I.Multicellular Algae - Seaweeds B.Green Algae (Chlorophyta) Mostly freshwater species (~700 marine species)Mostly freshwater species (~700 marine species) Some species common in nearshore environmentsSome species common in nearshore environments Structurally simpleStructurally simple Many unicellular or filamentousMany unicellular or filamentous Photosynthetic pigments and energy storage products similar to higher plantsPhotosynthetic pigments and energy storage products similar to higher plants May have shared a common ancestor with plantsMay have shared a common ancestor with plants No pigments to mask green colorNo pigments to mask green color HabitatHabitat Many live as epiphytesMany live as epiphytes Some species bore into calcium carbonate shellsSome species bore into calcium carbonate shells

I.Multicellular Algae - Seaweeds B.Green Algae (Chlorophyta) ExamplesExamples EnteromorphaEnteromorpha Often found in polluted areas; Used as bioassay toolOften found in polluted areas; Used as bioassay tool Ulva (Sea Lettuce)Ulva (Sea Lettuce) Found in areas with high nutrient levelsFound in areas with high nutrient levels Valonia (Bubble Algae)Valonia (Bubble Algae) Tropical and subtropicalTropical and subtropical CaulerpaCaulerpa Invasive species (C. taxifolia)Invasive species (C. taxifolia) Codium (Dead Man’s Fingers)Codium (Dead Man’s Fingers) MultinucleatedMultinucleated HalimedaHalimeda Calcareous algaCalcareous alga Ulva Valonia Caulerpa

Fig Ulva Codium Halimeda

I.Multicellular Algae - Seaweeds C.Brown Algae (Phaeophyta) Mostly marine (~1500 species)Mostly marine (~1500 species) Includes largest and most complex algae - kelpsIncludes largest and most complex algae - kelps Especially abundant on rocky coasts in temperate and polar regionsEspecially abundant on rocky coasts in temperate and polar regions Dominant accessory pigment is fucoxanthinDominant accessory pigment is fucoxanthin Imparts yellow-brown to brown colorImparts yellow-brown to brown color Structurally simple to complexStructurally simple to complex Some with simple flat thalli (Padina)Some with simple flat thalli (Padina) Others with complex structuresOthers with complex structures Holdfast, stipe, blade, pneumatocystsHoldfast, stipe, blade, pneumatocysts Includes fast growing speciesIncludes fast growing species Some kelps can grow up to 50 cm per day!Some kelps can grow up to 50 cm per day! Most anchored to substrateMost anchored to substrate Some float (Sargassum – Sargasso Sea)Some float (Sargassum – Sargasso Sea) Common in intertidal zoneCommon in intertidal zone Good at withstanding mechanical stressGood at withstanding mechanical stress Tolerant of exposure and desiccationTolerant of exposure and desiccation Padina Sargassum

I.Multicellular Algae - Seaweeds C.Brown Algae (Phaeophyta) ExamplesExamples Fucus (Rockweeds)Fucus (Rockweeds) Intertidal and subtidal species; Ecologically importantIntertidal and subtidal species; Ecologically important Laminaria (Kelp)Laminaria (Kelp) Some species consist of a single bladeSome species consist of a single blade Commonly used for foodCommonly used for food Postelsia (Sea Palm)Postelsia (Sea Palm) Usually on exposed rocky shorelinesUsually on exposed rocky shorelines Fig Fucus Laminaria

I.Multicellular Algae - Seaweeds C.Brown Algae (Phaeophyta) ExamplesExamples Fucus (Rockweeds)Fucus (Rockweeds) Intertidal and subtidal species; Ecologically importantIntertidal and subtidal species; Ecologically important Laminaria (Kelp)Laminaria (Kelp) Some species consist of a single bladeSome species consist of a single blade Commonly used for foodCommonly used for food Postelsia (Sea Palm)Postelsia (Sea Palm) Usually on exposed rocky shorelinesUsually on exposed rocky shorelines Egregia (Feather Boa)Egregia (Feather Boa) Common on rocky Pacific coastCommon on rocky Pacific coast Pelagophycus (Elk Kelp)Pelagophycus (Elk Kelp) Large floatLarge float Macrocystis (Giant Kelp)Macrocystis (Giant Kelp) May reach 100 m and grow up to 50 cm day -1May reach 100 m and grow up to 50 cm day -1 Most common in cold waterMost common in cold water Fucus Laminaria

Egregia Pelagophycus Macrocystis

I.Multicellular Algae - Seaweeds D.Red Algae (Rhodophyta) Mostly marine (~4000 species)Mostly marine (~4000 species) Common in shallow water but also found in very deep waterCommon in shallow water but also found in very deep water Contain accessory pigments called phycobilinsContain accessory pigments called phycobilins Structurally less complex than brown algaeStructurally less complex than brown algae Most are filamentousMost are filamentous Much smaller than large brown algaeMuch smaller than large brown algae May be heterotrophic or parasiticMay be heterotrophic or parasitic May incorporate calcium carbonate into tissues (Why?)May incorporate calcium carbonate into tissues (Why?) Coralline red algaeCoralline red algae May be important in formation and cementing of coral reefsMay be important in formation and cementing of coral reefs May contribute to formation of carbonate sandMay contribute to formation of carbonate sand Some encrusting, others arborescentSome encrusting, others arborescent Many are commercially importantMany are commercially important Sebdenia

