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Phycology: The Study of Algae
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Some restricted to marine environment (reds and browns), some to freshwater
Characterized by morphology, biochemistry, pigments, reproductive methods, food reserves
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Photosynthetic Pigments
Chlorophylls Chlorophyll -found in all algae and macrophytes; the primary pigment Absorbance spectrum nm and 430 nm Chlorophyll -only in chlorophyta, euglenophyta and charophyta; Absorbs about 435 nm and 645 nm Chlorophyll c- accessory pigment Absorbs , , and nm.
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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
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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
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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
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Coloration of flamingoes and shrimp
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
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Merismopedia Nostoc balls Oscillatoria Spirulina
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Microcystis Rivularia Lyngbia Scytonema false branching
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Diatoms
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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)
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Pennales: pennate diatoms
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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;
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Green Algae: Chlorophytes
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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
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Irish Moss (Chondrus crispus)
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Porphyra (Nori)
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Dulse (Palmaria palmata)
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Predominantly marine group
Few FW representatives, especially locally Not necessarily ‘red’ in appearance Complex life cycles
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Batrachospermum
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Characteristic of cool, clear streams
Bangia atropurpurea Characteristic of cool, clear streams
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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
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General Structure
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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
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Ceratium
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Red Tide
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Red Tide In marine ecosystems, can cause paralytic shellfish poisoning (PSP) Gonyaulax tamarensis
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Noctiluca, sea sparkle Pfisteria
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Brown algae Not plants 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
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Cladophora Branching filaments; often forms mats
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Chloroplasts often distinctive to the genus
Spirogyra-spirals Mougeotia-plates; can orient Ulothrix-’apple core’ Zygnema-stellate
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Flagellated forms Chlamydomonas Eudorina Pandorina Volvox
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Euglena
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Chrysophyta: Golden Browns
Eukaryotic Pigments: chlorophyll a & b, carotenoids, fucoxanthin Food storage: chrysolaminarin, oils Cell wall: cellulose One or two flagella may be present
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Cluster of biflagellate cells
Golden brown (not green like similar looking green algae) No division of labor between cells
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Vaucheria
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Dinobryon Constructs a cellulose lorica
Diploid zygote can act as resting stage that can last for years Locally common
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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
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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
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Monitoring Algae Note water color: Brown: diatoms
Bluish green: blue-greens e.g., Microcystis or Oscillatoria Bright green: Euglena-types, Volvox
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Monitoring Algae (cont.)
Note water clarity: Microscopic ‘cut grass’ --->Aphanizomenon
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Remember . . . some algae is desirable!
Types: Single-celled/phytoplankton diatoms, greens, blue-greens Colonial/phytoplankton Euglena, Volvox Filamentous Spirogyra, Oscillatoria
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