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

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

Merismopedia Nostoc balls Oscillatoria Spirulina

Microcystis Rivularia Lyngbia 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

Characteristic of cool, clear streams Bangia atropurpurea Characteristic of cool, clear streams

Dinoflagellates

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

Noctiluca, sea sparkle Pfisteria

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

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 Chlamydomonas Eudorina 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 Bluish green: blue-greens e.g., Microcystis or Oscillatoria Bright green: Euglena-types, Volvox

Monitoring Algae (cont.) Note water clarity: Microscopic ‘cut grass’ --->Aphanizomenon

Remember . . . some algae is desirable! Types: Single-celled/phytoplankton diatoms, greens, blue-greens Colonial/phytoplankton Euglena, Volvox Filamentous Spirogyra, Oscillatoria