Phycology: The Study of Algae

1. Phycology: The Study of Algae

2. Some restricted to marine environment (reds and browns), some to freshwater • Characterized by morphology, biochemistry, pigments, reproductive methods, food reserves

3. 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.

5. 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

6. 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

7. Cyanophytes (continued) • Nutrition: • Mostly autotrophic, some saprophytic • 40 different kinds are N-fixers; all of these have heterocysts; do well in N-poor environments • AphanizomenonAnabaenaNostoc

8. 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

9. Merismopedia Nostoc balls Oscillatoria Spirulina

11. Microcystis Rivularia Lyngbia Scytonema false branching

13. Diatoms

15. 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)

16. Pennales: pennate diatoms

17. 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;

18. Green Algae: Chlorophytes

21. 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

22. Irish Moss (Chondrus crispus)

23. Porphyra (Nori)

24. Dulse (Palmaria palmata)

25. Predominantly marine group Few FW representatives, especially locally Not necessarily ‘red’ in appearance Complex life cycles

26. Batrachospermum

27. Bangia atropurpurea Characteristic of cool, clear streams

28. Dinoflagellates

29. 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

30. General Structure

31. 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

32. Ceratium

33. Red Tide

34. Red Tide • In marine ecosystems, can cause paralytic shellfish poisoning (PSP) Gonyaulax tamarensis

35. Noctiluca, sea sparkle Pfisteria

36. Brown algae • Conspicuous seaweeds of northern regions • Life cycle involves alternation of generations • Sporophyte – multicellular and diploid • Gametophyte – multicellular and haploid • Not plants

38. Chlorophyta: Green Algae

39. Cladophora Branching filaments; often forms mats

40. Chloroplasts often distinctive to the genus Spirogyra-spirals Mougeotia-plates; can orient Ulothrix-’apple core’ Zygnema-stellate

41. Flagellated forms Chlamydomonas Eudorina Pandorina Volvox

42. Euglena

44. Chrysophyta: Golden Browns • Eukaryotic • Pigments: chlorophyll a & b, carotenoids, fucoxanthin • Food storage: chrysolaminarin, oils • Cell wall: cellulose • One or two flagella may be present

45. Cluster of biflagellate cells • Golden brown (not green like similar looking green algae) • No division of labor between cells

46. Vaucheria

47. Dinobryon • Constructs a cellulose lorica • Diploid zygote can act as resting stage that can last for years • Locally common

48. 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

49. 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

50. Monitoring Algae • Note water color: • Brown: diatoms Bluish green: blue-greens e.g., Microcystis or Oscillatoria • Bright green: Euglena-types, Volvox