Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 6 Multicellular Primary Producers: seaweeds and plants

Non-plant photosynthetic organisms Photosynthetic bacteria, unicellular algae and seaweeds

Multicellular algae: the seaweeds Also called macrophytes, macroalgae, macrobenthic algae

Classification of seaweeds and marine plants

5Characters  all eukaryotes  all multicellular  lack highly specialized structures and reproductive mechanisms characteristics of land plants

Figure 6.01 General structure

7  Thallus( 葉狀體 )  Blades( 葉片 ); 2 characters (no vein, identical on both sides)  Pneumatocyst ( 氣泡 )  Stipe ( 莖片 )  Holdfast ( 固著器 ) -- lack of transport abilities -- lack of transport abilities

8 Three types of seaweed  Green algae  Brown algae  Red algae -- Differences depends on the proportion of different pigments -- Differences depends on the proportion of different pigments

9 Green algae

10 Green algae  Phylum Chlorophyta  Most restricted to freshwater and terrestrial environments  7000 species; 10% is marine; many are unicellular  Distributed mainly in the bays, estuaries and isolated tidal pools  land plants may evolved directly from green algae  chlorophyll pigment

Figure 6.02 bottom sea lettuce Ulva( 海萵苣 )

Dead man’s finger -- extend from tropical to temperate waters

Calcareous green algae

Figure 6.04 Brown algae

15 Brown algae  Phylum Heterokontophyta, Class Phacophyta  Fucoxanthin( 褐藻素 ) dominate over chlorophyll  primary producers on temperate and polar rocky coasts  Almost 1500 species are marines  Include the largest and most complex seaweeds

Figure 6.05 rockweeds or wrack

Figure 6.06 rockweeds or wrack

18 Floating algae; Sargasso Sea, Kelps: great abundance in temperate and sub-polar latitudes. -- form kelp beds or forest

kelp Kelp forest

20 Kelps Found in deeper water below the lowest tide level Can grow at least 50 cm per day in optimal condition, reaches 100 m Among the richest, most productive environment in marine realm

Figure 6.09 Red algae

22 Red algae  Phylum Rhodophyta  red pigments; phycobilins mask chlorophyll  The largest group of seaweeds, about 4000 species; most exclusively marine  Found in most shallow water marine environment  Filamentous red algae and flatter branches

23 Coralline red algae

24 Coralline red algae  Smooth or rough encrusting growth on rocks  Warm-water coralline red algae actively involve in formation and development of coral reefs.

Life history (reproduction) Asexual reproduction and sexual reproduction

26 Asexual reproduction vegetative reproduction vegetative reproduction -- (1) fragments of thallus, (2) -- (1) fragments of thallus, (2) produce spores produce spores zoospore ( 游動孢子 ) zoospore ( 游動孢子 )

Sexual reproduction create gametes and form zygotes

28 Four basic patterns (types) of reproduction

Figure 6.11a Type A: most common among all groups of seaweeds

Figure 6.11b Type B: unique to red algae -- 3 generations

Figure 6.11c Type C: some green and brown algaes -- similar to the sexual reproduction

Figure 6.11d Type D: in some green algaes

33 Gamete development can be influenced by : (1)amount of nutrients, (2) temperature, (3) length of day light Trigger factors : splashing of incoming tide, or by chemical messagers of opposite sex. -- Some male and female gametes timed to release at the same time

Figure 6.12 Economic importance Farming or mariculture of seaweeds

35 Economic importance -- Phycocollids -- Algin -- carrageenan -- Agar; -- Seaweeds

36 Economic importance Phycocollids: food processing; form suspension and gel Algin: stabilizer and emulsifier, baking, chemical industries, pharmaceutical, texture, etc. Carrageenan: emulsifier, diaery products Agar: foods, canning, cosmetics, medicine Seaweeds: fertilizer, hospitals, nutritional supplements, reduce soil acidity

37 Flowering plants about species, or angiosperms Divison Magnoliophyta -- Kingdom Plantae True roots, leaves, stem; specialized tissue for transport materials Reporduction by sporophyte (flower)

38 Seagrass  Truly marine plants  Characters; (1) rhizomes, (2) pollens are long and thread-like ; transported by water column of animal feces

Figure 6.13a Seagrass

Figure 6.13b Eelgrass -- about 60 species -- in many temperate and tropical regions -- inhabits shallow, well-protected coastal waters -- distinctively flat, ribbon-like leaves -- in oxygen-poor sediment

41 Salt marsh plants

42 Salt marsh plants  Cordgrass, land-plants tolerant of salt  Live in salt marshes and other temperate soft-bottom coastal areas  Submerged by seawater only at high tide  halophytes

43 Functions of Salt marsh  Highly productive, provide habitat and breeding grounds for many commercial species  Protection against erosion and provide natural water purification system

Figure 6.14 Mangrove

45 Mangrove  Shrubs and trees adapted to live along tropical and subtropical shores  Essentially land plants that can tolerate salt  About 80 mostly unrelated species of flowering plants

Adaptations prop roots

Viviparous seedWaxed leaves