms
•Radial symmetry
•Striae composed of linear punctae
•May be single-celled like Cyclotella (above) or colonial: in filaments or like Tabellaria (above)
Pennales: pennate diatoms
Pennales• Bilateral symmetry• Many groups possess a raphe-these are motile;
some have a pseudoraphe• Generalization: pennate diatoms are more
common in eutrophic waters, centrics in oligotrophic waters;
Green Algae: Chlorophytes
Rhodophyta: Red Algae
• Eukaryotic
• Pigments: chlorophyll a & b, phycoerythrin
• Food storage: iodine negative starch
• Cellulose cell walls
• No flagellated cells
• Many marine species often used as thickeners due to their highly mucilaginous nature: agar, carageenans
Irish Moss (Chondrus crispus)
Porphyra (Nori)
Dulse (Palmaria palmata)
• Predominantly marine group
• Few FW representatives, especially locally
• Not necessarily ‘red’ in appearance
• Complex life cycles
Batrachospermum
Bangia atropurpurea
Characteristic of cool, clear streams
Dinoflagellates
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Dinoflagellates
• Photosynthetic, unicellular with flagella• Live in aquatic environments• Some are luminescent• Do not appear to be directly related to any other phylum• “Red tide” are “blooms” – fish, birds, and marine
mammals may die from toxins• DNA not complexed with histones
General Structure
General Characteristics
• Most are solitary
• Most have two flagella of unequal length
• Cellulose cell wall of plates; or naked
• Ceratium-blooms color water brown, have fish/septic odor
Ceratium
Red Tide
Red Tide
• In marine ecosystems, can cause paralytic shellfish poisoning (PSP)
Gonyaulax tamarensis
Pfisteria Noctiluca, sea sparkle
Brown algae
• Conspicuous seaweeds of northern regions
• Life cycle involves alternation of generations– Sporophyte – multicellular
and diploid– Gametophyte –
multicellular and haploid
• Not plants
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Chlorophyta: Green Algae
Cladophora
Branching filaments; often forms mats
Chloroplasts often distinctive to the genus
Spirogyra-spirals Mougeotia-plates; can orient
Ulothrix-’apple core’ Zygnema-stellate
Flagellated forms
ChlamydomonasEudorina
Pandorina
Volvox
Euglena
Chrysophyta: Golden Browns
• Eukaryotic
• Pigments: chlorophyll a & b, carotenoids, fucoxanthin
• Food storage: chrysolaminarin, oils
• Cell wall: cellulose
• One or two flagella may be present
•Cluster of biflagellate cells
•Golden brown (not green like similar looking green algae)
•No division of labor between cells
Vaucheria
Dinobryon
•Constructs a cellulose lorica
•Diploid zygote can act as resting stage that can last for years
•Locally common
Factors affecting algal growth
Remember: they are plants!
•Amount of sunlight received: turbidity & water clarity
•require nutrients (fertilizers) P and N
•water temperature; some are seasonal; heat and chemistry
•sinking or flushing
•grazing
•competition from other plants for limited materials
Problems from Algae
Aesthetics: who wants a scum-covered pond?
Reduces water clarity
Taste and odor: from fish to pigsty
Mats clog propellers and cost you lures!
Swimming: aesthetics and safety
Can form rotting masses:
odor and oxygen problems
Monitoring Algae
Note water color:
Brown: diatoms
Bright green: Euglena-types, Volvox
Bluish green: blue-greens e.g., Microcystis or Oscillatoria
Note water clarity:
Microscopic ‘cut grass’ --->Aphanizomenon
Monitoring Algae (cont.)
Algae
Types:• Single-celled/phytoplankton
– diatoms, greens, blue-greens
• Colonial/phytoplankton– Euglena, Volvox
• Filamentous– Spirogyra, Oscillatoria
Remember . . . some algae is desirable!