1. Chlorophyta (green algae) Lecture 8

2. OVERVIEW Eubacteria & Protists Cyanophyta “Phytoplankton” Chlorophyta, Phaeophyta, Rhodophyta Vascular Plants (Gymnosperms & Angiosperms) Seagrasses – Hydrocharitaceae & Potamogetonaceae Saltmarshes – Poaceae, Juncaceae, etc Mangroves – Rhizophoraceae, Avicenniaceae Beach & Dune plants

3. Fan-Shaped Phylogenetic Tree

4. “MACRO-ALGAE” = seaweeds Divisions: –Chlorophyta (green) –Phaeophyta (brown) –Rhodophyta (red) Separated on basis of pigments (color) Evolved 900-600 Mio (Cambrian) Continental Margins – Rocky shores or lagoons predominantly.

5. Div Chlorophyta –Chlorophyta (green) – 900 spp (about 10% of known spp, rest are freshwater). –Ancestor of terrestrial plants (Kingdom Plantae) –Chl a + b, (B-carotene, xanthophylls – photoprotective role) –Uni-nucleate, also Multi-nucleate (siphonous) –6 Orders: e.g. Ulvales, Cladophorales, Caulerpales –Cosmopolitan and tropicals

6. Algal pigments

7. Pigment Molecules CHLOROPHYLL CAROTENES

8. Epiphytes Cladophora Enteromorpha Chaetomorpha

9. UlvaEnteromorpha HalimedaCaulerpa

10. THALLUS SHEET COARSLEY - BRANCHED JOINTED - CALCAREOUS THICK - LEATHERY FILAMENT ENCRUSTING

11. Form - Function Incr productivity

12. UlvaEnteromorpha HalimedaCaulerpa

13. Why simple = more productive? Nutrient uptake, waste removal in single cell relies on diffusion, some active uptake. No translocation within plant necessary Reduce boundary layer effects – promotes diffusion into cell. No metabolic losses to structural tissues Faster life-cycle (hrs – days)

14. Boundary Layers Zone of little-no flow around an object/surface. Inhibits diffusion Movement promotes flow past object, breaking down boundary layer Important for algal nutrient and CO 2 uptake

15. Boundary Layers Zone of little-no flow around an object/surface. Inhibits diffusion Movement promotes flow past object, breaking down boundary layer Important for algal nutrient and CO 2 uptake Diffusion across cells/membranes

16. Simple Structure and Succession r vs K selected life- strategies r = Ulva, Enteromorpha K = Halimeda, Penicillus Taxonomy generally from simple to complex: single cells, filaments, multi-filament, corticated, specialized structures

17. Chlorophyte taxonomy Number of classes has increased from 1 in 1903, to 3 in 1990, to 10 in 1995. Based on EM (2 types of cell division, flagellum ultrastructure) and RNA sequence in chloroplast and mitrochondria, DNA in nuclei. Ancestors of terrestrial vascular plants Class Prasinophyceae – single cell (plankton). Class Chlorophyceae – 6 of 15 orders have seaweeds.

18. Thallus organization Unicell flagellate – Chlamydomonas Colonial flag – Volvox Tetrasporal, Coccoid, Sarcinoid groups Filamentous – Ulothrix Thallose – Ulva Siphonous - Caulerpa

19. Evolution Chlamydomonas VOLVOX Spyrogyra

20. Chara - muskgrass

21. Chlorophyceae taxonomy (recent) Or. Ulvales (Ulotrichales) – Fam. Ulvaceae + 5 others Cladophorales – Cladophoraceae + Anadyomenaceae Acrosiphoniales – 1 order Siphonocladales – Siphonocladaceae, Boodleaceae, Valoniaceae Caulerpales – Bryopsidaceae, Caulerpaceae, Codiaceae, Udoteaceae, + 2 others (FW) Dasycladales – Dasycladaceae + Acetabulariaceae

22. Cl. Chlorophyceae taxonomy Dawes, pg 122

23. Or. Ulvales Ulva

24. Or. Ulvales Enteromorpha

25. Or. Cladophorales Cladophora

26. Or. Cladophorales Anadyomene

27. Or. Siphonocladales Boodlea Siphonocladus

28. Or. Siphonocladales Holdfast Valonia

29. Or. Caulerpales

31. Caulerpa mexicana

32. Or. Caulerpales

33. Codium

34. Or. Caulerpales - rhizophytic “root-ball”

35. Or. Caulerpales

36. Halimeda

37. Or. Dasycladales Dasycladus Batophora

38. Or. Dasycladales Acetabularia

39. MS Chlorophyta (1957) Ulvales – Enteromorpha flexuosa, E. lingulata, E. plumosa, Ulva lactuca –Ulotrichaceae – Stichooccus marinus –Chaetophoraceae – Entocladia viridis, Phaeophila floridaerum, Ulvella lens Cladophorales – Cladophora fascicularis, C gracilis, Rhizoclonium riparium. Siphonales – Osterobium queketti about 12 species…