Pelagophycus Halimeda Porphyra

I.Multicellular Algae - Seaweeds E.Life History 1.Asexual Fragmentation – Especially in species with no holdfastFragmentation – Especially in species with no holdfast Spores – Resistant dispersal stagesSpores – Resistant dispersal stages Zoospores – Flagella permit motilityZoospores – Flagella permit motility 2.Sexual Rare in unicellular algae; common in multicellular formsRare in unicellular algae; common in multicellular forms Gametes produced by meiosisGametes produced by meiosis Two types of life stagesTwo types of life stages Haploid (n) – gametophyte generationHaploid (n) – gametophyte generation Diploid (2n) – sporophyte generationDiploid (2n) – sporophyte generation Alternation of generations between gametophyte and sporophyte stagesAlternation of generations between gametophyte and sporophyte stages Four basic patterns of sexual reproductionFour basic patterns of sexual reproduction

Fig. 6.11

I.Multicellular Algae - Seaweeds F.Economic Importance 1.Food Source HarvestedHarvested MaricultureMariculture Red algae (Porphyra, Eucheuma)Red algae (Porphyra, Eucheuma) Brown algae (Laminaria)Brown algae (Laminaria) 2.Products a.Phycocolloids Algin (Extracted from kelp; harvested with boats)Algin (Extracted from kelp; harvested with boats) Stabilizer, emulsifier for ice cream, cheeseStabilizer, emulsifier for ice cream, cheese Stabilizer to keep frostings and baked goods moistStabilizer to keep frostings and baked goods moist Thickener, emulsifier for shampoo, shaving cream, plastics, rubber, paints, cosmetics, textilesThickener, emulsifier for shampoo, shaving cream, plastics, rubber, paints, cosmetics, textiles Carrageenan (Extracted from red algae)Carrageenan (Extracted from red algae) Emulsifier for dairy products, toothpaste, puddingsEmulsifier for dairy products, toothpaste, puddings Agar (Extracted from red algae)Agar (Extracted from red algae) Used to form jellies, thicken mixturesUsed to form jellies, thicken mixtures Preserves, pharmaceutical applicationsPreserves, pharmaceutical applications b.Other Fertilizers, additives in animal feedsFertilizers, additives in animal feeds

II.Flowering Plants (Angiosperms) Flowering plants have true leaves, stems and roots (unlike multicellular algae)Flowering plants have true leaves, stems and roots (unlike multicellular algae) Contain specialized tissues that transport water, minerals and nutrientsContain specialized tissues that transport water, minerals and nutrients Dominant sporophyteDominant sporophyte Few truly marine speciesFew truly marine species Seagrasses entirely submerged most of the time, but other marine angiosperms intolerant of prolonged immersionSeagrasses entirely submerged most of the time, but other marine angiosperms intolerant of prolonged immersion Marine angiosperms expend considerable energy coping with effects of salt waterMarine angiosperms expend considerable energy coping with effects of salt water A.Seagrasses (50-60 species) Not true grasses (related to lilies)Not true grasses (related to lilies) Roots, stems and shoots grow from horizontal rhizomeRoots, stems and shoots grow from horizontal rhizome Flowers typically small and inconspicuous (Why?)Flowers typically small and inconspicuous (Why?) Pollen carried by water currents; No need to attract pollinatorsPollen carried by water currents; No need to attract pollinators

II.Flowering Plants (Angiosperms) A.Seagrasses 1.Eelgrass (Zostera) – Temperate Atl, Pac; Tropical Pac Most widely distributed; in shallow, protected coastal watersMost widely distributed; in shallow, protected coastal waters Common in oxygen-poor sedimentsCommon in oxygen-poor sediments Highly productive; provides shelter for many animalsHighly productive; provides shelter for many animals 2.Surf grass (Phyllospadix) – Temperate Pac Lives on rocky shores; experience wave actionLives on rocky shores; experience wave action May be exposed at low tideMay be exposed at low tide 3.Turtle grass (Thalassia) – Tropical Lives on muddy and sandy bottoms in calm waters to 10 mLives on muddy and sandy bottoms in calm waters to 10 m Stabilize sediments on landward sides of Caribbean reefsStabilize sediments on landward sides of Caribbean reefs

Fig. 6.13

Eelgrass (Zostera marina)

II.Flowering Plants (Angiosperms) A.Seagrasses 1.Eelgrass (Zostera) – Temperate Atl, Pac; Tropical Pac Most widely distributed; in shallow, protected coastal watersMost widely distributed; in shallow, protected coastal waters Common in oxygen-poor sedimentsCommon in oxygen-poor sediments Highly productive; provides shelter for many animalsHighly productive; provides shelter for many animals 2.Surf grass (Phyllospadix) – Temperate Pac Lives on rocky shores; experience wave actionLives on rocky shores; experience wave action May be exposed at low tideMay be exposed at low tide 3.Turtle grass (Thalassia) – Tropical Lives on muddy and sandy bottoms in calm waters to 10 mLives on muddy and sandy bottoms in calm waters to 10 m Stabilize sediments on landward sides of Caribbean reefsStabilize sediments on landward sides of Caribbean reefs

Fig. 6.13

Surf Grass (Phyllospadix scouleri)

II.Flowering Plants (Angiosperms) A.Seagrasses 1.Eelgrass (Zostera) – Temperate Atl, Pac; Tropical Pac Most widely distributed; in shallow, protected coastal watersMost widely distributed; in shallow, protected coastal waters Common in oxygen-poor sedimentsCommon in oxygen-poor sediments Highly productive; provides shelter for many animalsHighly productive; provides shelter for many animals 2.Surf grass (Phyllospadix) – Temperate Pac Lives on rocky shores; experience wave actionLives on rocky shores; experience wave action May be exposed at low tideMay be exposed at low tide 3.Turtle grass (Thalassia) – Tropical Lives on muddy and sandy bottoms in calm waters to 10 mLives on muddy and sandy bottoms in calm waters to 10 m Stabilize sediments on landward sides of Caribbean reefsStabilize sediments on landward sides of Caribbean reefs

Fig. 6.13

Turtle Grass (Thalassia species)