40. Chlorophyta in the “news” Ulva and Enteromorpha abundance increases in Baltic Sea / Adriatic Sea due to eutrophication – smothering seagrass and mudflats, smelly wrack driving tourists from beaches. Enteromorpha bloom in China largest ever recorded – thought to originate from aquaculture. Caulerpa taxifolia – Killer Algae escapes Monaco aquarium. Covers 10’000acres in Med within <10years. Halimeda and Dictyota (brown) smother Fla Keys reef tract – response to eutrophication from septic systems? Acetabularia used in studies of abiotic and genetic cues for algal development.

41. Chlorophyta in the “news” Ulva and Enteromorpha abundance increases in Baltic Sea / Adriatic Sea due to eutrophication – smothering seagrass and mudflats, smelly wrack driving tourists from beaches.

42. Enteromorpha bloom seen from space! (Liu et al. 2009)

43. Cause: more aquaculture of seaweed (Porphyra) for sushi. Green algae a by-product. Ocean circulation moved bloom of green algae north and east, so accumulates onshore far from source population.

44. Chlorophyta in the “news” Caulerpa taxifolia – Killer Algae escapes Monaco aquarium. Covers 10’000acres in Med within <10years. http://aquat1.ifas.ufl.edu/seagrant/cautax2.html

45. Chlorophyta in the “news” Halimeda and Dictyota (brown) smother Fla Keys reef tract – response to eutrophication from septic systems? Orange Bay, Jamaica. Eutrophication from sugar cane fields

46. SAND KEY, FLA

47. Chlorophyta in the “news” Acetabularia used in studies of abiotic and genetic cues for algal development.

48. Chlorophyta and Coral reefs

49. Coral Reefs Acropora - staghornPorites – finger coral Acropora - ElkhornMontastrea – boulder coral

50. Global Distn

51. Reef Zonation Lagoon Back-reef Reef flat Rim Spur-and- groove Slope Deep plain

52. GBR – Heron Island

53. Reef Plant-Animal interactions "The Living Coral Reef is one of the most diverse and complex communities in the world". The Florida Keys coral reef community presents approximately 107 species of corals (over 80% of all coral species of the tropical Atlantic) and over 500 species of tropical fish. The interaction and interdependence among all these organisms is so critical that many reef inhabitants cannot live outside the reef zone (e.g. Grunts). Sunlight, water, fish, invertebrates and plants play major roles in the sustaining and building of the reef: –Sunlight --> Photosynthesis. –Water --> Brings nutrients, O2, CO2. –Fish --> Excrements help build and cement reef. –Invertebrates and Plants --> Secrete calcium carbonate sediments that cement reef; food source; also graze the reef algae, creating space for corals to get established and grow. http://www.reefrelief.org/ecosystem.html

54. Reef formation Fringing reefs – Fla Keys Barrier Reefs – GBR, Belize Atoll reefs – Pac volcanic islands

55. Reefs in peril 1960’s 2000’s In <40 ys more than 50% of reefs have declined globally!!!!!

56. Importance of herbivores: fish, urchins, snails Lytechinus die-off Caribbean- wide in 1983 results in macroalgal blooms on reefs

57. Alternate Stable States Coral dominated Nutrient poor, lots grazers Coral dominated Nutrient elevated, lots grazers Algal dominated Nutrient poor, few grazers Algae dominated Nutrient rich, few grazers

58. Bottom-up Vs Top-down Coral dominance under low nutrient, high grazer abundance. Algal dominance under high nutrient and/or low grazing. Bottom-up = eutrophication. Algae out-grow corals and smother recruits. Top-down = overfishing of large fish predators AND herbivores. Trophic cascade, results in too few micrograzers to check algal growth. Seen this before in seagrasses – remember Heck and Valentine 2006paper?

59. Summary Chlorophyta – ancestors of vascular plants 10% marine, high tropical diversity Unicell -> Filamentous -> Siphonous Ulva, Enteromorpha cosmopolitan indicators of eutrophication Coral reef algae and “alternate stable states”: eutrophication vs trophic cascade